JP2970422B2 - PTC element - Google Patents
PTC elementInfo
- Publication number
- JP2970422B2 JP2970422B2 JP22129794A JP22129794A JP2970422B2 JP 2970422 B2 JP2970422 B2 JP 2970422B2 JP 22129794 A JP22129794 A JP 22129794A JP 22129794 A JP22129794 A JP 22129794A JP 2970422 B2 JP2970422 B2 JP 2970422B2
- Authority
- JP
- Japan
- Prior art keywords
- ptc element
- powder
- ptc
- battery
- nickel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Thermistors And Varistors (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、電池が短絡された場合
や大電流の充放電による発熱に対する安全性の確保を目
的とした***品として使用されるＰＴＣ素子に関する
ものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PTC element used as a safety component for ensuring safety against short-circuiting of a battery or heat generation due to charging and discharging of a large current.
【０００２】[0002]
【従来の技術】電池が放電されている状態にあっては、
電池内にＱ＝Ｉ2 Ｒｔ〔Ｑ：発熱量（Ｗｈ）、Ｉ：電流
（Ａ）、Ｒ：抵抗（Ω）、ｔ：時間（ｈｒｓ）〕で示さ
れるジュール熱が発生する。この発熱は放電電流が大き
い程大きく、電池部品が損傷を受けたり、場合によって
は大きな焼損に至る危険性を有している。特にニッケル
カドミウム蓄電池、ニッケル水素蓄電池およびリチウム
二次電池など高出力二次電池では短絡時に大電流が流
れ、電池自体の温度が２００℃以上まで上昇する場合が
ある。このため、電池を過度の電流および熱から保護す
るため、正温度係数抵抗素子（以下「ＰＴＣ素子」とい
う）が使用されている。ＰＴＣ素子としてはポリオレフ
ィン系樹脂に導電性粉末としてカーボン粉末を適量混合
したものが一般的に使用されていた。2. Description of the Related Art When a battery is discharged,
Joule heat represented by Q = I 2 Rt [Q: heat value (Wh), I: current (A), R: resistance (Ω), t: time (hrs)] is generated in the battery. This heat is greater as the discharge current is larger, and there is a risk that the battery parts may be damaged or even burned out in some cases. Particularly, in a high-output secondary battery such as a nickel-cadmium storage battery, a nickel-metal hydride storage battery, and a lithium secondary battery, a large current flows during a short circuit, and the temperature of the battery itself may rise to 200 ° C. or more. Therefore, in order to protect the battery from excessive current and heat, a positive temperature coefficient resistance element (hereinafter, referred to as “PTC element”) is used. As the PTC element, a mixture of a polyolefin resin and an appropriate amount of carbon powder as a conductive powder was generally used.
【０００３】この素子の動作原理は定常状態（常温にお
ける定格電流以下での使用状態）ではポリマー中に分散
された導電性の粒子が無数の導電性パスを形成し、低い
固有抵抗値を示すが、この状態から除々に温度を上昇さ
せるとポリマーの熱膨張率が導電性の粒子に比べて高い
ため導電性パスが次第に切断されて少しずつ抵抗値が上
昇するという緩やかなＰＴＣ特性を示す。さらに温度が
上昇し８０℃程度になると急激な抵抗値の上昇、すなわ
ちＰＴＣ効果（トリップ）を示すものである。[0003] The operating principle of this element is that in a steady state (a state of use at a rated current or less at normal temperature), conductive particles dispersed in a polymer form innumerable conductive paths and exhibit a low specific resistance. If the temperature is gradually increased from this state, the thermal expansion coefficient of the polymer is higher than that of the conductive particles, so that the conductive path is gradually cut and the resistance value gradually increases, showing a gradual PTC characteristic. When the temperature further rises to about 80 ° C., the resistance value sharply increases, that is, the PTC effect (trip) is exhibited.
【０００４】通常、電池パックに組み込む場合のＰＴＣ
素子に要求される形状と特性には以下のことがらが要求
される。Normally, PTC when incorporated in a battery pack
The following are required for the shape and characteristics required for the device.
【０００５】１）電池パックの異常負荷（２０℃で２０
Ａ以上）に対し、８秒以内で安全サイドに動作するこ
と。1) Abnormal load of the battery pack (20 at 20 ° C.)
A) or more, within 8 seconds.
【０００６】２）使用中の異常温度（８０℃以上）でト
リップし、電池パックに損傷、変形を起こさせないこ
と。2) The battery pack does not trip at an abnormal temperature (80 ° C. or higher) during use, and does not damage or deform the battery pack.
