JP4082506B2

JP4082506B2 - Battery pack manufacturing method

Info

Publication number: JP4082506B2
Application number: JP2003157999A
Authority: JP
Inventors: 孝志隅田
Original assignee: Hitachi Maxell Energy Ltd
Current assignee: Hitachi Maxell Energy Ltd
Priority date: 2003-06-03
Filing date: 2003-06-03
Publication date: 2008-04-30
Anticipated expiration: 2023-06-03
Also published as: JP2004358735A

Description

【０００１】
【発明の属する技術分野】
本発明は、角箱状の素電池を金型のキャビティに装着し、キャビティに溶融樹脂を注入して素電池の外周側面に樹脂モールドを一体成形する電池パックの製造方法に関する。
【０００２】
【従来の技術】
特許文献１−３では、素電池に電装品が仮組み付設された中間組立品をつくり、この中間組立品を成形金型のキャビティに装着し、キャビティに溶融樹脂を注入して樹脂モールドを成形し、樹脂モールドで素電池に電装品を一体化した電池パックを製造することが開示されている。
【０００３】
そこでは、図１０に示すごとく成形金型２２に中間組立品１７の外周側面に接触作用する複数の位置決め突起２４を設けておき、成形金型２２のキャビティ２３に中間組立品１７を位置決め突起２４で位置決め装着している。
【０００４】
【特許文献１】
特開２００３−１７０２２号公報（段落番号００２８−００３０、図９−１２）
【特許文献２】
特開２００３−７７４３４号公報（段落番号００３０−００３２、図９−１０）
【特許文献３】
特開２００３−７７４３６号公報（段落番号００２５、図８）
【０００５】
【発明が解決しようとする課題】
しかし、図１０に示す従来の位置決め突起２４は、キャビティ２３の周側面につながっていたので、成形金型２２から抜き出した製品電池パックをみたとき、樹脂モールド２に位置決め突起２４による凹みが生じ、該当の凹み部分において電池パックの絶縁性が損われやすかった。該当の凹み部分の存在は、外観上の体裁を悪くし、強度的にも部分的に劣る不利を招いていた。
【０００６】
そこで従来は、樹脂モールドの成形後に電池パックの全体を熱収縮チューブで被覆して絶縁するなどしているが、熱収縮チューブが存在する分だけ電池パックが分厚くなるうえ、熱収縮チューブを電池パックに被せて熱収縮させる工程が増えて電池パックの製造に手間が掛かっていた。
【０００７】
そこで本発明の目的は、位置決め突起による抜き穴が樹脂モールドの外周側面に凹み形成されることがなく、従って電池パックの全体を熱収縮チューブで被覆せずとも、簡単確実に絶縁被覆できる電池パックの製造方法を得ることにある。
【０００８】
【課題を解決するための手段】
本発明は、これの内容を実施例に従って具体的に説明すると、図１および図２に示すごとく、角箱状の素電池１の外周側面に電装品を仮組み付設した中間組立品１７をつくり、成形金型２２のキャビティ２３に中間組立品１７を装着し、キャビティ２３に溶融樹脂を充填して、素電池１の外周側面に前記電装品を樹脂モールド２で一体化する電池パックの製造方法である。
【０００９】
電装品は、外部出力端子１４・１５を外部に臨ませるための窓口１９・２０が貫通状に設けられた帯板状の保護カバー１８を備えており、この保護カバー１８は、素電池１の前方に配されている。成形金型２２には、図５に示すごとく中間組立品１７の上下面に臨むキャビティ２３の上下面の少なくとも一方に、中間組立品１７の左右面部分に接触作用する位置決め突起２４と、中間組立品１７の後面部分に接触作用する位置決め突起２４とを設けておく。しかるときは、キャビティ２３に中間組立品１７を装着したとき、各位置決め突起２４の内側面２５が中間組立品１７の左面部分、右面部分および後面部分に接触するとともに、キャビティ２３の前面部分２３ｂが保護カバー１８の前面に接触することで、中間組立品１７の前後および左右方向の位置決めが図られる。各位置決め突起２４は、横断平面視で長方形の角形を呈しており、該長方形の長辺となる内側面２５が、中間組立品１７に対する接触面となっている。各位置決め突起２４の突端内縁には傾斜案内面が形成されている。そして、キャビティ２３に溶融樹脂を注入すると、各位置決め突起２４と中間組立品１７の外周側面に対向するキャビティ２３の周側面との間の隙間２６に溶融樹脂が回り込むようにしたものである。
もしくは、成形金型２２には、図９に示すごとく中間組立品１７の上下面に臨むキャビティ２３の上下面の少なくとも一方に、中間組立品１７の右面部分に接触作用する位置決め突起２４と、中間組立品１７の後面部分に接触作用する位置決め突起２４とを設けておく。しかるときは、キャビティ２３に中間組立品１７を装着したとき、各位置決め突起２４の内側面２５が中間組立品１７の右面部分および後面部分に接触するとともに、キャビティ２３の左側面部分２３ｃが中間組立品１７の左面部分に接触し、さらに、キャビティ２３の前面部分２３ｂが保護カバー１８の前面に接触することで、中間組立品１７の前後および左右方向の位置決めが図られる。
【００１０】
電池パックＰの絶縁のために、前記成形金型２２から取り出した電池パックＰの扁平な上下面に、絶縁材２７を被覆し、各位置決め突起２４の存在箇所において前記樹脂モールド２に生じた抜き穴２８を前記絶縁材２７で塞いでいる。ここでの絶縁材２７としては、紙やプラスチックなどで形成されたラベルシートや、絶縁性の塗膜や、印刷インキ層や、合成樹脂層などが該当する。
【００１１】
【発明の作用効果】
本発明方法によれば、成形金型２２のキャビティ２３に中間組立品１７を装着したとき、中間組立品１７の外周側面に位置決め突起２４が接触作用して、キャビティ２３内において中間組立品１７を位置決め保持する。これで素電池１および電装品の少なくとも外周側面が樹脂モールド２で覆われて、素電池１に電装品が一体化される。
【００１２】
その際、成形金型２２における各位置決め突起２４の存在部位に注目すると、各位置決め突起２４と、中間組立品１７の外周側面に対向するキャビティ２３の周側面との間には隙間２６が形成されているので、この隙間２６に溶融樹脂が回り込む。つまり、樹脂モールド２の成形時に溶融樹脂が各位置決め突起２４を包み込んだ状態になる。その結果、成形金型２２を開いて製品・電池パックＰを取り出したとき、樹脂モールド２の内部には各位置決め突起２４の存在痕として抜き穴２８が空洞状に生じる。この抜き穴２８は樹脂モールド２の横外側方からは認められない。従って、樹脂モールド２による絶縁性および強度を有効に図ることができる。
【００１３】
但し、成形金型２２の下型２２ａにのみ前記位置決め突起２４を設けたとき、樹脂モールド２には、抜き穴２８の下端が開口状態にある。位置決め突起２４の上端が上型２２ｂの内面に達して当接しているときは、抜き穴２８の上端も開口状態になる。そこで、成形金型２２を開いて取り出した製品・電池パックＰの扁平な上下面に絶縁材２７を被覆し、抜き穴２８の開口を塞ぐことにより、更に確実に絶縁被覆できる。これによれば、電池パックＰの全体を熱収縮チューブなどで被覆する従来形態とは異なり、電池パックＰの上下厚みなどを小さくでき、また電池パックの製造の手間を軽減できて安価に量産できる。
【００１４】
【発明の実施の形態】
（実施例１）図２は本発明の実施例１の製造方法で得られる電池パックＰを示しており、扁平角箱状の素電池１と、この素電池１の外周側面に付設される電装品と、素電池１に電装品を一体化する樹脂モールド２とからなる。
【００１５】
素電池１は、図３に示すごとく、上下面が実質的に平坦面に形成されており、上下厚み寸法が小さくて前後方向に長い長方形の扁平角箱状になっている。素電池１は、上下厚み寸法が５mm、前後寸法が４８mm、左右寸法が３０mmである。
【００１６】
樹脂モールド２は、前記電装品と素電池１の上下面を除く外周側面とを覆っている。樹脂モールド２は、ポリアミド樹脂、スチレン系エラストマ樹脂およびエチレン・酢酸ビニル（ＥＶＡ）系やポリウレタン（ＰＵＲ）系のホットメルト樹脂などの熱可塑性樹脂で成形される。
【００１７】
図３において素電池１は、外装缶４の内部に電極体と電解液とを封入した充放電が可能な２次電池、例えばリチウムイオン電池からなり、外装缶４の前面を塞ぐ封口板５の中央に正極端子６を備えている。外装缶４はニッケル板やアルミニウム板などを深絞り加工して形成してあり、それ自体が負極側の出力端子を兼ねる。前記電極体はＬｉＣｏＯ₂ を活物質とする正極シートと、黒鉛を活物質とする負極シートとをセパレーターを挟んで渦巻状に巻回し、全体を扁平に押し潰し形成してある。
【００１８】
電装品は、素電池１の前面側に配置される保護回路モジュール７と、素電池１の後面側に配置されるポリスイッチ８とを含み、これら両者７・８および先の正極端子６と保護回路モジュール７とをそれぞれ接続する長短２種のリード線９・１０を備えている。
【００１９】
保護回路モジュール７は、保護回路などを内部に配置した左右方向に長い長方形状になっており、左右両端から後ろ向きに帯状の接続リード１２・１３がそれぞれ導出されている。保護回路モジュール７は、ポリカーボネート樹脂やアクリロニトリル・ブタジエン・スチレン（ＡＢＳ）樹脂などのプラスチック成形品からなる。
【００２０】
前記接続リード１２・１３は、前記保護回路などに接続されている。保護回路は、素電池１の過放電や過充電を防止する。保護回路モジュール７の前面外側には、正極側の外部出力端子１４と、負極側の外部出力端子１５とが配設されている。
【００２１】
ポリスイッチ８は、素電池１の温度が設定値を越える場合に素電池１の電流を遮断するために設けてあり、その一端に接続リード１６を有する。保護回路モジュール７およびポリスイッチ８の上下厚み寸法は、素電池１の厚み寸法よりわずかに小さく設定してある。リード線９・１０および接続リード１２・１３・１６は、それぞれ銅あるいはアルミニウムなどの導電性金属の薄シートを帯状に切断して形成してあり、その上下幅寸法は保護回路モジュール７の上下厚み寸法より小さく設定してある。
【００２２】
上記のようにして素電池１の外周側面に前記電装品を仮組み付設して、図４の中間組立品１７をつくる。電装品は、別に保護カバー１８を備えている。この保護カバー１８は、保護回路モジュール７の前面外側に配置する。保護カバー１８は、左右方向に長い帯板状のプラスチック成形品からなり、図３に示すごとく、保護回路モジュール７の正負の外部出力端子１４・１５を外部に臨ませるための窓口１９・２０が貫通状に設けられている。外部出力端子１４・１５が各窓口１９・２０にそれぞれ嵌り込む状態で、保護カバー１８を保護回路モジュール７の外側前面に貼り付けることにより中間組立品１７をつくる。
【００２３】
詳しくは、保護回路モジュール７の左右の接続リード１２・１３に、短いリード線１０と長いリード線９とをそれぞれスポット溶接し、さらに長いリード線９の後端にポリスイッチ８の接続リード１６をスポット溶接して、電装品をひとつながりにする。
【００２４】
次に、短いリード線１０を封口板５に絶縁性の両面テープを介して貼り付けたのち、正極端子６にスポット溶接する。同様に、長いリード線９を絶縁性の両面テープを介して素電池１の横側面に貼り付け、さらにポリスイッチ８を素電池１の後側面に絶縁性の両面テープを介して貼り付け、その貼着面を外装缶４にスポット溶接する。
【００２５】
これにより、前記中間組立品１７が完成する。この中間組立品１７を射出成形装置によってインサート成形することで、素電池１に電装品を樹脂モールド２で一体化する。
【００２６】
図５および図６は、樹脂モールド２を形成するための成形金型２２を示す。この成形金型２２は、下型２２ａと上型２２ｂとを含み、上下型２２ａ・２２ｂを合わせた内部に形成したキャビティ２３に、中間組立品１７が位置決め突起２４で位置決め装着される。
【００２７】
中間組立品１７の下面に臨むキャビティ２３の下面２３ａ、すなわち下型２２ａの内底面には、中間組立品１７の外周側面に接触作用する複数の位置決め突起２４がそれぞれ上向きに突設されている。具体的には、図５に示すごとく中間組立品１７の外周側面の左右面部分に接触作用する位置決め突起２４をそれぞれ前後に２個ずつ設け、中間組立品１７の外周側面の後面部分に接触作用する位置決め突起２４を１個設けてある。
【００２８】
後ろ側の位置決め突起２４の内側面２５は、ポリスイッチ８から外れた左側方において素電池１の後側面に接触する。中間組立品１７の右側方に配置した前後の位置決め突起２４の内側面２５は、それぞれ長いリード線９の外側に接触する。中間組立品１７の左側方に配置した位置決め突起２４の内側面２５は、素電池１の左側面に直に接触する。
【００２９】
左右の位置決め突起２４は、キャビティ２３内における中間組立品１７の左右方向の位置決めを図る。後ろ側の位置決め突起２４は中間組立品１７の後方への移動限界を位置決めする。保護カバー１８の外側前面をキャビティ２３の周側面の前面部分２３ｂに当接させることで、中間組立品１７の前方への移動を位置決め規制している。中間組立品１７の上下面には、キャビティ２３の上下面が密着し、これにて中間組立品１７の上下方向の位置決めが図られる。
【００３０】
各位置決め突起２４は、図５に示すごとく横断平面視で長方形の角形を呈しており、長辺が３〜４mm、短辺が0.５mm、突出高さが2.５mmである。各位置決め突起２４は、図６に示すごとく、長辺となる内側面２５が中間組立品１７の外周側面に接触作用する。
【００３１】
各位置決め突起２４の上端内縁は傾斜案内面に形成されており、下型２２ａのキャビティ２３に中間組立品１７を上方から落とし込み装着するとき、該傾斜案内面で中間組立品１７の外側面が位置決め突起２４の内側面２５に接するようガイドされる。
【００３２】
本発明において注目すべきは、各位置決め突起２４と、中間組立品１７の外周側面に対向するキャビティ２３の周側面との間に、溶融樹脂が流動し得る隙間２６が形成されている点にある。この隙間２６の幅寸法は0.５mmに設定した。
【００３３】
樹脂モールド２の成形に際しては、下型２２ａのキャビティ２３に中間組立品１７を位置決め装着したのち、下型２２ａに上型２２ｂを型締めして、キャビティ２３に溶融樹脂を注入する。溶融樹脂の注入圧力は、１〜１０ＭＰａ、より好ましくは、１〜５ＭＰａの範囲に設定する。前記溶融樹脂の温度は２００℃程度に設定した。
【００３４】
下型２２ａ内に前記中間組立品１７を装着した状態において、中間組立品１７は、キャビティ２３内に前述の要領で位置決めされているので、溶融樹脂の注入で中間組立品１７が前後・左右に位置ズレすることはない。保護カバー１８の外側前面と、キャビティ２３の周側面の前面部分２３ｂとの間にも溶融樹脂が入り込むことはなく、保護回路モジュール７の窓口１９・２０が溶融樹脂で塞がれることがない。
【００３５】
溶融樹脂は前記隙間２６に回り込む。従って、溶融樹脂が固化したのち、電池パックＰを成形金型２２から取り出したとき、樹脂モールド２の外周側面に位置決め突起２４の介在による縦長の凹みが外部に露出する状態で形成されることを阻止し、この凹みを介して素電池１の外装缶４やリード線９などが、電池パックＰの外周側面において外部に露出することを防いでいる。
【００３６】
この後に、図２に示すごとく電池パックＰの扁平な上下面に絶縁シート製のラベルからなる絶縁材２７をそれぞれ貼り付けて、電池パックＰの上下面の全体を絶縁材２７で絶縁被覆する。電池パックＰの樹脂モールド２の内部には、図７に示すごとく、各位置決め突起２４の存在部位において下面が開口する抜き穴２８が空洞状に生じている。この各抜き穴２８は前記絶縁材２７で密閉状に塞がれる。従って、前記抜き穴２８を介して素電池１の外装缶４やリード線９などが外部に露出することはない。
【００３７】
かくして、電池パックＰの外周面の全体が、樹脂モールド２および絶縁材２７・２７で余すところなく全面的に被覆される。
【００３８】
（実施例２）図８および図９は本発明の実施例２を示しており、これでは樹脂モールド２が素電池１の外周側面のうち、前側面部分、後側面部分および右側面部分を覆うコ字状に成形されている。この場合の位置決め突起２４は、図９に示すごとく中間組立品１７の外周側面の右側面部分と、後側面部分とにそれぞれ１個ずつ配設した。他は実施例１と同じであり、同じ部材には同じ符号を付して説明を省略する。
【００３９】
但し、実施例２では、中間組立品１７の外周側面の左側面部分をキャビティ２３の周側面の左側面部分２３ｃに直に当接させることで左右方向の位置決めを図っている。
【００４１】
実施例１において、位置決め突起２４は、少なくとも中間組立品１７の外周側面の左右側面部分にそれぞれ１個ずつ設けられていてもよい。同様に実施例２において、位置決め突起２４は、中間組立品１７の外周側面の右側面部分の前後に２個配してあってもよい。つまり、位置決め突起２４の個数は任意に選択できる。
【００４２】
各位置決め突起２４は、実施例の上型２２ｂ側にも設けることができる。先の絶縁材２７は、ラベルシートに代えて、電池パックＰの上下面に印刷層や塗膜などを施す形態にしてもよい。
【００４３】
先の保護回路は実施例で説明した機能を持つものに限定されず、電池パックＰの用途に応じて必要な回路に構成することができる。
【図面の簡単な説明】
【図１】本発明を原理的に説明する概略平面図
【図２】実施例１の電池パックの斜視図
【図３】素電池と電装品との分解斜視図
【図４】中間組立品の斜視図
【図５】実施例１の成形金型に中間組立品を装填した状態での横断平面図
【図６】図５におけるＢ−Ｂ線断面図
【図７】図２におけるＡ−Ａ線断面図
【図８】実施例２の電池パックの斜視図
【図９】実施例２の成形金型に中間組立品を装填した状態での横断平面図
【図１０】従来公知例を原理的に説明する概略平面図
【符号の説明】
１素電池
２樹脂モールド
１４・１５外部出力端子
１７中間組立品
１８保護カバー
２２成形金型
２２ａ下型
２２ｂ上型
２３キャビティ
２４位置決め突起
２５位置決め突起の内側面
２６隙間
２７絶縁材
２８抜き穴
Ｐ電池パック[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a battery pack in which a rectangular box-shaped unit cell is mounted in a cavity of a mold, a molten resin is injected into the cavity, and a resin mold is integrally formed on the outer peripheral side surface of the unit cell.
[0002]
[Prior art]
In Patent Documents 1-3, an intermediate assembly in which electrical components are temporarily assembled to a unit cell is manufactured, the intermediate assembly is mounted in a cavity of a molding die, and a molten resin is injected into the cavity to form a resin mold. And manufacturing the battery pack which integrated the electrical component with the unit cell with the resin mold is disclosed.
[0003]
In this case, as shown in FIG. 10, a plurality of positioning protrusions 24 that contact the outer peripheral side surface of the intermediate assembly 17 are provided on the molding die 22, and the intermediate assembly 17 is positioned in the cavity 23 of the molding die 22. Positioned and mounted with.
[0004]
[Patent Document 1]
Japanese Patent Laying-Open No. 2003-17022 (paragraph numbers 0028-0030 and FIGS. 9-12)
[Patent Document 2]
Japanese Patent Laying-Open No. 2003-77434 (paragraph numbers 0030-0032, FIGS. 9-10)
[Patent Document 3]
Japanese Patent Laying-Open No. 2003-77436 (paragraph number 0025, FIG. 8)
[0005]
[Problems to be solved by the invention]
However, since the conventional positioning protrusion 24 shown in FIG. 10 is connected to the peripheral side surface of the cavity 23, when the product battery pack extracted from the molding die 22 is viewed, the resin mold 2 has a recess due to the positioning protrusion 24. The insulation of the battery pack was likely to be damaged at the corresponding recess. The presence of the corresponding dent portion deteriorates the appearance of the appearance, and causes a disadvantage that the strength is partially inferior.
[0006]
Therefore, conventionally, after the resin mold is molded, the entire battery pack is covered with a heat-shrinkable tube and insulated. However, the battery pack becomes thicker as much as the heat-shrinkable tube is present, and the heat-shrinkable tube is replaced with a battery pack. The process of heat shrinking over the cover increased, and it took time to manufacture the battery pack.
[0007]
Accordingly, an object of the present invention is to provide a battery pack in which a punch hole by a positioning projection is not formed in a concave shape on the outer peripheral side surface of the resin mold, and therefore the battery pack can be easily and securely insulated without being covered with a heat shrinkable tube. It is to obtain a manufacturing method.
[0008]
[Means for Solving the Problems]
The present invention will be described in detail according to the embodiment. As shown in FIGS. 1 and 2, an intermediate assembly 17 in which electrical components are temporarily assembled on the outer peripheral side surface of the rectangular box-shaped unit cell 1 is manufactured. The battery pack is manufactured by mounting the intermediate assembly 17 in the cavity 23 of the molding die 22, filling the cavity 23 with molten resin, and integrating the electrical components on the outer peripheral side surface of the unit cell 1 with the resin mold 2. It is.
[0009]
The electrical component includes a strip-shaped protective cover 18 in which windows 19 and 20 for exposing the external output terminals 14 and 15 to the outside are provided in a penetrating manner. It is arranged in the front. As shown in FIG. 5, the molding die 22 has at least one of the upper and lower surfaces of the cavity 23 facing the upper and lower surfaces of the intermediate assembly 17, positioning protrusions 24 that act on the left and right surface portions of the intermediate assembly 17, and the intermediate assembly. A positioning projection 24 that contacts the rear surface portion of the product 17 is provided. Accordingly, when the intermediate assembly 17 is mounted in the cavity 23, the inner side surface 25 of each positioning projection 24 contacts the left surface portion, the right surface portion, and the rear surface portion of the intermediate assembly 17, and the front surface portion 23 b of the cavity 23 is By contacting the front surface of the protective cover 18, the intermediate assembly 17 can be positioned in the front-rear and left-right directions. Each positioning projection 24 has a rectangular square shape in a cross-sectional plan view, and an inner side surface 25 which is a long side of the rectangular shape is a contact surface with respect to the intermediate assembly 17. An inclined guide surface is formed on the inner edge of each positioning projection 24. When the molten resin is injected into the cavity 23, the molten resin goes around the gap 26 between each positioning projection 24 and the peripheral side surface of the cavity 23 facing the outer peripheral side surface of the intermediate assembly 17.
Alternatively, as shown in FIG. 9, the molding die 22 has a positioning protrusion 24 that contacts the right surface portion of the intermediate assembly 17 on at least one of the upper and lower surfaces of the cavity 23 facing the upper and lower surfaces of the intermediate assembly 17, and an intermediate Positioning protrusions 24 that contact the rear surface of the assembly 17 are provided. In this case, when the intermediate assembly 17 is mounted in the cavity 23, the inner side surface 25 of each positioning projection 24 contacts the right side portion and the rear side portion of the intermediate assembly 17, and the left side portion 23c of the cavity 23 is in the intermediate assembly. Positioning of the intermediate assembly 17 in the front-rear and left-right directions is achieved by contacting the left surface portion of the product 17 and the front surface portion 23 b of the cavity 23 contacting the front surface of the protective cover 18.
[0010]
In order to insulate the battery pack P, the flat upper and lower surfaces of the battery pack P taken out from the molding die 22 are covered with an insulating material 27, and the resin mold 2 is removed at each location of the positioning protrusions 24. The hole 28 is closed with the insulating material 27. Here, the insulating material 27 corresponds to a label sheet formed of paper, plastic or the like, an insulating coating film, a printing ink layer, a synthetic resin layer, or the like.
[0011]
[Effects of the invention]
According to the method of the present invention, when the intermediate assembly 17 is mounted in the cavity 23 of the molding die 22, the positioning projection 24 contacts the outer peripheral side surface of the intermediate assembly 17, and the intermediate assembly 17 is moved in the cavity 23. Hold the positioning. Thus, at least the outer peripheral side surfaces of the unit cell 1 and the electrical component are covered with the resin mold 2, and the electrical component is integrated with the unit cell 1.
[0012]
At this time, when attention is paid to the location of each positioning projection 24 in the molding die 22, a gap 26 is formed between each positioning projection 24 and the peripheral side surface of the cavity 23 facing the outer peripheral side surface of the intermediate assembly 17. As a result, the molten resin wraps around the gap 26. That is, when the resin mold 2 is molded, the molten resin wraps around the positioning protrusions 24. As a result, when the molding die 22 is opened and the product / battery pack P is taken out, a hollow 28 is formed in the resin mold 2 as a trace of each positioning protrusion 24 in a hollow shape. This punched hole 28 is not recognized from the lateral outer side of the resin mold 2. Therefore, insulation and strength by the resin mold 2 can be effectively achieved.
[0013]
However, when the positioning protrusion 24 is provided only on the lower mold 22a of the molding die 22, the lower end of the punch hole 28 is in an open state in the resin mold 2. When the upper end of the positioning projection 24 reaches and contacts the inner surface of the upper mold 22b, the upper end of the punch hole 28 is also in an open state. Therefore, by covering the flat upper and lower surfaces of the product / battery pack P taken out by opening the molding die 22 with the insulating material 27 and closing the opening of the punch hole 28, the insulating coating can be more reliably performed. According to this, unlike the conventional form in which the entire battery pack P is covered with a heat-shrinkable tube or the like, the thickness of the battery pack P can be reduced, and the labor of manufacturing the battery pack can be reduced, so that it can be mass-produced at low cost. .
[0014]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1) FIG. 2 shows a battery pack P obtained by the manufacturing method of Embodiment 1 of the present invention, and a flat square box-shaped unit cell 1 and electrical equipment attached to the outer peripheral side surface of the unit cell 1 And a resin mold 2 for integrating electrical components with the unit cell 1.
[0015]
As shown in FIG. 3, the unit cell 1 has a substantially flat flat upper and lower surface, and has a rectangular flat box shape with a small vertical thickness and a long front and rear direction. The unit cell 1 has a vertical thickness dimension of 5 mm, a longitudinal dimension of 48 mm, and a lateral dimension of 30 mm.
[0016]
The resin mold 2 covers the electrical component and the outer peripheral side surface excluding the upper and lower surfaces of the unit cell 1. The resin mold 2 is formed of a thermoplastic resin such as a polyamide resin, a styrene elastomer resin, and an ethylene / vinyl acetate (EVA) or polyurethane (PUR) hot melt resin.
[0017]
In FIG. 3, the unit cell 1 is a secondary battery capable of charging and discharging, for example, a lithium ion battery, in which an electrode body and an electrolytic solution are enclosed in an outer can 4, and a sealing plate 5 that closes the front surface of the outer can 4. A positive electrode terminal 6 is provided in the center. The outer can 4 is formed by deep-drawing a nickel plate, an aluminum plate, or the like, and itself serves as an output terminal on the negative electrode side. The electrode body is formed by winding a positive electrode sheet using LiCoO ₂ as an active material and a negative electrode sheet using graphite as an active material in a spiral shape with a separator interposed therebetween, and flatly crushing the whole.
[0018]
The electrical component includes a protection circuit module 7 disposed on the front side of the unit cell 1 and a polyswitch 8 disposed on the rear side of the unit cell 1, and protects both of them 7 and 8 and the positive electrode terminal 6. Two types of long and short lead wires 9 and 10 for connecting the circuit module 7 are provided.
[0019]
The protection circuit module 7 has a rectangular shape that is long in the left-right direction with a protection circuit and the like disposed therein, and strip-shaped connection leads 12 and 13 are led out from both left and right ends, respectively. The protection circuit module 7 is made of a plastic molded product such as polycarbonate resin or acrylonitrile / butadiene / styrene (ABS) resin.
[0020]
The connection leads 12 and 13 are connected to the protection circuit and the like. The protection circuit prevents overdischarge or overcharge of the unit cell 1. Outside the front surface of the protection circuit module 7, a positive-side external output terminal 14 and a negative-side external output terminal 15 are disposed.
[0021]
The polyswitch 8 is provided to cut off the current of the unit cell 1 when the temperature of the unit cell 1 exceeds a set value, and has a connection lead 16 at one end thereof. The upper and lower thickness dimensions of the protection circuit module 7 and the polyswitch 8 are set slightly smaller than the thickness dimension of the unit cell 1. The lead wires 9 and 10 and the connecting leads 12, 13 and 16 are each formed by cutting a thin sheet of conductive metal such as copper or aluminum into a strip shape, and the vertical width is the vertical thickness of the protection circuit module 7. It is set smaller than the dimensions.
[0022]
As described above, the electrical component is temporarily attached to the outer peripheral side surface of the unit cell 1 to produce the intermediate assembly 17 shown in FIG. The electrical component is provided with a protective cover 18 separately. The protective cover 18 is disposed outside the front surface of the protective circuit module 7. The protective cover 18 is formed of a strip-shaped plastic molded product that is long in the left-right direction. As shown in FIG. 3, as shown in FIG. It is provided in a penetrating manner. The intermediate assembly 17 is made by attaching the protective cover 18 to the outer front surface of the protective circuit module 7 in a state where the external output terminals 14 and 15 are fitted in the windows 19 and 20, respectively.
[0023]
Specifically, the short lead wire 10 and the long lead wire 9 are spot welded to the left and right connection leads 12 and 13 of the protection circuit module 7 respectively, and the connection lead 16 of the polyswitch 8 is attached to the rear end of the longer lead wire 9. Spot welding to connect electrical components together.
[0024]
Next, the short lead wire 10 is attached to the sealing plate 5 via an insulating double-sided tape, and then spot-welded to the positive electrode terminal 6. Similarly, a long lead wire 9 is attached to the lateral side surface of the unit cell 1 via an insulating double-sided tape, and a polyswitch 8 is further attached to the rear side surface of the unit cell 1 via an insulating double-sided tape. The sticking surface is spot welded to the outer can 4.
[0025]
Thereby, the intermediate assembly 17 is completed. The intermediate assembly 17 is insert-molded by an injection molding apparatus, so that the electrical component is integrated into the unit cell 1 with the resin mold 2.
[0026]
5 and 6 show a molding die 22 for forming the resin mold 2. The molding die 22 includes a lower die 22a and an upper die 22b, and the intermediate assembly 17 is positioned and mounted by positioning protrusions 24 in a cavity 23 formed inside the upper and lower dies 22a and 22b.
[0027]
A plurality of positioning projections 24 that contact the outer peripheral side surface of the intermediate assembly 17 project upward from the lower surface 23a of the cavity 23 facing the lower surface of the intermediate assembly 17, that is, the inner bottom surface of the lower mold 22a. Specifically, as shown in FIG. 5, two positioning protrusions 24 that contact and act on the left and right side portions of the outer peripheral side surface of the intermediate assembly 17 are provided on the front and rear sides, respectively, and the rear surface portion of the outer peripheral side surface of the intermediate assembly 17 is contacted. One positioning projection 24 is provided.
[0028]
The inner side surface 25 of the rear positioning protrusion 24 contacts the rear side surface of the unit cell 1 on the left side away from the polyswitch 8. The inner side surfaces 25 of the front and rear positioning protrusions 24 arranged on the right side of the intermediate assembly 17 are in contact with the outer sides of the long lead wires 9, respectively. The inner side surface 25 of the positioning protrusion 24 arranged on the left side of the intermediate assembly 17 is in direct contact with the left side surface of the unit cell 1.
[0029]
The left and right positioning protrusions 24 position the intermediate assembly 17 in the left-right direction in the cavity 23. The rear positioning protrusion 24 positions the rearward movement limit of the intermediate assembly 17. By positioning the outer front surface of the protective cover 18 against the front surface portion 23b on the peripheral side surface of the cavity 23, the forward movement of the intermediate assembly 17 is regulated. The upper and lower surfaces of the cavity 23 are in close contact with the upper and lower surfaces of the intermediate assembly 17, whereby the intermediate assembly 17 is positioned in the vertical direction.
[0030]
As shown in FIG. 5, each positioning protrusion 24 has a rectangular square shape in a cross-sectional plan view, and has a long side of 3 to 4 mm, a short side of 0.5 mm, and a protruding height of 2.5 mm. As shown in FIG. 6, each positioning protrusion 24 has a long side inner surface 25 that contacts the outer peripheral side surface of the intermediate assembly 17.
[0031]
The upper end inner edge of each positioning projection 24 is formed as an inclined guide surface, and when the intermediate assembly 17 is dropped into the cavity 23 of the lower mold 22a from the upper side and mounted, the outer surface of the intermediate assembly 17 is positioned by the inclined guide surface. Guided to contact the inner surface 25 of the protrusion 24.
[0032]
It should be noted in the present invention that a gap 26 through which the molten resin can flow is formed between each positioning protrusion 24 and the peripheral side surface of the cavity 23 facing the outer peripheral side surface of the intermediate assembly 17. . The width dimension of the gap 26 was set to 0.5 mm.
[0033]
When molding the resin mold 2, the intermediate assembly 17 is positioned and mounted in the cavity 23 of the lower mold 22 a, and then the upper mold 22 b is clamped to the lower mold 22 a and molten resin is injected into the cavity 23. The injection pressure of the molten resin is set in the range of 1 to 10 MPa, more preferably 1 to 5 MPa. The temperature of the molten resin was set to about 200 ° C.
[0034]
In the state where the intermediate assembly 17 is mounted in the lower mold 22a, the intermediate assembly 17 is positioned in the cavity 23 as described above, so that the intermediate assembly 17 is moved back and forth and left and right by injection of molten resin. There is no misalignment. The molten resin does not enter between the outer front surface of the protective cover 18 and the front surface portion 23b on the peripheral side surface of the cavity 23, and the windows 19 and 20 of the protective circuit module 7 are not blocked by the molten resin.
[0035]
The molten resin goes around the gap 26. Therefore, when the battery pack P is taken out from the molding die 22 after the molten resin is solidified, a vertically long recess is formed on the outer peripheral side surface of the resin mold 2 with the positioning protrusions 24 exposed to the outside. The outer can 4 and the lead wire 9 of the unit cell 1 are prevented from being exposed to the outside on the outer peripheral side surface of the battery pack P through the recess.
[0036]
Thereafter, as shown in FIG. 2, an insulating material 27 made of a label made of an insulating sheet is attached to the flat upper and lower surfaces of the battery pack P, and the entire upper and lower surfaces of the battery pack P are covered with the insulating material 27. In the resin mold 2 of the battery pack P, as shown in FIG. 7, a hollow 28 is formed in a hollow shape whose lower surface is open at a portion where each positioning protrusion 24 is present. Each of the holes 28 is sealed with the insulating material 27 in a sealed manner. Therefore, the outer can 4 and the lead wire 9 of the unit cell 1 are not exposed to the outside through the punched hole 28.
[0037]
Thus, the entire outer peripheral surface of the battery pack P is entirely covered with the resin mold 2 and the insulating materials 27 and 27.
[0038]
(Example 2) FIGS. 8 and 9 show Example 2 of the present invention, in which the resin mold 2 covers the front side part, the rear side part, and the right side part of the outer peripheral side surface of the unit cell 1. Shaped in a U shape. In this case, one positioning protrusion 24 is provided on each of the right side surface portion and the rear side surface portion of the outer peripheral side surface of the intermediate assembly 17 as shown in FIG. Others are the same as those of the first embodiment, and the same members are denoted by the same reference numerals and description thereof is omitted.
[0039]
However, in the second embodiment, the left-side surface portion of the outer peripheral side surface of the intermediate assembly 17 is directly brought into contact with the left-side surface portion 23c of the peripheral side surface of the cavity 23, thereby achieving the left-right positioning.
[0041]
In the first embodiment, one positioning protrusion 24 may be provided on each of the left and right side portions of the outer peripheral side surface of the intermediate assembly 17. Similarly, in the second embodiment, two positioning protrusions 24 may be arranged before and after the right side surface portion of the outer peripheral side surface of the intermediate assembly 17. That is, the number of positioning protrusions 24 can be arbitrarily selected.
[0042]
Each positioning protrusion 24 can also be provided on the upper mold 22b side of the embodiment. Instead of the label sheet, the insulating material 27 may have a form in which a printed layer, a coating film, or the like is applied to the upper and lower surfaces of the battery pack P.
[0043]
The previous protection circuit is not limited to the one having the function described in the embodiment, and can be configured as a necessary circuit according to the use of the battery pack P.
[Brief description of the drawings]
FIG. 1 is a schematic plan view for explaining the present invention in principle. FIG. 2 is a perspective view of a battery pack of Example 1. FIG. 3 is an exploded perspective view of a unit cell and electrical components. FIG. 5 is a cross-sectional plan view in a state where an intermediate assembly is loaded in the molding die of Example 1. FIG. 6 is a cross-sectional view taken along line BB in FIG. 5. FIG. FIG. 8 is a perspective view of the battery pack of Example 2. FIG. 9 is a cross-sectional plan view of the molding die of Example 2 loaded with an intermediate assembly. FIG. Outline plan to explain 【Explanation of symbols】
DESCRIPTION OF SYMBOLS 1 Unit cell 2 Resin mold 14/15 External output terminal 17 Intermediate assembly 18 Protective cover 22 Molding die 22a Lower die 22b Upper die 23 Cavity 24 Positioning projection 25 Positioning projection 25 Inner side surface 26 Gap 27 Insulating material 28 Punch hole P pack

Claims

The electrical component on the outer peripheral side surface of the corner box-shaped unit cell creates a temporary assembly attached to the intermediate assembly, the intermediate assembly to the molding die cavity mounting, by filling the molten resin into the cavity, of the unit cell in the method for manufacturing a battery pack that integrated with the outer circumferential surface of the electrical component in the resin mold,
The electrical component is provided with a strip-shaped protective cover provided with a window for penetrating the external output terminal to the outside, and the protective cover is arranged in front of the unit cell,
Wherein the molding die, at least one of the upper and lower surfaces of said cavity facing the upper and lower surfaces of the intermediate assembly, the positioning protrusion in contact acting on the left and right side portions of the intermediate assembly, the rear surface portion of the intermediate assembly And positioning protrusions that contact,
When the intermediate assembly is mounted in the cavity, the inner surface of each positioning protrusion contacts the left surface portion, the right surface portion, and the rear surface portion of the intermediate assembly, and the front surface portion of the cavity is on the front surface of the protective cover. By contacting, the intermediate assembly is positioned in the front-rear and left-right directions,
Each of the positioning protrusions has a rectangular shape in a cross-sectional plan view, and an inner side surface that is a long side of the rectangle is a contact surface with respect to the intermediate assembly,
An inclined guide surface is formed on the inner edge of the protruding end of each positioning protrusion,
When injecting the molten resin into the cavity, the battery pack characterized by a-law write around the molten resin into the gap between the peripheral surface of the cavity opposite the to the outer periphery side of each positioning projection and said intermediate assembly Production method.

An intermediate assembly in which electrical components are temporarily assembled on the outer peripheral side surface of the square box-shaped unit cell is manufactured, the intermediate assembly is mounted in the cavity of the molding die, and the molten resin is filled in the cavity. In the battery pack manufacturing method in which the electrical component is integrated with a resin mold on the outer peripheral side surface,
The electrical component is provided with a strip-shaped protective cover provided with a window for penetrating the external output terminal to the outside, and the protective cover is arranged in front of the unit cell,
The mold includes at least one of the upper and lower surfaces of the cavity facing the upper and lower surfaces of the intermediate assembly, a positioning protrusion that contacts the right surface portion of the intermediate assembly, and a rear surface portion of the intermediate assembly. And positioning protrusions that contact,
When the intermediate assembly is mounted in the cavity, the inner surface of each positioning protrusion comes into contact with the right surface portion and the rear surface portion of the intermediate assembly, and the left side surface portion of the cavity is in contact with the left surface portion of the intermediate assembly. In addition, the front portion of the cavity is in contact with the front surface of the protective cover, so that the intermediate assembly is positioned in the front-rear and left-right directions,
Each of the positioning protrusions has a rectangular shape in a cross-sectional plan view, and an inner side surface that is a long side of the rectangle is a contact surface with respect to the intermediate assembly,
An inclined guide surface is formed on the inner edge of the protruding end of each positioning protrusion,
A method of manufacturing a battery pack, wherein when molten resin is injected into the cavity, the molten resin wraps around a gap between each positioning projection and the peripheral side surface of the cavity facing the outer peripheral side surface of the intermediate assembly. .

The flat upper and lower surfaces of the battery pack taken out from the molding die are covered with an insulating material, and a hole formed in the resin mold is closed with the insulating material at each location of the positioning protrusions. The manufacturing method of the battery pack of description.