【０００１】
【発明の属する技術分野】
円筒型蓄電池に関するものである。
【０００２】
【従来の技術】
正・負極板をセパレータを介して巻回した極板群（エレメント）を備えた円筒型蓄電池は、その構造上、蓄電池内で発生した熱は電槽側面に面している部分では放熱され易いが、蓄電池の中心部では放熱され難い特性を有している。そのため蓄電池内の中心部と外周部とに温度差が生じ、蓄電池の中心部の高温により劣化が促進され短寿命になる問題を抱えている。
【０００３】
また、円筒型蓄電池は角型蓄電池のように複数の単電池（以降、セルという）を一体化した、いわゆる、モノブロックタイプの蓄電池はその構造上、製造し難く、通常、セルの状態で製造され使用時に必要な電圧になるよう複数個接続される。このような蓄電池群を組電池と称している。組電池において、各セルを密接して設置した場合、内部に位置するセル程放熱が悪くなり、セル間での温度差が発生する。温度差が発生すると、特に充電時の充電受入特性に差が生じて充電状態のアンバランスが発生する。温度の高いセルは過充電を受け、寿命劣化が促進され特定のセルにより寿命が制限される問題も抱えている。その対策として組電池を形成する場合には各セル間の温度差を低減するためセル間に隙間を設け、蓄電池側面からの放熱をし易くしている。さらに、冷却用の風を送って冷却効果を高めたりしている。このことによって蓄電池間の温度差は低減されるがセル内での中心部と外周部との温度差は依然、解消されない。さらに、このような方式では組電池内に無駄な空間を設けなければならず、組電池の容積効率、すなわちエネルギー密度（Ｗｈ／ｌ）が低くなる欠点をも有している。
【０００４】
【発明が解決しようとする課題】
発明が解決しようとする課題は、円筒型蓄電池の単電池（セル）内で発生する中心部と外周部との温度差ならびにこれらセルで構成される組電池でのセル間の温度差を低減し、安定した寿命性能を有するセルあるいは組電池を提供するものである。
【０００５】
【発明が解決するための手段】
上記問題を解決する手段として、請求項１によれば、正・負極板をセパレータを介して巻回した極板群を備えた円筒型蓄電池において、該蓄電池は極板群の巻回軸方向の貫通孔を有し、該蓄電池の外径をＲ、該貫通孔の直径をｒとした時、０．０５Ｒ≦ｒ≦０．２Ｒを特徴とするものである。
【０００６】
円筒型蓄電池の中心部に極板群の巻回軸方向に貫通孔を設けると、貫通孔内の空気の冷却作用により該蓄電池中心部の熱が放散され易く、従来のような蓄電池内での温度差が低減され、安定した寿命性能が得られる。また、このセルを複数個用いて組電池を構成した場合、各セルが貫通孔による冷却効果を有しているので従来のように各セル間に隙間を設ける必要がなく、密接して設置しても、内部に位置するセルと端のセルとの温度差が大幅に低減される。したがって、寿命性能の安定した組電池が得られる。
【０００７】
円筒型蓄電池に設ける貫通孔の直径は大きい方が冷却効果を増すのは当然であるが、貫通孔によって円筒型蓄電池の内容積が減少し、貫通孔容積を含んだ円筒型蓄電池全体の容積から該蓄電池の容積効率、すなわちエネルギー密度（Ｗｈ／ｌ）を評価した場合、該貫通孔が大きくなるほどエネルギー密度が低下するマイナス面がある。発明者は、円筒型蓄電池の外径Ｒに対して貫通孔の直径ｒが種々異なる電槽を作製し、貫通孔直径ｒの冷却効果および円筒型蓄電池のエネルギー密度に及ぼす影響について試験を行い、貫通孔直径／蓄電池外径が一定の範囲内であれば冷却効果を有し、容量の低下も問題ない程度に留められることを見出した。本発明はその知見に基づくもので、貫通孔によるエネルギー密度、すなわち容量低下が貫通孔を有しない従来の円筒型鉛蓄電池の容量と比べて問題ない範囲内で、貫通孔の冷却効果を効率よく得るためには、蓄電池外径をＲ、該貫通孔直径をｒとした時、０．０５Ｒ≦ｒ≦０．２Ｒの関係を維持することが好ましいことがわかった。
【０００８】
【発明の実施の形態】
【実施例】
本発明を実施例に基づいて詳細に説明する。
【０００９】
図１は、本発明の実施例を示す要部透視斜視図で、１は円筒型蓄電池、２は正極端子、３は負極端子、４は安全弁、５は円筒型蓄電池の中心部に極板群の巻回軸方向に設けた貫通孔で、蓄電池外径に対して約０．１の比率の直径を有している。
【００１０】
円筒型蓄電池の中心部に極板群の巻回軸方向に貫通孔を設けた場合、蓄電池外径をＲ、該貫通孔の直径をｒとした時、０．０５Ｒ≦ｒ≦０．２Ｒ有していることが効果的であることを明らかにするために以下の試験を行った。
〔試験１〕
まず、定格容量１０Ａｈ（０．２Ｃ）（Ｃ：定格容量）の円筒型鉛蓄電池用電槽で各種直径の異なる貫通孔を有する電槽を作製した。これらの電槽に正・負極板をセパレータを介して巻回した極板群（エレメント）を挿入し、円筒型鉛蓄電池を作製した。まず、試験はセルのみで行い、貫通孔の蓄電池容量に及ぼす影響を調べるために０．２ＣＡ（Ｃ：定格容量、Ａ：電流の単位）の容量試験を行った。次に、１ＣＡ（Ｃ：蓄電池の定格容量、Ａ：電流の単位）の電流による過充電試験を行い、蓄電池内の温度を温度センサーで測定して貫通孔の放熱効果を評価した。試験はいずれも２５℃の雰囲気中で行った。試験蓄電池内容および試験結果を表１に示す。容量は、従来品の貫通孔を有していない定格容量１０Ａｈ（０．２Ｃ）の円筒型鉛蓄電池の容量を１００とした時の比率で表した
【００１１】