【０００７】３）直流電圧に対して１５Ｖ以上の耐圧特
性を持っていること。 ４）定常状態で３０ｍΩ以下の低抵抗であること。[0007] 3) Withstand voltage characteristics of 15 V or more with respect to DC voltage. 4) Low resistance of 30 mΩ or less in a steady state.
【０００８】５）信頼性は環境に問題なく電池パックの
寿命まで保証されること。 ６）体積は極力小さいこと。[0008] 5) The reliability is guaranteed for the life of the battery pack without environmental problems. 6) The volume must be as small as possible.
【０００９】これらのことから、従来、導電性の粉末と
してはカーボンが最も多く使用されてきたが、小型化お
よび定常状態における電池への負荷を小さくするために
さらに低抵抗の素子が要求されることから、金属、特に
ニッケルの微粒子が用いられるようになってきた。For these reasons, conventionally, carbon has been most often used as the conductive powder. However, in order to reduce the size and reduce the load on the battery in a steady state, an element having a lower resistance is required. For this reason, fine particles of metal, particularly nickel, have come to be used.
【００１０】[0010]
【発明が解決しようとする課題】しかしながら、金属粉
末を導電性粒子として用いた場合には素子の固有抵抗値
を小さくすることができるが、反面、使用環境（温度、
湿度、腐食性ガス）によって金属粒子が酸化され、固有
抵抗値が大幅に上昇し、電池特性を低下させたりトリッ
プ電流値が異常に小さくなり正常な使用が不可能になる
という問題を有していた。また、製造過程においても大
気中では同様にニッケル粒子が酸化され固有抵抗値が変
化するため材料管理が煩雑になり作業性にも課題があっ
た。However, when the metal powder is used as the conductive particles, the specific resistance of the element can be reduced, but the use environment (temperature,
(Humidity, corrosive gas), the metal particles are oxidized, the specific resistance value rises significantly, the battery characteristics deteriorate, the trip current value becomes abnormally small, and there is a problem that normal use becomes impossible. Was. Also, in the manufacturing process, nickel particles are similarly oxidized in the air and the specific resistance value changes, so that material management is complicated and there is a problem in workability.
【００１１】本発明はＰＴＣ素子の固有抵抗値を金属粉
末を単独で用いる場合に比べて小さくし、さらに高温高
湿においても酸化による固有抵抗値の上昇を抑制し広範
な使用環境において正常な使用を可能とするＰＴＣ素子
を提供することを目的とする。According to the present invention, the specific resistance of the PTC element is reduced as compared with the case where the metal powder is used alone, and an increase in the specific resistance due to oxidation is suppressed even at a high temperature and a high humidity. It is an object of the present invention to provide a PTC element which enables the following.
【００１２】[0012]
【課題を解決するための手段】この目的を達成するため
に、本発明のＰＴＣ素子は、結晶性高分子に導電性粉末
を添加し、混練後、シート状に形成した正抵抗温度係数
発熱体組成物の両面に電極板を圧着したＰＴＣ素子であ
って、前記導電性粉末としての金属粉末の表面を耐酸化
性と導電性とを有する材料で被覆したことを特徴とす
る。In order to achieve this object, a PTC element according to the present invention comprises a positive-resistance temperature coefficient heating element formed by adding a conductive powder to a crystalline polymer, kneading the mixture, and forming a sheet. A PTC element in which an electrode plate is pressure-bonded to both surfaces of a composition, wherein a surface of the metal powder as the conductive powder is coated with a material having oxidation resistance and conductivity.
【００１３】この場合、前記結晶性高分子はポリオレフ
ィン系高分子であることが好ましい。In this case, the crystalline polymer is preferably a polyolefin polymer.
【００１４】また、前記導電性粉末はニッケル粉末であ
ることが好ましい。また、前記耐酸化性と導電性とを有
する材料はパラジウムであることが好ましい。特に、こ
のパラジウムの被覆法が無電解メッキ法であることが好
ましい。It is preferable that the conductive powder is a nickel powder. Further, the material having the oxidation resistance and the conductivity is preferably palladium. In particular, the palladium coating method is preferably an electroless plating method.
【００１５】前記導電性粉末としてはニッケルの他にア
ルミニウム、スズ、コバルト、鉄、銅などが使用でき
る。また、メッキ材料としては、金、銀および白金など
も使用できる。しかし、価格および耐酸化性の面からニ
ッケルとパラジウムの組み合わせが好ましい。この時、
使用するニッケル微粒子の平均粒径は一次粒子で０．５
〜１００ミクロンおよびパラジウムのメッキ量は重量比
で５％以上で充分効果を示すが、メッキ量は価格の面よ
り５〜１０％の範囲が適当である。As the conductive powder, besides nickel, aluminum, tin, cobalt, iron, copper and the like can be used. Further, gold, silver, platinum and the like can be used as the plating material. However, a combination of nickel and palladium is preferred in terms of cost and oxidation resistance. At this time,
The average particle size of the nickel fine particles used is 0.5 in primary particles.
