JP2001345094A - Method of testing active material mixture for positive electrode - Google Patents

Method of testing active material mixture for positive electrode

Info

Publication number
JP2001345094A
JP2001345094A JP2000164188A JP2000164188A JP2001345094A JP 2001345094 A JP2001345094 A JP 2001345094A JP 2000164188 A JP2000164188 A JP 2000164188A JP 2000164188 A JP2000164188 A JP 2000164188A JP 2001345094 A JP2001345094 A JP 2001345094A
Authority
JP
Japan
Prior art keywords
positive electrode
active material
material mixture
electrode active
separator
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.)
Abandoned
Application number
JP2000164188A
Other languages
Japanese (ja)
Inventor
Katsunori Suzuki
克典 鈴木
Koji Higashimoto
晃二 東本
Tomohiro Iguchi
智博 井口
Kensuke Hironaka
健介 弘中
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Resonac Corp
Original Assignee
Shin Kobe Electric Machinery Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Shin Kobe Electric Machinery Co Ltd filed Critical Shin Kobe Electric Machinery Co Ltd
Priority to JP2000164188A priority Critical patent/JP2001345094A/en
Publication of JP2001345094A publication Critical patent/JP2001345094A/en
Abandoned legal-status Critical Current

Links

Classifications

    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50Manufacturing or production processes characterised by the final manufactured product

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  • Secondary Cells (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

PROBLEM TO BE SOLVED: To provide a method of testing an active material mixture for positive electrode, by which presence of foreign metals in the active material mixture for positive electrode can be proved with ease and certainty. SOLUTION: A positive electrode plate 1 on which an active material mixture for positive electrode has been coated, and a negative electrode plate 2 are opposed to each other through a separator 3 and immersed in an electrolyte, and predetermined voltage is applied between the positive electrode plate 1 and the negative electrode plate 2 to forcedly deposit foreign metals such as Fe and Cu in the positive electrode active material mixture on the separator. When foreign metals are mixed into the layer of the active material mixture for the positive electrode, black spots are visually observed on the separator 3 even when the mixed amount is 1 ppm or so. The black spots are separated from the separator 3 and subjected to elementary analysis, whereby the foreign metals are identified.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【発明の属する技術分野】本発明は正極活物質合剤の検
査方法に係り、特に、リチウムイオンを吸蔵・放出可能
な正極活物質とこの正極活物質を結着させる結着剤とを
含有する正極活物質合剤中の異種金属の有無を判別する
正極活物質合剤の検査方法に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting a positive electrode active material mixture, and more particularly, to a method for containing a positive electrode active material capable of absorbing and releasing lithium ions and a binder for binding the positive electrode active material. The present invention relates to a method for testing a positive electrode active material mixture for determining the presence or absence of a different metal in a positive electrode active material mixture.

【0002】[0002]

【従来の技術】リチウムイオン電池は高エネルギー密度
であるメリットを活かして、主にVTRカメラやノート
型パソコン、携帯電話などのポータブル機器に使用され
ている。また、近年は電気自動車用や電力貯蔵用を目的
とする、大型のリチウムイオン電池の研究開発も活発に
行われている。特に、自動車産業界においては環境問題
に対応すべく、動力源としてモータを用いる方式の電気
自動車や、動力源として内燃機関とモータとの両方を用
いるハイブリッド方式の電気自動車の開発が進められて
おり、その一部はすでに実用化されている。
2. Description of the Related Art Lithium ion batteries are mainly used for portable devices such as VTR cameras, notebook computers, and mobile phones, taking advantage of the high energy density. In recent years, research and development of large-sized lithium-ion batteries for electric vehicles and power storage have been actively conducted. In particular, in the automotive industry, development of electric vehicles that use a motor as a power source and hybrid electric vehicles that use both an internal combustion engine and a motor as a power source are being promoted in order to respond to environmental issues. Some of them are already in practical use.

