JP2020149881A - Secondary battery - Google Patents

Secondary battery Download PDF

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JP2020149881A
JP2020149881A JP2019046949A JP2019046949A JP2020149881A JP 2020149881 A JP2020149881 A JP 2020149881A JP 2019046949 A JP2019046949 A JP 2019046949A JP 2019046949 A JP2019046949 A JP 2019046949A JP 2020149881 A JP2020149881 A JP 2020149881A
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positive electrode
negative electrode
lead
insulating tape
base material
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JP7320166B2 (en
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正嗣 青谷
Masatsugu Aotani
正嗣 青谷
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Sanyo Electric Co Ltd
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Sanyo Electric Co Ltd
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    • Y—GENERAL 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Abstract

To provide a secondary battery in which the occurrence of an internal short circuit can be prevented even when the secondary battery is subject to a strong impact force deforming the secondary battery from the outside.SOLUTION: The secondary battery which is an example of an embodiment comprises an electrode body in which a positive electrode and a negative electrode are wound around a separator. At least one of the positive electrode and the negative electrode comprises a lead connected to an exposed portion where the surface of a core body is exposed and an insulating tape covering the lead and the exposed portion. The insulating tape includes a base material and an adhesive layer provided on one surface of the base material. On one surface of the base material of the insulating tape, the adhesive layers are provided on both sides in the width direction of the base material, and in the central portion in the width direction of the base material that overlaps with the lead, a region where the adhesive layer does not exist is wider than the width of the lead is formed.SELECTED DRAWING: Figure 4

Description

本開示は、二次電池に関し、より詳しくは電極に貼着された絶縁テープを備える二次電池に関する。 The present disclosure relates to a secondary battery, and more particularly to a secondary battery including an insulating tape attached to an electrode.

従来、巻回型の電極体を備えた二次電池において、電極体を構成する電極に芯体表面が露出した露出部を設け、集電用のリードを当該露出部に接続した構造が知られている。リード及び露出部の表面は、合剤層が存在しない、低抵抗な金属の表面が露出した部分であるため、ここで内部短絡が発生すると、短絡箇所に大電流が流れて電池の発熱量が多くなる。そのため、リード及び露出部を覆うように絶縁テープを貼着し、かかる低抵抗な短絡の発生を防止している（例えば、特許文献１参照）。 Conventionally, in a secondary battery provided with a winding type electrode body, a structure is known in which an exposed portion whose core body surface is exposed is provided on an electrode constituting the electrode body, and a lead for current collection is connected to the exposed portion. ing. Since the surfaces of the leads and exposed parts are exposed parts of low resistance metal without a mixture layer, if an internal short circuit occurs here, a large current will flow to the shorted part and the amount of heat generated by the battery will increase. More. Therefore, an insulating tape is attached so as to cover the lead and the exposed portion to prevent the occurrence of such a low resistance short circuit (see, for example, Patent Document 1).

特開２００８−２３４８５５号公報Japanese Unexamined Patent Publication No. 2008-234855

ところで、二次電池では、電池が変形するような強い衝撃力が外部から加わった場合でも、発火を起こすような内部短絡を生じさせない高い安全性能が求められている。上記のように、リード及び露出部を覆う絶縁テープは低抵抗な短絡の発生を防止するが、リード及び絶縁テープはある程度の厚みを有するため、これらの厚みに起因して電極表面に段差が形成される。そして、電池が変形するような強い衝撃力が外部から加わったときに、段差が存在する部分でセパレータが破断して短絡が発生する場合がある。 By the way, a secondary battery is required to have high safety performance that does not cause an internal short circuit that causes ignition even when a strong impact force that deforms the battery is applied from the outside. As described above, the insulating tape covering the lead and the exposed portion prevents the occurrence of a low-resistance short circuit, but since the lead and the insulating tape have a certain thickness, a step is formed on the electrode surface due to these thicknesses. Will be done. Then, when a strong impact force that deforms the battery is applied from the outside, the separator may break at the portion where the step exists and a short circuit may occur.

本開示の目的は、電池が変形するような強い衝撃力が外部から加わった場合においても、内部短絡の発生を防止できる二次電池を提供することである。 An object of the present disclosure is to provide a secondary battery capable of preventing the occurrence of an internal short circuit even when a strong impact force that deforms the battery is applied from the outside.

本開示の一態様である二次電池は、正極と負極がセパレータを介して巻回された電極体を備える二次電池において、前記正極及び前記負極は、芯体と、前記芯体の表面に設けられた合剤層とを含み、前記正極及び前記負極の少なくとも一方には、前記芯体の表面が露出した露出部に接続されるリードと、前記リード及び前記露出部を覆う絶縁テープとが設けられる。前記絶縁テープは、基材と、前記基材の一方の面に設けられた接着層とを含み、前記基材の一方の面において、前記接着層は前記基材の幅方向両側に設けられ、前記リードと重なる前記基材の幅方向中央部には、前記接着層が存在しない領域が前記リードの幅以上の幅で形成されている。 The secondary battery according to one aspect of the present disclosure is a secondary battery including an electrode body in which a positive electrode and a negative electrode are wound around a separator, and the positive electrode and the negative electrode are formed on a core body and a surface of the core body. A lead connected to an exposed portion where the surface of the core body is exposed, and an insulating tape covering the lead and the exposed portion are provided on at least one of the positive electrode and the negative electrode, including the provided mixture layer. It is provided. The insulating tape includes a base material and an adhesive layer provided on one surface of the base material, and the adhesive layer is provided on both sides in the width direction of the base material on one surface of the base material. A region in which the adhesive layer does not exist is formed at a width equal to or greater than the width of the lead in the central portion of the base material that overlaps with the lead in the width direction.