Although the plating amount of palladium of ~ 100 microns and palladium is more than 5% by weight, a sufficient effect is obtained, but the plating amount is suitably in the range of 5-10% from the viewpoint of price.
【００１６】[0016]
【作用】上記構成によって、導電性粉末の酸化還元電位
が貴な方向に大幅にシフトするため、高温高湿の環境中
においても安定した抵抗値を維持でき、電池特性を低下
させることなく、かつ安全装置として誤動作を防ぐこと
ができるものである。According to the above construction, the oxidation-reduction potential of the conductive powder is largely shifted in a noble direction, so that a stable resistance value can be maintained even in a high-temperature and high-humidity environment, and the battery characteristics are not deteriorated. As a safety device, malfunction can be prevented.
【００１７】[0017]
【実施例】以下本発明の実施例について図面を参照しな
がら説明する。Embodiments of the present invention will be described below with reference to the drawings.
【００１８】図１にＰＴＣ素子の概形を示す。１はＰＴ
Ｃチップであり、２は電極端子板である。FIG. 1 shows an outline of a PTC element. 1 is PT
C is a chip, and 2 is an electrode terminal plate.
【００１９】先ず導電体として全金属量の１０重量％の
パラジウムを無電解メッキした平均粒径１５ミクロンの
ニッケル粉末を８６重量％、中密度ポリエチレンを１
３．５重量％、有機酸化防止剤粉末イルガノックス１０
３５（日本チバガイギー社製）を０．５重量％の比率で
混合し、その混合物を押し出し成型機で厚み２．０ｍｍ
のＰＴＣシートに成形した後、５．５×１４ｍｍのチッ
プに切断し、両面に電極端子板として厚み１００ミクロ
ンのニッケル板を熱圧着し本発明の実施例によるＰＴＣ
素子を作成した。First, as an electric conductor, 86% by weight of nickel powder having an average particle diameter of 15 μm and a medium density polyethylene of 1% by weight were electrolessly plated with 10% by weight of palladium of the total metal as a conductor.
3.5% by weight, organic antioxidant powder Irganox 10
35 (manufactured by Nippon Ciba Geigy) at a ratio of 0.5% by weight, and the mixture was extruded to a thickness of 2.0 mm with an extruder.
After cutting into 5.5 × 14 mm chips, a 100 μm thick nickel plate as an electrode terminal plate is thermocompression bonded on both sides to form a PTC sheet according to an embodiment of the present invention.
A device was created.
【００２０】次に、導電体として用いるニッケル粉末に
パラジウムメッキを施さない他は、前記実施例と全く同
様にして従来例によるＰＴＣ素子を作製した。Next, a PTC element according to a conventional example was manufactured in exactly the same manner as in the above embodiment except that palladium plating was not applied to nickel powder used as a conductor.
【００２１】図２に示すように実施例と従来例によるＰ
ＴＣ素子各々４０ヶずつについて、それらの抵抗値を測
定し、度数分布で比較した。As shown in FIG. 2, P according to the embodiment and the prior art
The resistance value of each of the 40 TC elements was measured and compared by frequency distribution.
【００２２】この図から明らかなように、本実施例によ
るＰＴＣ素子の初期抵抗値は従来例のＰＴＣ素子より低
く、かつそのバラツキも縮小しており特性の向上が認め
られる。As can be seen from the figure, the initial resistance value of the PTC element according to the present embodiment is lower than that of the conventional PTC element, and its variation is reduced, so that an improvement in the characteristics is recognized.
【００２３】また、図３に示すように本実施例と従来例
によるＰＴＣ素子の各々について直流電圧（１５Ｖ）が
負荷された実用状態で高温高湿雰囲気（４５℃−９０％
ＲＨ）中に保存したときの抵抗値の経時変化をプロット
した。As shown in FIG. 3, each of the PTC elements according to the present embodiment and the conventional example is in a high-temperature and high-humidity atmosphere (45 ° C.-90%) in a practical state in which a DC voltage (15 V) is loaded.
The change with time of the resistance value when stored in (RH) was plotted.