【表１】
【００１２】
表１が示すように、貫通孔直径／蓄電池外径が０．０３と小さいＮｏ．２の蓄電池は貫通孔のないＮｏ１の容量と変わらなかったが、０．０３では貫通孔の直径が小さすぎて冷却効果があまり得られなかった。本発明の範囲内である貫通孔直径／蓄電池外径が０．０５であるＮｏ．３の容量は従来品と変わらず、貫通孔の冷却効果も認められた。このように、円筒型蓄電池内に蓄電池外径に対して０．０３〜０．０５の直径を有する貫通孔を設けても貫通孔を有しない蓄電池の容量と変わらなかった。その理由は、円筒型蓄電池では長尺極板を巻回するのであるが、巻き始めの中心部分には貫通孔が生成され、その部分は充・放電に関与しないので、本発明の貫通孔に沿って巻き始める方式でも、貫通孔の直径比率が０．０３〜０．０５程度であれば貫通孔のない蓄電池の中心部の形状とあまり変わらない状態であり、容量に影響を与えなかったと考えられる。貫通孔直径／蓄電池外径が０．１のＮｏ．４では容量が約４％減になるが、貫通孔の冷却効果がより大きくなってきている。貫通孔直径／蓄電池外径が０．２のＮｏ．５では容量が６％減になっており、容量低下の許容できる限界といえる。貫通孔直径／蓄電池外径が本発明の範囲外の０．３であるＮｏ．６では、冷却効果は非常によかったが、容量が１１％減になっておりその点で問題である。
【００１３】
以上の試験結果から、貫通孔を設ける場合、その直径ｒを蓄電池外径Ｒに対して０．０５Ｒ≦ｒ≦０．２Ｒにすれば、貫通孔による容量低下が許容できる範囲内に収まり、大きな冷却効果が得られることがわかった。特に、冷却効果を重視した場合、容量減が約４％と貫通孔を有しない円筒型鉛蓄電池との差が小さく、冷却効果が顕著に得られる貫通孔直径／蓄電池外径＝０．１が好ましいといえる
【００１４】
。
次に、貫通孔を設けた円筒型蓄電池を組電池で使用した場合の放熱効果について試験した結果を以下に示す。
〔試験２〕
試験１と同じ定格容量１０Ａｈの円筒型鉛蓄電池で、貫通孔直径／蓄電池外径、０．１および０．２を有する貫通孔を設けた蓄電池を作製し、１列、５個を２列、合計１０個をセル間に隙間を設けず密接して並べた組電池を形成し、試験１と同じ、１ＣＡの過充電試験を行い、セル間の温度差を温度センサーを用いて測定した。試験は、２５℃の雰囲気中で行った。その試験内容および結果を表２
に示す。
【００１５】
【表２】
【００１６】
表２に示すように、従来品の貫通孔を設けない円筒型鉛蓄電池Ａは、密接してセルを並べた場合、中央のセルの放熱が悪いために温度が上昇し、端のセルとの温度差が８℃にもなった。一方、本発明の貫通孔直径／蓄電池外径が０．１の貫通孔を設けた蓄電池Ｂでは、セル間の温度差が４℃まで低下でき、貫通孔直径／蓄電池外径が０．２の貫通孔を設けたＣでは、その温度差が２℃までに抑えることができ、本発明の蓄電池内に貫通孔を設けることが組電池での蓄電池間の温度差を低減するのに有効であることが明らかになった。
【００１７】
また、環境温度が高いところで使用する場合に、組電池に対して送風による冷却を行うことがあるが、その場合も、蓄電池に貫通孔を設けると、風が該貫通孔内を通過する構造なので貫通孔のない蓄電池に比べると数段冷却効果が優れていることがわかった。
【００１８】
【発明の効果】
以上説明したように、円筒型蓄電池は、その構造上、蓄電池内で発生した熱は電槽側面に面している部分での放熱はされ易いが蓄電池の中心部では放熱され難い特性を有している。そのため蓄電池内で温度差が生じ、蓄電池の中央部の高温により劣化が促進され短寿命になる問題を抱えている。また、該単電池（セル）を複数個接続した組電池では、中央のセルと端のセルでは放熱特性が異なるため、セル間に温度差が生じ、温度の高いセルにより蓄電池寿命が制限される問題をも抱えていた。これに対して、円筒型蓄電池の中心部に極板群の巻回軸方向の貫通孔を設け、該蓄電池の外径をＲ、該貫通孔の直径をｒとした時、０．０５Ｒ≦ｒ≦０．２Ｒの関係を維持することによって蓄電池中心部が効果的に冷却され、単セル内での温度差および組電池でのセル間の温度差が低減され、貫通孔の存在による容量低下を最小限に抑えることができ、安定した寿命性能が得られ、その工業的効果が大である。
【図面の簡単な説明】
【図１】本発明の実施例を示す要部透視斜視図。
【符号の説明】
１ 円筒型鉛蓄電池
２ 正極端子
３ 負極端子
４ 安全弁
５ 貫通孔[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cylindrical storage battery.
[0002]
[Prior art]