本開示の一態様である二次電池によれば、電池が変形するような強い衝撃力が外部から加わった場合においても、内部短絡の発生を防止できる。 According to the secondary battery which is one aspect of the present disclosure, it is possible to prevent the occurrence of an internal short circuit even when a strong impact force that deforms the battery is applied from the outside.

実施形態の一例である非水電解質二次電池の断面図である。It is sectional drawing of the non-aqueous electrolyte secondary battery which is an example of Embodiment. 実施形態の一例である正極の一部を示す図である。It is a figure which shows a part of the positive electrode which is an example of an embodiment. 実施形態の一例である絶縁テープを示す図である。It is a figure which shows the insulating tape which is an example of an embodiment. 図２中のＡＡ線断面の一部を示す図である。It is a figure which shows a part of the cross section of AA line in FIG.

上述のように、二次電池において内部短絡の発生を防止することは重要な課題である。本発明者は、リードと重なるテープの幅方向中央部に接着層が存在しない領域（リードの幅≦当該領域の幅）を形成した絶縁テープを用いることで、電池が変形するような強い衝撃力が外部から加わった場合においても、内部短絡の発生が高度に抑制されることを見出した。この絶縁テープはリードと重なる部分の厚みが薄くなっているため、リード及び絶縁テープの厚みに起因して正極の表面に形成される段差を小さくすることができる。この絶縁テープを用いることで段差の影響を緩和され、段差が形成された部分でセパレータが破断して短絡が生じることが防止されると考えられる。 As described above, it is an important issue to prevent the occurrence of an internal short circuit in the secondary battery. The present inventor uses an insulating tape in which a region (lead width ≤ width of the region) where an adhesive layer does not exist is formed in the central portion of the tape overlapping the lead in the width direction, so that a strong impact force that deforms the battery is obtained. It was found that the occurrence of internal short circuit is highly suppressed even when is applied from the outside. Since the thickness of the portion of the insulating tape that overlaps with the lead is thin, the step formed on the surface of the positive electrode due to the thickness of the lead and the insulating tape can be reduced. It is considered that the use of this insulating tape alleviates the influence of the step and prevents the separator from breaking at the portion where the step is formed to cause a short circuit.

以下、本開示の実施形態の一例について詳細に説明する。実施形態の説明で参照する図面は模式的に記載されたものであるから、各構成要素の寸法比率等は以下の説明を参酌して判断されるべきである。 Hereinafter, an example of the embodiment of the present disclosure will be described in detail. Since the drawings referred to in the description of the embodiment are schematically described, the dimensional ratio and the like of each component should be determined in consideration of the following description.

本実施形態では、巻回型の電極体が有底円筒形状の外装缶に収容された二次電池を例示するが、外装体は円筒形の外装缶に限定されず、例えば角形の外装缶であってもよく、金属層及び樹脂層を含むラミネートシートで構成された外装体であってもよい。また、電極体の外周面に形成される負極の芯体露出部が外装缶の内面に接触して負極と外装缶が電気的に接続された構造を例示するが、電極体の外周面と外装缶の内面は電気的に接続されていなくてもよい。 In the present embodiment, a secondary battery in which a wound electrode body is housed in a bottomed cylindrical outer can is illustrated, but the outer body is not limited to the cylindrical outer can, for example, a square outer can. It may be an exterior body made of a laminated sheet including a metal layer and a resin layer. Further, the structure in which the exposed portion of the core body of the negative electrode formed on the outer peripheral surface of the electrode body is in contact with the inner surface of the outer can and the negative electrode and the outer can are electrically connected is illustrated. The inner surface of the can does not have to be electrically connected.

図１は、実施形態の一例である二次電池１０の断面図である。図１に例示するように、二次電池１０は、電極体１４と、電解質（図示せず）と、電極体１４及び電解質を収容する外装缶１６とを備える。電極体１４は、正極１１、負極１２、及びセパレータ１３を有し、正極１１と負極１２がセパレータ１３を介して渦巻き状に巻回された巻回構造を有する。外装缶１６は、軸方向一方側が開口した有底円筒形状の金属製容器であって、外装缶１６の開口は封口体１７によって塞がれている。以下では、説明の便宜上、二次電池１０の封口体１７側を上、外装缶１６の底部側を下とする。 FIG. 1 is a cross-sectional view of the secondary battery 10 which is an example of the embodiment. As illustrated in FIG. 1, the secondary battery 10 includes an electrode body 14, an electrolyte (not shown), and an outer can 16 containing the electrode body 14 and the electrolyte. The electrode body 14 has a positive electrode 11, a negative electrode 12, and a separator 13, and has a wound structure in which the positive electrode 11 and the negative electrode 12 are spirally wound via the separator 13. The outer can 16 is a bottomed cylindrical metal container having an opening on one side in the axial direction, and the opening of the outer can 16 is closed by a sealing body 17. In the following, for convenience of explanation, the sealing body 17 side of the secondary battery 10 is on the top, and the bottom side of the outer can 16 is on the bottom.