【0003】これら電気自動車等に使用される大型のリ
チウムイオン電池には、高容量、高出力という特性と同
時に安全性、信頼性が強く要求されている。しかしなが
ら、従来のリチウムイオン電池では、正極活物質合剤中
に含まれる異種金属イオン(Fe、Cu等)が電解液中
に溶出し、充放電により、負極側でデントライト成長し
て析出し、しいては正負極間の内部短絡を引き起こす場
合も認められた。
[0003] Large lithium ion batteries used in these electric vehicles and the like are required to have high capacity and high output, as well as safety and reliability. However, in the conventional lithium ion battery, the foreign metal ions (Fe, Cu, etc.) contained in the positive electrode active material mixture elute into the electrolytic solution, grow and precipitate on the negative electrode side by charge and discharge, and precipitate. In some cases, an internal short circuit between the positive and negative electrodes was caused.

【0004】これらの析出物となる異種金属は、正極活
物質合剤層中に10ppm未満の濃度で存在しても内部
短絡を引き起こす原因となるため、正極に用いる原材料
の選別が重要である。このため、従来はICP分析(In
ductively Coupled Plasma analysis)等により、正極
活物質合剤中に異種金属が混入していないかの検査を行
っていた。
[0004] Since these different metals, which are precipitates, cause an internal short circuit even if present in a concentration of less than 10 ppm in the positive electrode active material mixture layer, it is important to select raw materials used for the positive electrode. For this reason, conventional ICP analysis (In
Inductively-coupled plasma analysis) or the like was used to check whether a different metal was mixed in the positive electrode active material mixture.

【0005】[0005]

【発明が解決しようとする課題】しかしながら、ICP
分析では、正極活物質合剤中にFe、Cu等の異種金属
が含まれていても、含有量が微少であるため分析限界値
近傍となり、明確に異種金属が混入されているかが分か
らなかった。このため、実際の電池製作後に異種金属の
混入が判明し、電池作製の歩留りを落とす、という問題
があった。また、経時に従って電池は充放電が繰り返さ
れ異種金属が負極側に徐々に析出するので、リチウムイ
オン電池の信頼性を確保する上でも不良原因を未然に防
ぐ必要がある。
SUMMARY OF THE INVENTION However, the ICP
In the analysis, even if a different metal such as Fe or Cu was contained in the positive electrode active material mixture, the content was very small, so it was near the analysis limit, and it was not clear whether the different metal was mixed. . For this reason, there has been a problem that mixing of different metals has been found after the actual battery production, and the yield of battery production has been reduced. In addition, the battery is repeatedly charged and discharged with time, and the dissimilar metal is gradually deposited on the negative electrode side. Therefore, in order to ensure the reliability of the lithium ion battery, it is necessary to prevent the cause of the defect beforehand.

【0006】本発明は上記問題に鑑み、正極活物質合剤
中の異種金属の有無を簡易かつ明確に判別することがで
きる正極活物質合剤の検査方法を提供することを課題と
する。
SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a method for inspecting a positive electrode active material mixture that can easily and clearly determine the presence or absence of a different metal in the positive electrode active material mixture.

【0007】[0007]

【課題を解決するための手段】上記課題を解決するため
に本発明は、リチウムイオンを吸蔵・放出可能な正極活
物質とこの正極活物質を結着させる結着剤とを含有する
正極活物質合剤中の異種金属の有無を判別する正極活物
質合剤の検査方法であって、前記正極活物質合剤を塗布
した正極と、負極と、をセパレータを介して対向させて
電解液中に浸潤させ、前記正極及び負極間に所定電圧を
印加して前記正極活物質合剤中の異種金属を前記セパレ
ータ上に黒点として強制的に析出させることを特徴とす
る。
SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a positive electrode active material containing a positive electrode active material capable of inserting and extracting lithium ions and a binder for binding the positive electrode active material. A method for testing a positive electrode active material mixture for determining the presence or absence of a dissimilar metal in a mixture, wherein the positive electrode coated with the positive electrode active material mixture and the negative electrode are opposed to each other with a separator therebetween in an electrolytic solution. And injecting a predetermined voltage between the positive electrode and the negative electrode to forcibly precipitate different metals in the positive electrode active material mixture as black spots on the separator.