【００２４】この図から明らかなように、本実施例によ
るＰＴＣ素子では高温高湿雰囲気でも、従来例のような
抵抗値の増加は見られず、過酷な使用環境においても優
れた信頼性を有することが分かる。As is apparent from this figure, the PTC element according to the present embodiment does not show an increase in the resistance value as in the conventional example even in a high-temperature and high-humidity atmosphere, and has excellent reliability even in a severe use environment. You can see that.
【００２５】[0025]
【発明の効果】以上のように本発明によれば導電体とし
て用いる金属粉末の表面を耐酸化性と導電性とを有する
材料で被覆することにより、このように被覆しない状態
で使用した場合に比べ初期の抵抗値が低く、かつそのバ
ラツキも小さいＰＴＣ素子を提供することができる。As described above, according to the present invention, the surface of a metal powder used as a conductor is coated with a material having oxidation resistance and conductivity, so that the metal powder can be used without such a coating. A PTC element having a lower initial resistance value and a smaller variation can be provided.
【００２６】さらに、本発明によるＰＴＣ素子は過酷な
使用環境においても抵抗変化が小さく、***品として
の信頼性を大幅に向上させることができる。Further, the PTC element according to the present invention has a small resistance change even in a severe use environment, and can greatly improve the reliability as a safety component.
【図１】本発明によるＰＴＣ素子の概形を示す斜視図FIG. 1 is a perspective view showing an outline of a PTC element according to the present invention.
【図２】ＰＴＣ素子の抵抗値についての度数分布を示す
図FIG. 2 is a diagram showing a frequency distribution with respect to a resistance value of a PTC element;
【図３】ＰＴＣ素子の抵抗値の経時変化を示す図FIG. 3 is a diagram showing a change over time in a resistance value of a PTC element;
１ ＰＴＣチップ ２ 電極端子板 1 PTC chip 2 Electrode terminal plate
フロントページの続き (72)発明者 永江 澄男 大阪府門真市大字門真1006番地 松下電 器産業株式会社内 (56)参考文献 特開 平５−21208（ＪＰ，Ａ) 特開 昭63−302501（ＪＰ，Ａ) 特開 平３−166701（ＪＰ，Ａ) 特表 平５−508055（ＪＰ，Ａ) (58)調査した分野(Int.Cl.6，ＤＢ名) H01C 7/02- 7/22 Continuation of the front page (72) Inventor Sumio Nagae 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (56) References JP-A-5-21208 (JP, A) JP-A-63-302501 (JP) JP-A-3-166701 (JP, A) JP-A-5-508055 (JP, A) (58) Fields investigated (Int. Cl. 6 , DB name) H01C 7 / 02-7 / 22
Claims (3)
練後、シート状に形成した正抵抗温度係数発熱体組成物
の両面に電極板を圧着したＰＴＣ素子であって、前記導
電性粉末としての金属粉末の表面に、前記金属粉末に対
して５〜１０重量％のパラジウムを無電解メッキして被
覆したＰＴＣ素子。1. A PTC element comprising a crystalline polymer, a conductive powder added to the polymer, kneading, and electrode plates pressed on both surfaces of a sheet-shaped positive resistance temperature coefficient heating element composition, The surface of the metal powder as a powder is
A PTC element covered by electroless plating with 5 to 10% by weight of palladium .
分子である請求項１記載のＰＴＣ素子。2. The PTC element according to claim 1, wherein the crystalline polymer is a polyolefin-based polymer.
求項１または２記載のＰＴＣ素子。3. The PTC element according to claim 1, wherein said conductive powder is nickel powder.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22129794A JP2970422B2 (en) | 1994-09-16 | 1994-09-16 | PTC element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22129794A JP2970422B2 (en) | 1994-09-16 | 1994-09-16 | PTC element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0888106A JPH0888106A (en) | 1996-04-02 |
| JP2970422B2 true JP2970422B2 (en) | 1999-11-02 |
Family
ID=16764586
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22129794A Expired - Fee Related JP2970422B2 (en) | 1994-09-16 | 1994-09-16 | PTC element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2970422B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4803880B2 (en) * | 2001-01-11 | 2011-10-26 | 三洋電機株式会社 | Pack battery |
| JP2006164826A (en) * | 2004-12-09 | 2006-06-22 | Sanyo Electric Co Ltd | Battery pack |
| US20100015522A1 (en) * | 2005-05-16 | 2010-01-21 | Takashi Hasunuma | Sealing piece and battery pack using the same |
| KR100686844B1 (en) * | 2005-07-25 | 2007-02-26 | 삼성에스디아이 주식회사 | Secondary battery with ptc device |
-
1994
- 1994-09-16 JP JP22129794A patent/JP2970422B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0888106A (en) | 1996-04-02 |
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| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |