JP4940491B2

JP4940491B2 - Secondary battery

Info

Publication number: JP4940491B2
Application number: JP2000253733A
Authority: JP
Inventors: 哲郎南野; 洋平服部; 史彦 ▲よし▼井
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2000-08-24
Filing date: 2000-08-24
Publication date: 2012-05-30
Anticipated expiration: 2020-08-24
Also published as: JP2002075434A

Description

【０００１】
【発明の属する技術分野】
本発明は、極板を巻回した極板群を用いた高出力型の二次電池の構造、特に極板群中央の巻芯部の構成に関するものである。
【０００２】
【従来の技術】
近年、電動工具や電気自動車用電池として高出力・長寿命型電池の需要が高まっている。中でも電気自動車用電池は１０年と言われる車の寿命と同等の電池寿命が求められている。
【０００３】
電池が寿命を迎えるモードの１つに電解液の涸渇による電池内部抵抗の上昇がある。その原因は、正極・負極の活物質や芯材が電解液と反応し、セパレータ中に含まれる電解液が減少していくためである。これに対して、例えばペースト式ニッケル正極を用いるニッケル水素蓄電池では、正極に活物質としての水酸化ニッケルの他、酸化亜鉛などを添加することにより、ニッケル層間に結晶水を取り込んだγ型オキシ水酸化ニッケルの生成を抑制し、長寿命化を図ることや、負極に酸化イットリウムを添加することにより、負極合金の酸化を抑制し、電解液涸渇を回避する技術などが提案されている。しかしながら、これらの提案の技術だけでは電池に車と同等の寿命を確保するのは困難である。
【０００４】
【発明が解決しようとする課題】
従来から生産されている円筒型二次電池は、ある径をもつ巻芯を用いて、セパレータを間に介在させて正極と負極を巻回して渦巻状極板群を作製し、その両端面に集電体を溶接させるか、または負極をケースと接触させ、正極の一部に溶接されたリードを封口板と溶接し、電解液を注液して封口して電池を密閉するというものであった。そして、正極板の巻き始め側には、巻回時のクラックによる負極との短絡防止のため、通常、セパレータを２枚重ねにして用いられていた。このようにセパレータを二重にして用いた場合、正極・負極の極間距離が他の部分に比べ大きくなりこの部分の極間抵抗が大きくなるため、大電流で充放電する場合には巻芯部のセパレータが二重になっている部分の利用率は低くなっているという問題があり、二次電池の長寿命化を図る上でこの問題点は好ましくないことであった。そこで本発明は上記従来例の問題点を解消して長寿命の二次電池を実現しようとするものである。
【０００５】
【課題を解決するための手段】
本発明は上記目的を達成するために極板群の中央に大きな空間を構成することとした。そしてこの空間に多くの電解液を保持できる構造にしたことが特徴である。先述したように、通常、巻芯部にはクラック防止のため、セパレータが２枚重ねで用いられており、この部分の大電流充放電での利用率は低いので、この部分を削除しても、電池の内部抵抗はほとんど変化しない。従って、電池容量ではなく、電池の出力と寿命の長さがより要求されている場合、巻芯部の大電流充放電で利用率の低い部分を削除して電解液溜とすることで、電池の長寿命化を達成することができる。このために本願発明は請求項１記載に係るように、極板群の中央に円筒型巻芯空間部を構成し、円筒型巻芯空間部の内径をｄとし、円筒型ケースの内径をＤとした時に、０．１６≦ｄ／Ｄ≦０．３２とし、円筒型巻芯空間部には、円筒型巻芯空間部の容積に対して０．１〜２０％の容積を占める電解液流出阻止体を設け、電解液流出阻止体は、電解液を含浸して保持することができる対電解液性繊維体とし、円筒型巻芯空間部には電解液を貯溜させたものである。