A cylindrical storage battery provided with an electrode group (element) in which a positive / negative plate is wound with a separator interposed therebetween has a structure in which heat generated in the storage battery is easily radiated at a portion facing the side of the battery case. However, it has a characteristic that heat is hardly dissipated in the central part of the storage battery. For this reason, a temperature difference occurs between the central portion and the outer peripheral portion of the storage battery, and there is a problem that the high temperature of the central portion of the storage battery promotes deterioration and shortens the life.
[0003]
Also, a cylindrical storage battery is a monoblock storage battery in which a plurality of unit cells (hereinafter, referred to as cells) are integrated like a prismatic storage battery. And a plurality of them are connected so as to have a necessary voltage at the time of use. Such a storage battery group is called an assembled battery. In the assembled battery, when the cells are closely arranged, the heat radiation becomes worse as the cells are located inside, and a temperature difference occurs between the cells. When a temperature difference occurs, a difference occurs in charge receiving characteristics particularly during charging, and an imbalance occurs in the state of charge. A cell having a high temperature is overcharged, and has a problem that its life is accelerated and its life is limited by a specific cell. As a countermeasure, when a battery pack is formed, a gap is provided between the cells to reduce the temperature difference between the cells, thereby facilitating heat radiation from the side surface of the storage battery. Further, cooling air is sent to enhance the cooling effect. As a result, the temperature difference between the storage batteries is reduced, but the temperature difference between the central portion and the outer peripheral portion in the cell is still not eliminated. Further, such a system requires useless space in the battery pack, and has a disadvantage that the volumetric efficiency of the battery pack, that is, the energy density (Wh / l) is lowered.
[0004]
[Problems to be solved by the invention]
The problem to be solved by the present invention is to reduce the temperature difference between the central part and the outer peripheral part, which occurs in a single cell (cell) of a cylindrical storage battery, and the temperature difference between cells in a battery pack composed of these cells. Another object of the present invention is to provide a cell or a battery pack having stable life performance.
[0005]
Means for Solving the Invention
As means for solving the above problem, according to claim 1, in a cylindrical storage battery provided with an electrode plate group in which positive and negative electrode plates are wound via a separator, the storage battery is arranged in the winding axis direction of the electrode plate group. It has a through-hole, and when the outer diameter of the storage battery is R and the diameter of the through-hole is r, 0.05R ≦ r ≦ 0.2R.
[0006]
If a through hole is provided in the center of the cylindrical storage battery in the direction of the winding axis of the electrode plate group, the heat in the center of the storage battery is easily dissipated by the cooling action of the air in the through hole. The temperature difference is reduced, and stable life performance is obtained. Further, when a battery pack is constructed by using a plurality of these cells, since each cell has a cooling effect by the through hole, there is no need to provide a gap between the cells as in the conventional case, and the cells are closely mounted. Even so, the temperature difference between the cell located inside and the cell at the end is greatly reduced. Therefore, an assembled battery having stable life performance can be obtained.
[0007]
It is natural that the larger the diameter of the through-hole provided in the cylindrical storage battery increases the cooling effect, but the inner volume of the cylindrical storage battery is reduced by the through-hole, and from the volume of the entire cylindrical storage battery including the through-hole volume. When the volume efficiency of the storage battery, that is, the energy density (Wh / l) is evaluated, there is a downside that the energy density decreases as the through hole increases. The inventor made a battery case in which the diameter r of the through-hole was different from the outer diameter R of the cylindrical storage battery, and performed tests on the cooling effect of the through-hole diameter r and the effect on the energy density of the cylindrical storage battery. It has been found that when the ratio of the diameter of the through-holes / the outer diameter of the storage battery is within a certain range, a cooling effect is obtained, and the capacity can be reduced to a level that does not cause any problem. The present invention is based on the findings, and efficiently reduces the cooling effect of the through-hole, within a range in which the energy density due to the through-hole, that is, the capacity reduction is not a problem compared to the capacity of the conventional cylindrical lead-acid battery having no through-hole. In order to obtain, it is found that it is preferable to maintain the relationship of 0.05R ≦ r ≦ 0.2R, where R is the outer diameter of the storage battery and r is the diameter of the through hole.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
【Example】
The present invention will be described in detail based on examples.
[0009]
FIG. 1 is a perspective view of a main part showing an embodiment of the present invention, wherein 1 is a cylindrical storage battery, 2 is a positive terminal, 3 is a negative terminal, 4 is a safety valve, and 5 is an electrode plate group at the center of the cylindrical storage battery. And has a diameter of about 0.1 with respect to the outer diameter of the storage battery.
[0010]
When a through hole is provided in the center part of the cylindrical storage battery in the direction of the winding axis of the electrode group, when the outer diameter of the storage battery is R and the diameter of the through hole is r, 0.05R ≦ r ≦ 0.2R is present. The following test was conducted to clarify that the above is effective.
[Test 1]
First, a battery case having through-holes having various diameters was prepared as a cylindrical lead-acid battery case having a rated capacity of 10 Ah (0.2 C) (C: rated capacity). An electrode group (element) in which positive and negative electrode plates were wound with a separator interposed therebetween was inserted into these battery containers to produce a cylindrical lead-acid battery. First, the test was performed only on the cells, and a capacity test of 0.2 CA (C: rated capacity, A: current unit) was performed to examine the effect of the through-hole on the storage battery capacity. Next, an overcharge test was performed with a current of 1 CA (C: rated capacity of the storage battery, A: current unit), and the temperature inside the storage battery was measured by a temperature sensor to evaluate the heat dissipation effect of the through-hole. All tests were performed in an atmosphere at 25 ° C. Table 1 shows the test battery contents and the test results. The capacity is represented by a ratio when the capacity of a conventional lead-acid battery having a rated capacity of 10 Ah (0.2 C) having no through hole and a capacity of 100 is defined as 100.
[Table 1]
As shown in Table 1, the through hole diameter / storage battery outer diameter was as small as 0.03. The storage battery of No. 2 was the same as the capacity of No. 1 having no through-hole, but with 0.03, the diameter of the through-hole was too small to obtain a sufficient cooling effect. In the case of No. 5 in which the ratio of the diameter of the through hole to the outer diameter of the storage battery is 0.05 within the scope of the present invention. The capacity of No. 3 was not different from that of the conventional product, and the cooling effect of the through hole was also recognized. Thus, even if a through hole having a diameter of 0.03 to 0.05 with respect to the outer diameter of the storage battery was provided in the cylindrical storage battery, the capacity was the same as that of the storage battery having no through hole. The reason is that in a cylindrical storage battery, a long electrode plate is wound.However, a through hole is formed at the center of the beginning of winding, and that portion is not involved in charging / discharging. Even in the method of starting winding along, if the diameter ratio of the through hole is about 0.03 to 0.05, the shape is not so different from the shape of the central part of the storage battery without the through hole, and it is considered that the capacity was not affected. Can be No. with a through-hole diameter / storage battery outer diameter of 0.1. In No. 4, although the capacity is reduced by about 4%, the cooling effect of the through-hole is getting larger. No. with a through-hole diameter / storage battery outer diameter of 0.2. In No. 5, the capacity is reduced by 6%, which can be said to be an allowable limit of the capacity reduction. No. where the diameter of the through hole / the outer diameter of the storage battery is 0.3 out of the range of the present invention. In No. 6, the cooling effect was very good, but the capacity was reduced by 11%, which is a problem in that respect.
[0013]
From the above test results, when the through hole is provided, if the diameter r is set to 0.05R ≦ r ≦ 0.2R with respect to the outer diameter R of the storage battery, the capacity reduction due to the through hole falls within an allowable range, and It was found that a cooling effect was obtained. In particular, when importance is placed on the cooling effect, the difference in capacity between the cylindrical lead storage battery having no through hole and the capacity reduction is about 4% is small, and the through hole diameter / storage battery outer diameter at which the cooling effect is remarkably obtained is 0.1. It can be said that it is preferable
.
Next, the results of a test on the heat radiation effect when a cylindrical storage battery provided with a through hole is used in an assembled battery are shown below.
[Test 2]
Using a cylindrical lead-acid battery having the same rated capacity of 10 Ah as in Test 1, a storage battery provided with through-holes having through-hole diameter / storage battery outer diameter of 0.1 and 0.2 was prepared. A battery pack in which a total of 10 batteries were closely arranged without providing a gap between cells was formed, the same 1CA overcharge test as in Test 1 was performed, and the temperature difference between the cells was measured using a temperature sensor. The test was performed in an atmosphere at 25 ° C. Table 2 shows the test contents and results.
Shown in
[0015]
[Table 2]
As shown in Table 2, in the conventional lead storage battery A without a through-hole, when the cells are closely arranged, the temperature rises due to poor heat dissipation of the center cell, and the cell with the end cell has a poor heat dissipation. The temperature difference was as high as 8 ° C. On the other hand, in the storage battery B of the present invention provided with the through-holes having the ratio of the through-hole diameter / storage battery outer diameter of 0.1, the temperature difference between the cells can be reduced to 4 ° C. In C provided with a through hole, the temperature difference can be suppressed to 2 ° C., and providing a through hole in the storage battery of the present invention is effective in reducing the temperature difference between the storage batteries in the assembled battery. It became clear.
[0017]
In addition, when the battery is used in a place where the environmental temperature is high, the battery may be cooled by blowing air. In this case, if the storage battery is provided with a through hole, the wind passes through the through hole. It was found that the cooling effect was several steps better than that of a storage battery without through holes.
[0018]
【The invention's effect】
As described above, the cylindrical storage battery has a characteristic that, due to its structure, heat generated in the storage battery is easily radiated at a portion facing the side surface of the battery case, but is hardly radiated at a central portion of the storage battery. ing. Therefore, there is a problem that a temperature difference occurs in the storage battery, and the high temperature in the central portion of the storage battery accelerates the deterioration and shortens the service life. Further, in the assembled battery in which a plurality of the single cells (cells) are connected, since the heat radiation characteristics are different between the central cell and the end cells, a temperature difference occurs between the cells, and the high temperature cell limits the storage battery life. I also had problems. On the other hand, when a through hole in the direction of the winding axis of the electrode group is provided in the center of the cylindrical storage battery and the outer diameter of the storage battery is R and the diameter of the through hole is r, 0.05R ≦ r By maintaining the relationship of ≦ 0.2R, the central part of the storage battery is effectively cooled, the temperature difference in the single cell and the temperature difference between the cells in the assembled battery are reduced, and the capacity decrease due to the presence of the through hole is reduced. It can be minimized, has a stable life performance, and has a great industrial effect.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a main part of an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylindrical lead-acid battery 2 Positive electrode terminal 3 Negative terminal 4 Safety valve 5 Through hole