【0008】本発明では、リチウムイオンを吸蔵・放出
可能な正極活物質とこの正極活物質を結着させる結着剤
とを含有する正極活物質合剤を塗布した正極と、負極
と、をセパレータを介して対向させて電解液中に浸潤さ
せ、正極及び負極間に所定電圧を印加する。正極活物質
合剤中に異種金属が混入されていると、該異種金属はセ
パレータ上に黒点として強制的に析出される。本発明に
よれば、異種金属がセパレータ上に黒点として強制的に
析出されるので、セパレータ上の黒点を目視することに
より、正極活物質合剤中に異種金属が混入されているか
の有無を簡易かつ明確に判別することができる。
In the present invention, a positive electrode coated with a positive electrode active material mixture containing a positive electrode active material capable of occluding and releasing lithium ions and a binder for binding the positive electrode active material, and a negative electrode are separated by a separator. To infiltrate into the electrolytic solution while facing each other, and apply a predetermined voltage between the positive electrode and the negative electrode. If a different metal is mixed in the positive electrode active material mixture, the different metal is forcibly precipitated as a black spot on the separator. According to the present invention, since dissimilar metals are forcibly precipitated as black spots on the separator, by visually observing the black spots on the separator, it is easy to determine whether the dissimilar metals are mixed in the positive electrode active material mixture. And it can be clearly distinguished.

【0009】この場合において、析出した黒点を元素分
析する工程を更に含むようにすれば、正極活物質合剤中
の異種金属を特定することができるので、正極活物質合
剤を構成する材料のうち当該異種金属を有する材料の特
定が容易となる。
In this case, if the method further includes a step of performing an elemental analysis of the deposited black spots, it is possible to identify a different metal in the positive electrode active material mixture, so that the material constituting the positive electrode active material mixture can be identified. Of these, the material having the dissimilar metal can be easily specified.

【0010】[0010]

【発明の実施の形態】以下、図面を参照して本発明に係
る正極活物質合剤の検査方法の実施の形態について説明
する。
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a method for testing a positive electrode active material mixture according to the present invention will be described with reference to the drawings.

【0011】<正極板の作製>正極用活物質であるマン
ガン酸リチウム(LiMnO)粉末と、導電剤とし
て鱗片状黒鉛(平均粒径:20μm)と、結着剤として
ポリフッ化ビニリデン(PVDF)とを、質量比で9
0:4.5:5.5の割合で混合し、この混合物に分散
溶媒としてN−メチル−2−ピロリドン(NMP)を添
加した後、混練してスラリを作製した。このスラリを、
厚さ20μmのアルミニウム箔(正極集電体)の片面に
塗布して正極活物質合剤層とした。
<Preparation of Positive Electrode> Lithium manganate (LiMn 2 O 4 ) powder as a positive electrode active material, flaky graphite (average particle size: 20 μm) as a conductive agent, and polyvinylidene fluoride (Binylidene fluoride) as a binder PVDF) in a mass ratio of 9
The mixture was mixed at a ratio of 0: 4.5: 5.5, N-methyl-2-pyrrolidone (NMP) was added as a dispersion solvent to the mixture, and the mixture was kneaded to prepare a slurry. This slurry,
It was applied on one side of a 20 μm-thick aluminum foil (positive electrode current collector) to form a positive electrode active material mixture layer.

【0012】図1(A)に示すように、スラリの塗布の
際には、アルミニウム箔の長寸方向に対して、側縁の一
方に幅30mmの未塗布部分を残した。その後、乾燥、
プレス、裁断して側縁の未塗布部分を残したうえ、合剤
塗布部の幅を100mm、長さ100mmとした正極板
1を得た。なお、正極活物質合剤層の厚さ(ただし、ア
ルミニウム箔の厚さは含まない)を120μm、アルミ
ニウム箔片面あたりの正極活物質塗布量を344g/m
とした。正極板1に形成した30mmの未塗布部の一
部を除去し、幅10mm、長さ30mmの正極集電リー
ド片11とした。
As shown in FIG. 1A, when the slurry was applied, an uncoated portion having a width of 30 mm was left on one of the side edges in the longitudinal direction of the aluminum foil. Then drying,
The positive electrode plate 1 having a width of 100 mm and a length of 100 mm was obtained after pressing and cutting to leave an uncoated portion of the side edge. The thickness of the positive electrode active material mixture layer (excluding the thickness of the aluminum foil) was 120 μm, and the coating amount of the positive electrode active material per one side of the aluminum foil was 344 g / m 2.
And 2 . A part of the 30 mm uncoated portion formed on the positive electrode plate 1 was removed to obtain a positive electrode current collecting lead piece 11 having a width of 10 mm and a length of 30 mm.

【0013】<負極板の作製>負極用活物質として、非
晶質炭素であるカーボトロンP(商品名:呉羽化学工業
株式会社製)90質量部に、結着剤として10質量部の
ポリフッ化ビニリデンを添加し、これに分散溶媒のN−
メチル−2−ピロリドンを添加後、混練してスラリを作
製した。このスラリを、厚さ10μmの圧延銅箔(負極
集電体)の片面に塗布した。
<Preparation of Negative Electrode Plate> 90 parts by mass of Carbotron P (product name: manufactured by Kureha Chemical Industry Co., Ltd.) which is amorphous carbon as an active material for a negative electrode, and 10 parts by mass of polyvinylidene fluoride as a binder Is added thereto, and N-
After adding methyl-2-pyrrolidone, the mixture was kneaded to prepare a slurry. This slurry was applied to one side of a rolled copper foil (negative electrode current collector) having a thickness of 10 μm.

【0014】図1(B)に示すように、スラリの塗布の
際には、銅箔の長寸方向に対して、側縁の一方に幅30
mmの未塗布部を残した。その後乾燥、プレス、裁断し
て幅105mm、長さ105mmとした負極板2を得
た。負極活物質合剤層のかさ密度は約1.0g/cm
とした。負極板2に形成した幅30mmの未塗布部の一
部を除去し、幅10mm、長さ30mmの負極集電リー
ド片21とした。
As shown in FIG. 1 (B), when the slurry is applied, the width 30 is applied to one of the side edges in the longitudinal direction of the copper foil.
mm was left uncoated. Thereafter, drying, pressing and cutting were performed to obtain a negative electrode plate 2 having a width of 105 mm and a length of 105 mm. The bulk density of the negative electrode active material mixture layer is about 1.0 g / cm 3
And A part of the 30 mm wide uncoated portion formed on the negative electrode plate 2 was removed to obtain a negative electrode current collecting lead piece 21 having a width of 10 mm and a length of 30 mm.

【0015】<電極組立>図2に示すように、作製した
正極板1及び負極板2それぞれの活物質合剤塗布側を、
リチウムイオンが通過可能なポリエチレン製セパレータ
3を介して対向させ、テフロン(登録商標)製の容器4
の下蓋42側に配置し、下蓋42に電解液を5cc注液
して正極板1、負極板2及びセパレータ3を電解液に浸
潤させた。その後、EPDM製のOリング5を介在さ
せ、容器4の上蓋41で覆って簡易セルを組み立てた。
上蓋41にはアルミニウム製のネジ6及び銅製のネジ7
がそれぞれ螺挿されており、これらのネジ6、7を回す
ことにより先端部が、それぞれ正極集電リード片11、
負極集電リード片12に確実に接触するようにした。
<Electrode Assembly> As shown in FIG. 2, each of the prepared positive electrode plate 1 and negative electrode plate 2 was coated with the active material mixture,
A Teflon (registered trademark) container 4 is opposed to the separator 4 through a polyethylene separator 3 through which lithium ions can pass.
5 cc of the electrolytic solution was injected into the lower cover 42 to infiltrate the positive electrode plate 1, the negative electrode plate 2 and the separator 3 into the electrolytic solution. Thereafter, a simple cell was assembled by covering the container 4 with the upper lid 41 with an O-ring 5 made of EPDM interposed therebetween.
The upper cover 41 has an aluminum screw 6 and a copper screw 7
Are screwed respectively, and by turning these screws 6 and 7, the tip ends are respectively connected to the positive current collecting lead pieces 11 and
The negative electrode current collecting lead piece 12 was surely brought into contact.