【０００６】
【発明の実施の形態】
極板群を挿入する円筒型ケースの内径をＤ、円筒型巻芯空間部の内径をｄとすると、ｄ／Ｄが０．１６未満であると、円筒型巻芯空間部内に保持できる電解液量が少なくなるため、電池の延命効果は小さい。また、ｄ／Ｄが０．３２を越えると円筒型ケース内に極板群として挿入することが可能な極板全体の長さが短くなり、従って電池容量が小さくなりすぎ内部抵抗も上昇してしまう。そこで、円筒型巻芯空間の内径ｄは０．１６≦ｄ／Ｄ≦０．３２を満たす範囲内にあることが望ましい。
【０００７】
また、円筒型巻芯空間に電解液を保持させるにあたって、流れが自由の、つまりフリーの電解液をそのままにしていたのでは電池の製造工程において電解液が飛散し、電池内に保持される電解液量がばらつき、ひいては電池寿命もばらつきを生じる恐れがある。そこで、円筒型巻芯空間に、その容積全体の０．０１〜２０％の真体積を有する電解液流出阻止体を挿入することで、製造工程中に電池に対して振動を与えても電解液が飛散しないようにした。この電解液流出阻止体の形態としては、円筒型巻芯空間を上部から対電解液の蓋をするような形態とか、空間内に電解液を含浸保持させる繊維状の不織布等を詰めた形態等が適当である。
【０００８】
具体的な実施の形態を図１を参照して以下に述べる。なお本実施の形態はニッケル水素蓄電池を例として述べる。
【０００９】
作製した電池は直径２２ｍｍ，高さ４２．５ｍｍ，公称容量２４００ｍＡｈである。厚さ０．５４ｍｍ，長さ２８０ｍｍの焼結式ニッケル正極板１と、厚さ０．２７ｍｍ，長さ３３０ｍｍのペースト式水素吸蔵合金負極板２とを用い、それぞれの極板の長端部の一方は１ｍｍの芯材の露出した部分３，４を設け、それぞれの芯材部が反対向きになるように極板を配設し、さらに互いの極板芯材部が対極板よりも２ｍｍ突出するようにして、セパレータ５を間に介在させ、直径６．５ｍｍの巻芯を用いて正極板１，負極板２及びセパレータ５を渦巻状に巻回させ、外径約２０ｍｍ，高さ約３７ｍｍの極板群６を構成した。この極板群６の正極側の芯材部端面に集電体７、負極側の芯材部端面に集電体８をそれぞれ溶接して取り付けた。この、集電体７，８を溶接した極板群６を金属製の円筒型ケース９に挿入し、集電体７の中央部の穴に溶接電極を挿入して導電板１０を溶接し、集電体８の中央部と金属製の円筒型ケース９の底部を溶接した。比重１．３０の水酸化カリウム水溶液を５．５ミリリットル注液した後、封口板１１と円筒型ケース９をかしめて密閉電池Ａを作製した。
【００１０】
１２は極板群６の中央に直径６．５ｍｍの巻芯によって構成された円筒型巻芯空間部である。
【００１１】
また、外径６．５ｍｍの巻芯の代わりに外径５ｍｍの巻芯を用いて、極板長さをそれぞれ密閉電池Ａに対して１０ｍｍ長くした以外は密閉電池Ａと同様にして作製し、極板群に二つの集電体を溶接して、注液量を５．０ミリリットルにした他は密閉電池Ａと同様にして密閉電池Ｂを作製した。
【００１２】
一方、外径６．５ｍｍの巻芯の代わりに外径３．０ｍｍの巻芯を用いて、極板長さをそれぞれ密閉電池Ａに対して２５ｍｍ長くし、正極板の巻芯側に長さ５０ｍｍのセパレータを通常のセパレータに重ねて使用した以外は密閉電池Ａと同様にして作製し、極板群に二つの集電体を溶接して、注液量を４．５ミリリットルにした他は密閉電池Ａと同様にして密閉電池Ｃを比較例電池として作製した。
【００１３】
（評価）
密閉電池Ａ，Ｂ及びＣを室温にて、１．２Ａの電流で２．５時間充電し、１．２Ａの電流で電池の端子電圧が１Ｖになるまで放電する方式で１０回充放電を繰り返して電池を活性化させた。次に放電状態の密閉電池Ａ及びＢを１．１Ａの電流で１時間充電した後、１時間放置して、６０Ａの放電を１０秒間行った。この６０Ａ放電前後の電池電圧の差を電流値で除することにより、電池の直流抵抗を求めた。表１に密閉電池Ａ，Ｂ及びＣの１０サイクル目での電池の放電容量と直流抵抗値を示す。
【００１４】
【表１】

【００１５】
極板の長さが短くなるに従い、放電容量は小さくなる傾向が見られるが、極板の単位長さあたりの容量を比較すると密閉電池Ｃ（８．９２ｍＡｈ／ｍｍ）＜密閉電池Ｂ（８．９７ｍＡｈ／ｍｍ）＜密閉電池Ａ（９．２３ｍＡｈ／ｍｍ）となった。これは単位容量あたりの電解液量が増えたことにより、活物質利用率が向上したためと考えられる。また、直流抵抗値は密閉電池Ａ，Ｂ，Ｃともほぼ同様の値を示した。
【００１６】
次にこれら三種の電池を４５℃雰囲気下、４．８Ａにて２４分間充電、６分間の休止の後、４．８Ａにて０．９Ｖまで放電、６分間休止する、という方式で充放電を繰り返し、１００サイクル毎に直流抵抗の変化を調べた。その結果を図２に示す。
【００１７】
図２から、本発明の参考例である密閉電池Ａ及びＢは比較例の密閉電池Ｃに対して、直流抵抗が上昇し始める充放電サイクル数が大幅に大きくなっていることがわかる。これは極板群の巻芯の直径が密閉電池Ｃよりも密閉電池Ａ，Ｂが共に大きく、極板群中央に構成される空間が大きく注入される電解液量が多いことにより、長期にわたって電解液が極板間に供給されることによるものである。
【００１８】
【発明の効果】
以上のように、本発明によれば、長期間にわたって内部抵抗の低い長寿命型の二次電池を提供することができるものである。
【図面の簡単な説明】
【図１】密閉型電池の構成を示す半截側断面図
【図２】直流抵抗と充放電サイクル数との関係を示した図
【符号の説明】
１焼結式ニッケルの正極板
２ペースト式水素吸蔵合金の負極板
３，４芯材の露出した部分
５セパレータ
６極板群
７，８集電体
９金属製の円筒型ケース
１０導電板
１１封口板
１２極板群中央に構成された円筒型巻芯空間部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to the structure of a high-power secondary battery using an electrode plate group around which an electrode plate is wound, and more particularly to the configuration of a core portion at the center of the electrode plate group.
[0002]
[Prior art]
In recent years, there is an increasing demand for high-power and long-life batteries as power tools and batteries for electric vehicles. In particular, batteries for electric vehicles are required to have a battery life equivalent to that of a car that is said to be 10 years.
[0003]
One mode in which the battery reaches the end of its life is an increase in battery internal resistance due to electrolyte depletion. This is because the positive electrode / negative electrode active material and the core material react with the electrolytic solution, and the electrolytic solution contained in the separator decreases. On the other hand, for example, in a nickel metal hydride storage battery using a paste type nickel positive electrode, γ-type oxywater in which crystal water is taken in between nickel layers by adding zinc oxide or the like to the positive electrode in addition to nickel hydroxide as an active material. Techniques have been proposed in which the production of nickel oxide is suppressed to prolong the life, and the addition of yttrium oxide to the negative electrode suppresses oxidation of the negative electrode alloy and avoids electrolyte depletion. However, it is difficult to ensure a battery with a life equivalent to that of a car only with these proposed technologies.
[0004]
[Problems to be solved by the invention]
Conventionally produced cylindrical secondary batteries use a winding core having a certain diameter, wind a positive electrode and a negative electrode with a separator interposed therebetween, and form a spiral electrode plate group on both end faces. The current collector is welded, or the negative electrode is brought into contact with the case, the lead welded to a part of the positive electrode is welded to the sealing plate, the electrolyte is injected and sealed, and the battery is sealed. It was. In order to prevent a short circuit with the negative electrode due to cracks at the time of winding, two separators are usually used on the winding start side of the positive electrode plate. When double separators are used in this way, the distance between the positive and negative electrodes is greater than that of other parts, and the resistance between these parts is increased. There is a problem that the utilization factor of the part where the separators of the part are doubled is low, and this problem is not preferable for extending the life of the secondary battery. Therefore, the present invention is intended to solve the problems of the conventional example and realize a secondary battery having a long life.
[0005]
[Means for Solving the Problems]
In the present invention, in order to achieve the above object, a large space is formed in the center of the electrode plate group. And it is the characteristic that it was made the structure which can hold | maintain many electrolyte solutions in this space. As described above, normally, two separators are used to prevent cracks in the core part, and since the utilization factor in large current charge / discharge of this part is low, even if this part is deleted The internal resistance of the battery hardly changes. Therefore, if the battery output and the length of the life are more demanded than the battery capacity, the battery portion can be used as an electrolyte reservoir by removing the portion with low utilization due to large current charging / discharging of the core. Longer service life can be achieved. Therefore, according to the present invention , a cylindrical core space portion is formed in the center of the electrode plate group, the inner diameter of the cylindrical core space portion is d, and the inner diameter of the cylindrical case is D. In this case, 0.16 ≦ d / D ≦ 0.32, and the cylindrical core space portion occupies 0.1 to 20% of the volume of the cylindrical core space portion. A blocking body is provided, and the electrolytic solution outflow blocking body is an anti-electrolyte fibrous body that can be impregnated and held by the electrolytic solution, and the electrolytic solution is stored in the cylindrical core space .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Electrolyte that can be held in the cylindrical core space when d / D is less than 0.16, where D is the inner diameter of the cylindrical case into which the electrode plate group is inserted and d is the inner diameter of the cylindrical core space Since the amount is reduced, the life extension effect of the battery is small. Also, if d / D exceeds 0.32, the length of the entire electrode plate that can be inserted into the cylindrical case as a group of electrode plates is shortened, so that the battery capacity becomes too small and the internal resistance increases. End up. Therefore, it is desirable that the inner diameter d of the cylindrical core space is in a range satisfying 0.16 ≦ d / D ≦ 0.32.
[0007]
In addition, when the electrolytic solution is held in the cylindrical core space, if the flow is free, that is, the free electrolytic solution is left as it is, the electrolytic solution is scattered in the battery manufacturing process, and the electrolytic solution held in the battery is retained. There is a possibility that the amount of liquid varies, and the battery life also varies. Therefore, even if vibration is applied to the battery during the manufacturing process by inserting an electrolytic solution outflow prevention body having a true volume of 0.01 to 20% of the entire volume into the cylindrical core space, the electrolytic solution Was not scattered. As a form of this electrolyte outflow prevention body, a form in which a cylindrical core space is covered with an electrolyte solution from the top, a form in which a fibrous nonwoven fabric or the like that impregnates and holds the electrolyte solution is filled in the space, etc. Is appropriate.
[0008]
The concrete embodiments will be described below with reference to FIG. In the present embodiment, a nickel metal hydride storage battery will be described as an example.
[0009]
The produced battery has a diameter of 22 mm, a height of 42.5 mm, and a nominal capacity of 2400 mAh. A sintered nickel positive electrode plate 1 having a thickness of 0.54 mm and a length of 280 mm and a paste-type hydrogen storage alloy negative electrode plate 2 having a thickness of 0.27 mm and a length of 330 mm were used. One is provided with exposed

portions

3 and 4 of a 1 mm core material, and electrode plates are arranged so that the core material portions face in opposite directions, and each electrode plate core material portion protrudes 2 mm from the counter electrode plate. In this way, the separator 5 is interposed, and the positive electrode plate 1, the negative electrode plate 2 and the separator 5 are spirally wound using a winding core having a diameter of 6.5 mm, and the outer diameter is about 20 mm and the height is about 37 mm. The electrode plate group 6 was constructed. A current collector 7 was attached to the end surface of the core member on the positive electrode side of the electrode plate group 6 and a current collector 8 was attached to the end surface of the core member portion on the negative electrode side by welding. The electrode plate group 6 to which the current collectors 7 and 8 are welded is inserted into a cylindrical case 9 made of metal, a welding electrode is inserted into a hole in the center of the current collector 7, and the conductive plate 10 is welded. The center part of the current collector 8 and the bottom part of the metal cylindrical case 9 were welded. After injecting 5.5 ml of an aqueous potassium hydroxide solution having a specific gravity of 1.30, the sealing plate 11 and the cylindrical case 9 were caulked to produce a sealed battery A.
[0010]
Reference numeral 12 denotes a cylindrical core space formed by a core having a diameter of 6.5 mm in the center of the electrode plate group 6.
[0011]
Also, using a core with an outer diameter of 5 mm instead of a core with an outer diameter of 6.5 mm, the electrode plate length was made 10 mm longer than that of the sealed battery A, respectively. A sealed battery B was produced in the same manner as the sealed battery A, except that two current collectors were welded to the electrode plate group, and the injection volume was 5.0 ml.
[0012]
On the other hand, instead of using a core with an outer diameter of 6.5 mm, a core with an outer diameter of 3.0 mm is used, and the length of the electrode plate is increased by 25 mm with respect to the sealed battery A. Except that a 50 mm separator was used on top of a normal separator, it was prepared in the same manner as the sealed battery A, and two current collectors were welded to the electrode plate group to make the injection volume 4.5 ml. A sealed battery C was prepared as a comparative battery in the same manner as the sealed battery A.
[0013]
(Evaluation)
Charging sealed batteries A, B and C at room temperature with a current of 1.2 A for 2.5 hours, and charging and discharging 10 times with a method of discharging until the terminal voltage of the battery reaches 1 V with a current of 1.2 A The battery was activated. Next, the sealed batteries A and B in a discharged state were charged with a current of 1.1 A for 1 hour, then left for 1 hour, and discharged at 60 A for 10 seconds. The direct current resistance of the battery was determined by dividing the difference in battery voltage before and after the 60A discharge by the current value. Table 1 shows the discharge capacity and DC resistance value of the sealed batteries A, B and C at the 10th cycle.
[0014]
[Table 1]

[0015]
Although the discharge capacity tends to decrease as the length of the electrode plate becomes shorter, when comparing the capacity per unit length of the electrode plate, the sealed battery C (8.92 mAh / mm) <the sealed battery B (8. 97 mAh / mm) <sealed battery A (9.23 mAh / mm). This is presumably because the utilization rate of the active material was improved by increasing the amount of electrolyte per unit capacity. Further, the DC resistance values were almost the same for the sealed batteries A, B and C.
[0016]
Next, these three types of batteries are charged and discharged in a 45 ° C. atmosphere by charging at 4.8 A for 24 minutes, resting for 6 minutes, discharging to 0.9 V at 4.8 A, and resting for 6 minutes. Repeatedly, the change in DC resistance was examined every 100 cycles. The result is shown in FIG.
[0017]
From FIG. 2, it can be seen that the sealed batteries A and B, which are reference examples of the present invention , have a significantly increased number of charge / discharge cycles in which the DC resistance starts to increase compared to the sealed battery C of the comparative example . This is the electrode plate group of the core diameter dense 閉電 pond C than denser 閉電 pond A, B are both large, that amount of electrolyte solution space formed in the electrode assembly center is injected larger often This is because the electrolyte is supplied between the electrode plates over a long period of time.
[0018]
【Effect of the invention】
As described above, according to the present invention, it is possible to provide a long-life secondary battery having a low internal resistance over a long period of time.
[Brief description of the drawings]
FIG. 1 is a cross-sectional side view showing a configuration of a sealed battery. FIG. 2 is a diagram showing the relationship between DC resistance and the number of charge / discharge cycles.
DESCRIPTION OF SYMBOLS 1 Positive electrode plate of sintered nickel 2 Negative electrode plate 3 of paste type

hydrogen storage alloy

3, 4 Exposed part of core material 5 Separator 6 Electrode plate group 7, 8 Current collector 9 Metal cylindrical case 10 Conductive plate 11 Sealing Plate 12 Cylindrical core space configured at the center of the electrode plate group

Claims

正極板と負極板とをセパレータを介して巻回して構成した極板群と、前記極板群を収納する円筒型ケースと、前記円筒型ケースを封口する封口板と、前記封口板と正極板あるいは負極板のうちのいずれか一方の電極板とを電気的に接続する接続端子を備えた二次電池において、前記極板群の中央に円筒型巻芯空間部を構成し、前記円筒型巻芯空間部の内径をｄとし、前記円筒型ケースの内径をＤとした時に、０．１６≦ｄ／Ｄ≦０．３２とし、前記円筒型巻芯空間部には、前記円筒型巻芯空間部の容積に対して０．１〜２０％の容積を占める電解液流出阻止体を設け、前記電解液流出阻止体は、電解液を含浸して保持することができる対電解液性繊維体とし、前記円筒型巻芯空間部には電解液を貯溜させたことを特徴とする二次電池。An electrode plate group configured by winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween, a cylindrical case for housing the electrode plate group, a sealing plate for sealing the cylindrical case, the sealing plate and the positive electrode plate Alternatively, in a secondary battery including a connection terminal for electrically connecting any one of the negative electrode plates, a cylindrical core space portion is formed at the center of the electrode plate group, and the cylindrical winding When the inner diameter of the core space portion is d and the inner diameter of the cylindrical case is D, 0.16 ≦ d / D ≦ 0.32, and the cylindrical core space portion includes the cylindrical core space. An electrolytic solution outflow prevention body occupying a volume of 0.1 to 20% with respect to the volume of the part is provided, and the electrolytic solution outflow prevention body is an anti-electrolytic solution fibrous body that can be impregnated with and retained by the electrolytic solution. A secondary battery in which an electrolytic solution is stored in the cylindrical core space.