【0016】電解液には、エチレンカーボネート(E
C)、ジメチルカーボネート(DMC)、ジエチルカー
ボネート(DEC)を体積比1:1:1の混合溶液中へ
6フッ化リン酸リチウム(LiPF)を1モル/リッ
トル溶解した有機電解液を用いた。
The electrolytic solution includes ethylene carbonate (E
C) An organic electrolyte obtained by dissolving lithium hexafluorophosphate (LiPF 6 ) at a mole ratio of 1 mol / L in a mixed solution of dimethyl carbonate (DMC) and diethyl carbonate (DEC) at a volume ratio of 1: 1: 1 was used. .

【0017】<電圧印加>次に、作製した簡易セルのネ
ジ6、7間に、50mAの電流で4.2V、3時間充電
し、50mAの電流で2.5Vまで放電させ、更に50
mA、4.2Vで3時間充電した後、24時間放置し
た。
<Voltage Application> Next, between the screws 6 and 7 of the fabricated simple cell, the battery was charged at a current of 50 mA at 4.2 V for 3 hours, discharged at a current of 50 mA to 2.5 V, and further discharged at 50 V.
After charging for 3 hours at mA and 4.2V, the battery was left for 24 hours.

【0018】<解体検査>24時間放置後、簡易セルを
解体しセパレータ3上の黒点の有無を観察した。正極活
物質合剤層中にFe、Cu等の異種金属が混入されてい
れば、セパレータ3上には異種金属が黒点として強制的
に析出される。従って、目視によりセパレータ3上に黒
点を認めると、正極活物質中に異種金属が混入されてい
ることが分かる。
<Disassembly inspection> After standing for 24 hours, the simple cell was disassembled and the presence or absence of black spots on the separator 3 was observed. If different metals such as Fe and Cu are mixed in the positive electrode active material mixture layer, the different metals are forcibly precipitated as black spots on the separator 3. Therefore, when a black spot is visually recognized on the separator 3, it is understood that a foreign metal is mixed in the positive electrode active material.

【0019】更に、黒点部をセパレータ3から分離し、
元素分析を行うことによりその異種金属が特定される。
Further, the black spots are separated from the separator 3,
The dissimilar metal is specified by performing elemental analysis.

【0020】[0020]

【実施例】次に、上記実施形態に従って異種金属の有無
の判定を行った実施例について説明する。
Next, a description will be given of an example in which the presence or absence of a dissimilar metal is determined according to the above embodiment.

【0021】(実施例1)実施例1では、下表1に示す
ように、Feが混入されている正極活物質合剤を塗布し
た正極板1と、負極板2とを、セパレータ3を介して組
み立て、簡易セルとした。なお、本実施例では、意図的
に異種金属であるFeを1.0ppm正極合剤層中に混
入させた。
Example 1 In Example 1, as shown in Table 1 below, a positive electrode plate 1 coated with a positive electrode active material mixture in which Fe was mixed, and a negative electrode plate 2 were interposed with a separator 3 interposed therebetween. And assembled to form a simple cell. In this example, 1.0 ppm of Fe, which is a dissimilar metal, was intentionally mixed into the positive electrode mixture layer.

【0022】[0022]

【表1】 [Table 1]

【0023】(実施例2)実施例2では、表1に示すよ
うに、Cuが混入されている正極活物質合剤を塗布した
正極板1と、負極板2とを、セパレータ3を介して組み
立て、簡易セルとした。なお、本実施例では、意図的に
異種金属であるCuを1.0ppm正極合剤層中に混入
させた。
(Example 2) In Example 2, as shown in Table 1, a positive electrode plate 1 coated with a positive electrode active material mixture containing Cu and a negative electrode plate 2 were interposed with a separator 3 interposed therebetween. Assembled into a simple cell. In this example, Cu, which is a dissimilar metal, was intentionally mixed into the positive electrode mixture layer at 1.0 ppm.

【0024】(実施例3)実施例3では、表1に示すよ
うに、Crが混入されているおそれのある正極活物質合
剤を塗布した正極板1と、負極板2とを、セパレータ3
を介して組み立て、簡易セルとした。
Example 3 In Example 3, as shown in Table 1, a positive electrode plate 1 coated with a positive electrode active material mixture in which Cr was likely to be mixed, and a negative electrode plate 2 were separated by a separator 3
And assembled into a simple cell.

【0025】(実施例4)実施例4では、表1に示すよ
うに、異種金属が混入されていない正極活物質合剤を塗
布した正極板1と、負極板2とを、セパレータ3を介し
て組み立て、簡易セルとした。
(Example 4) In Example 4, as shown in Table 1, a positive electrode plate 1 coated with a positive electrode active material mixture containing no dissimilar metal was mixed with a negative electrode plate 2 with a separator 3 interposed therebetween. And assembled to form a simple cell.

【0026】<試験>次に、以上のように作製した実施
例の各簡易セルについて、上述した電圧印加及び解体検
査を行った。なお、本試験では、24時間放置後に(解
体検査前に)各簡易セルの電圧を測定した。
<Test> Next, the above-described voltage application and disassembly inspection were performed on each simple cell of the embodiment fabricated as described above. In this test, the voltage of each simple cell was measured after standing for 24 hours (before the dismantling inspection).

【0027】下表2に試験結果を示す。Table 2 below shows the test results.

【0028】[0028]

【表2】 [Table 2]

【0029】(評価)表1及び表2に示すように、正極
活物質合剤中に1ppm程度の異種金属を混入させた実
施例1、2の簡易セルは、セパレータ3上に黒点を生
じ、電圧低下を招いた。この黒点は、充放電によりC
u、Feが負極板2に析出したものであり、元素分析の
結果、実施例1にFe、実施例2にCuが検出された。
また、実施例3の簡易セルでも、セパレータ3上に黒点
が認められ、この黒点部の元素分析よりCrが検出され
た。しかしながら、実施例1、2、3の正極活物質合剤
についてICP分析も行ったが、Fe、Cu、Crの明
確な検出はできなかった。
(Evaluation) As shown in Tables 1 and 2, the simple cells of Examples 1 and 2 in which about 1 ppm of a different metal was mixed in the positive electrode active material mixture produced black spots on the separator 3, This caused a voltage drop. This black spot is caused by charging and discharging
u and Fe were deposited on the negative electrode plate 2. As a result of elemental analysis, Fe was detected in Example 1 and Cu was detected in Example 2.
Also, in the simple cell of Example 3, black spots were observed on the separator 3, and Cr was detected by elemental analysis of the black spots. However, although the ICP analysis was also performed on the positive electrode active material mixtures of Examples 1, 2, and 3, Fe, Cu, and Cr could not be clearly detected.

【0030】また、実施例4の簡易セルは24時間放置
後の電圧低下を起こさず、セパレータにも黒点は無い。
セパレータ3上の黒点の有無と24時間経過後の簡易セ
ルの電圧とには一定の関係がある。すなわち、電圧低下
をきたす簡易セルはセパレータ3上に黒点が認められる
ので、電圧測定を行わずに黒点を観察することにより簡
易セルの電圧の低下を推定することができる。
The simple cell of Example 4 did not cause a voltage drop after standing for 24 hours, and the separator had no black spots.
There is a certain relationship between the presence or absence of a black spot on the separator 3 and the voltage of the simple cell after 24 hours. That is, since a black point is recognized on the separator 3 in the simple cell which causes a voltage drop, the voltage drop of the simple cell can be estimated by observing the black point without performing the voltage measurement.

【0031】以上のように本実施形態では、異種金属が
セパレータ3上に黒点として強制的に析出されるので、
セパレータ3上の黒点を目視することにより、正極活物
質合剤中に異種金属が混入されているかの有無を簡易か
つ明確に判別することができる。また、黒点部をセパレ
ータ3から分離し、元素分析を行うことによりその異種
金属を特定することができるので、異種金属を有する正
極側材料の特定を容易に行うことができる。
As described above, in this embodiment, the dissimilar metal is forcibly precipitated as black spots on the separator 3,
By visually observing the black spots on the separator 3, it is possible to easily and clearly determine whether or not a different metal is mixed in the positive electrode active material mixture. In addition, since the different metal can be specified by separating the black spot from the separator 3 and performing elemental analysis, it is possible to easily specify the positive electrode side material having the different metal.

【0032】従って、リチウムイオン電池の不良原因を
未然に防ぐことができるので、電池作製の歩留りを向上
させることができると共に、充放電の繰り返しによる異
種金属の負極側への析出も防止することができるので、
リチウムイオン電池の信頼性を高めることができる。
Accordingly, the cause of the failure of the lithium ion battery can be prevented beforehand, so that the yield of the battery can be improved, and the precipitation of the dissimilar metal on the negative electrode side due to repeated charge and discharge can be prevented. So you can
The reliability of the lithium ion battery can be improved.

【0033】なお、本実施形態では、正極活物質として
マンガン酸リチウムを用いた例を示したが、リチウム・
コバルト複合酸化物やリチウム・ニッケル複合酸化物な
ど、リチウム遷移金属複酸化物一般の正極活物質合剤中
の異種金属の混入の有無を判別することができる。
In this embodiment, an example is shown in which lithium manganate is used as the positive electrode active material.
It is possible to determine the presence or absence of the incorporation of a different metal in the general positive electrode active material mixture such as a cobalt composite oxide and a lithium-nickel composite oxide.

【0034】また、本実施形態では、負極用活物質とし
て非晶質炭素を用いた例を示したが、天然黒鉛、人造黒
鉛、コークスなどの炭素材料、金属Li等も使用でき、
それらの粒子形状においても特に制限されるものではな
い。
In this embodiment, an example in which amorphous carbon is used as the negative electrode active material has been described. However, carbon materials such as natural graphite, artificial graphite, and coke, and metal Li can also be used.
The shape of the particles is not particularly limited.

【0035】更に、本実施形態では、簡易セルの作製方
法や大きさについて説明したが、本発明はこれらに限定
されるものではなく、上述した特許請求の範囲において
種々の態様を採ることができる。
Further, in the present embodiment, the method of manufacturing and the size of the simple cell have been described, but the present invention is not limited to these, and various aspects can be adopted in the above-described claims. .

【0036】[0036]

【発明の効果】以上説明したように、本発明によれば、
異種金属がセパレータ上に黒点として強制的に析出され
るので、セパレータ上の黒点を目視することにより、正
極活物質合剤中に異種金属が混入されているかの有無を
簡易かつ明確に判別することができる、という効果を得
ることができる。
As described above, according to the present invention,
Since foreign metals are forcibly precipitated as black spots on the separator, it is easy to clearly and clearly determine whether or not foreign metals are mixed in the positive electrode active material mixture by visually observing the black spots on the separator. Can be obtained.

【図面の簡単な説明】[Brief description of the drawings]

【図1】本発明が適用可能な実施形態の正極活物質合剤
の検査方法に従って作製した正極板及び負極板であり、
(A)は正極板の平面図、(B)は負極板の平面図であ
る。
FIG. 1 shows a positive electrode plate and a negative electrode plate manufactured according to a method for testing a positive electrode active material mixture according to an embodiment to which the present invention can be applied;
(A) is a plan view of a positive electrode plate, and (B) is a plan view of a negative electrode plate.

【図2】実施形態の検査方法に従って作製した簡易セル
の外観斜視図である。
FIG. 2 is an external perspective view of a simple cell manufactured according to the inspection method of the embodiment.

【符号の説明】[Explanation of symbols]

1 正極板 2 負極板 3 セパレータ 4 容器 5 Oリング 6、7 ネジ 11 正極集電リード片 21 負極集電リード片 41 上蓋 42 下蓋 DESCRIPTION OF SYMBOLS 1 Positive electrode plate 2 Negative electrode plate 3 Separator 4 Container 5 O-ring 6, 7 screw 11 Positive current collecting lead piece 21 Negative current collecting lead piece 41 Upper lid 42 Lower lid

───────────────────────────────────────────────────── フロントページの続き (72)発明者 井口 智博 東京都中央区日本橋本町二丁目8番7号 新神戸電機株式会社内 (72)発明者 弘中 健介 東京都中央区日本橋本町二丁目8番7号 新神戸電機株式会社内 Fターム(参考) 5H029 AJ14 AK03 AL06 AM03 AM05 AM07 5H050 AA19 BA05 BA17 CA08 CA09 CB07 GA28  ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tomohiro Iguchi 2-8-7 Nihonbashi Honcho, Chuo-ku, Tokyo Inside Shin-Kobe Electric Machinery Co., Ltd. (72) Kensuke Hironaka 2-87 Nihonbashi Honcho, Chuo-ku, Tokyo F-term in Shin-Kobe Electric Co., Ltd. (reference) 5H029 AJ14 AK03 AL06 AM03 AM05 AM07 5H050 AA19 BA05 BA17 CA08 CA09 CB07 GA28

Claims (2)

【特許請求の範囲】[Claims] 【請求項1】 リチウムイオンを吸蔵・放出可能な正極
活物質とこの正極活物質を結着させる結着剤とを含有す
る正極活物質合剤中の異種金属の有無を判別する正極活
物質合剤の検査方法であって、前記正極活物質合剤を塗
布した正極と、負極と、をセパレータを介して対向させ
て電解液中に浸潤させ、前記正極及び負極間に所定電圧
を印加して前記正極活物質合剤中の異種金属を前記セパ
レータ上に黒点として強制的に析出させることを特徴と
する正極活物質合剤の検査方法。
1. A positive electrode active material mixture comprising: a positive electrode active material mixture containing a positive electrode active material capable of occluding and releasing lithium ions and a binder for binding the positive electrode active material; A method for testing an agent, in which the positive electrode coated with the positive electrode active material mixture and the negative electrode are opposed to each other via a separator, soaked in an electrolytic solution, and a predetermined voltage is applied between the positive electrode and the negative electrode. A method for testing a positive electrode active material mixture, comprising forcibly precipitating a dissimilar metal in the positive electrode active material mixture as a black spot on the separator.
【請求項2】 前記析出した黒点を元素分析する工程を
更に含むことを特徴とする請求項1記載の正極活物質合
剤の検査方法。
2. The method for testing a positive electrode active material mixture according to claim 1, further comprising an elemental analysis step of the deposited black spots.
JP2000164188A 2000-06-01 2000-06-01 Method of testing active material mixture for positive electrode Abandoned JP2001345094A (en)

Priority Applications (1)

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Publication Number Publication Date
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Family

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Country Link
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008192495A (en) * 2007-02-06 2008-08-21 Matsushita Electric Ind Co Ltd Internal short circuit evaluation method and internal short circuit evaluation device for battery as well as battery, battery pack and their manufacturing method
JP2013058348A (en) * 2011-09-07 2013-03-28 Sanoh Industrial Co Ltd Secondary battery evaluation jig and secondary battery evaluation method
CN112986837A (en) * 2021-05-19 2021-06-18 昆山聚创新能源科技有限公司 Method for calculating dissolving and separating-out speed of metal impurities in lithium ion battery

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008192495A (en) * 2007-02-06 2008-08-21 Matsushita Electric Ind Co Ltd Internal short circuit evaluation method and internal short circuit evaluation device for battery as well as battery, battery pack and their manufacturing method
JP2013058348A (en) * 2011-09-07 2013-03-28 Sanoh Industrial Co Ltd Secondary battery evaluation jig and secondary battery evaluation method
CN112986837A (en) * 2021-05-19 2021-06-18 昆山聚创新能源科技有限公司 Method for calculating dissolving and separating-out speed of metal impurities in lithium ion battery
CN112986837B (en) * 2021-05-19 2021-08-06 昆山聚创新能源科技有限公司 Method for calculating dissolving and separating-out speed of metal impurities in lithium ion battery

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