前記対電解液性繊維体は不織布であることを特徴とする請求項１記載の二次電池。 The secondary battery according to claim 1, wherein the anti-electrolyte fibrous body is a nonwoven fabric .

正極板と負極板とをセパレータを介して巻回して構成した極板群と、前記極板群を収納する円筒型ケースと、前記円筒型ケースを封口する封口板と、前記封口板と正極板あるいは負極板のうちのいずれか一方の電極板とを電気的に接続する接続端子を備えた二次電池において、前記極板群の中央に円筒型巻芯空間部を構成し、前記円筒型巻芯空間部の内径をｄとし、前記円筒型ケースの内径をＤとした時に、０．１６≦ｄ／Ｄ≦０．３２とし、前記円筒型巻芯空間部には、前記円筒型巻芯空間部の容積に対して０．１〜２０％の容積を占める電解液流出阻止体を設け、前記電解液流出阻止体は、対電解液性蓋体とし、前記円筒型巻芯空間部には電解液を貯溜させたことを特徴とする二次電池。 An electrode plate group configured by winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween, a cylindrical case for housing the electrode plate group, a sealing plate for sealing the cylindrical case, the sealing plate and the positive electrode plate Alternatively, in a secondary battery including a connection terminal for electrically connecting any one of the negative electrode plates, a cylindrical core space portion is formed at the center of the electrode plate group, and the cylindrical winding When the inner diameter of the core space portion is d and the inner diameter of the cylindrical case is D, 0.16 ≦ d / D ≦ 0.32, and the cylindrical core space portion includes the cylindrical core space. An electrolytic solution outflow prevention body occupying a volume of 0.1 to 20% with respect to the volume of the part is provided, the electrolytic solution outflow prevention body is an anti-electrolytic solution lid, and the cylindrical core space portion is electrolyzed. A secondary battery characterized by storing liquid .

正極板と負極板とをセパレータを介して巻回して構成した極板群と、前記極板群を収納する円筒型ケースと、前記円筒型ケースを封口する封口板と、前記封口板と正極板あるいは負極板のうちのいずれか一方の電極板とを電気的に接続する接続端子を備えた二次電池において、前記極板群の中央に円筒型巻芯空間部を構成し、前記円筒型巻芯空間部の内径をｄとし、前記円筒型ケースの内径をＤとした時に、０．１６≦ｄ／Ｄ≦０．３２とし、前記円筒型巻芯空間部には、前記円筒型巻芯空間部の容積に対して０．１〜２０％の容積を占める電解液流出阻止体を設け、前記電解液流出阻止体は、対電解液性繊維体と対電解液性蓋体とからなり、前記円筒型巻芯空間部には電解液を貯溜させたことを特徴とする二次電池。 An electrode plate group configured by winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween, a cylindrical case for housing the electrode plate group, a sealing plate for sealing the cylindrical case, the sealing plate and the positive electrode plate Alternatively, in a secondary battery including a connection terminal for electrically connecting any one of the negative electrode plates, a cylindrical core space portion is formed at the center of the electrode plate group, and the cylindrical winding When the inner diameter of the core space portion is d and the inner diameter of the cylindrical case is D, 0.16 ≦ d / D ≦ 0.32, and the cylindrical core space portion includes the cylindrical core space. An electrolytic solution outflow prevention body occupying a volume of 0.1 to 20% with respect to the volume of the part is provided, and the electrolytic solution outflow prevention body is composed of an antielectrolytic fiber body and an antielectrolytic solution lid, A secondary battery in which an electrolytic solution is stored in a cylindrical core space .