電解質には、例えば非水電解質が用いられる。非水電解質は、非水溶媒と、非水溶媒に溶解した電解質塩とを含む。非水溶媒には、例えばエステル類、エーテル類、ニトリル類、アミド類、及びこれらの２種以上の混合溶媒等を用いてもよい。非水溶媒は、これら溶媒の水素の少なくとも一部をフッ素等のハロゲン原子で置換したハロゲン置換体を含有していてもよい。なお、非水電解質は液体電解質に限定されず、固体電解質であってもよい。電解質塩には、例えばＬｉＰＦ６等のリチウム塩が使用される。電解質の種類は特に限定されず、水系電解質であってもよい。 As the electrolyte, for example, a non-aqueous electrolyte is used. The non-aqueous electrolyte contains a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. As the non-aqueous solvent, for example, esters, ethers, nitriles, amides, and a mixed solvent of two or more of these may be used. The non-aqueous solvent may contain a halogen substituent in which at least a part of hydrogen in these solvents is replaced with a halogen atom such as fluorine. The non-aqueous electrolyte is not limited to the liquid electrolyte, and may be a solid electrolyte. As the electrolyte salt, for example, a lithium salt such as LiPF 6 is used. The type of the electrolyte is not particularly limited, and may be an aqueous electrolyte.

電極体１４を構成する正極１１、負極１２、及びセパレータ１３は、いずれも帯状の長尺体であって、渦巻状に巻回されることで電極体１４の径方向に交互に積層される。正極１１は、正極芯体３０と、正極芯体３０の表面に設けられた正極合剤層３１とを有する。同様に、負極１２は、負極芯体４０と、負極芯体４０の表面に設けられた負極合剤層４１とを有する。二次電池１０は、電極体１４の上下にそれぞれ配置された絶縁板１８，１９を備える。 The positive electrode 11, the negative electrode 12, and the separator 13 constituting the electrode body 14 are all strip-shaped long bodies, and are alternately laminated in the radial direction of the electrode body 14 by being wound in a spiral shape. The positive electrode 11 has a positive electrode core body 30 and a positive electrode mixture layer 31 provided on the surface of the positive electrode core body 30. Similarly, the negative electrode 12 has a negative electrode core body 40 and a negative electrode mixture layer 41 provided on the surface of the negative electrode core body 40. The secondary battery 10 includes insulating plates 18 and 19 arranged above and below the electrode body 14, respectively.

電極体１４の外周面には、負極１２が配置され、負極芯体４０の表面が露出した露出部４２が形成されている。露出部４２は、電極体１４の外周面の一部に形成されてもよいが、好ましくは外周面の全域に形成される。露出部４２は、電極体１４の外側を向いた負極芯体４０の片面（外面）のみに形成されてもよく、負極芯体４０の両面に形成されてもよい。露出部４２は、例えば電極体１４の外周面に位置する負極芯体４０の長手方向一端から電極体１４の周長の１周〜２周分程度の長さの範囲に形成される。 A negative electrode 12 is arranged on the outer peripheral surface of the electrode body 14, and an exposed portion 42 in which the surface of the negative electrode core body 40 is exposed is formed. The exposed portion 42 may be formed on a part of the outer peripheral surface of the electrode body 14, but is preferably formed on the entire outer peripheral surface. The exposed portion 42 may be formed only on one side (outer surface) of the negative electrode core 40 facing the outside of the electrode body 14, or may be formed on both sides of the negative electrode core 40. The exposed portion 42 is formed, for example, in a range of about one to two circumferences of the peripheral length of the electrode body 14 from one end in the longitudinal direction of the negative electrode core body 40 located on the outer peripheral surface of the electrode body 14.

二次電池１０では、負極１２の露出部４２が外装缶１６の内面に接触して、負極１２と外装缶１６が電気的に接続されている。本実施形態では、封口体１７が正極外部端子となり、外装缶１６が負極外部端子となる。正極１１に取り付けられた正極リード２０は、絶縁板１８の貫通孔を通って封口体１７側に延び、封口体１７の底板である内部端子板２３の下面に溶接等で接続される。負極１２には、負極リードが接続されていなくてもよく、電極体１４の巻芯側に位置する負極１２の長手方向他端部に露出部を形成し、外装缶１６の底部内面に溶接等で接続される負極リードが当該露出部に取り付けられていてもよい。 In the secondary battery 10, the exposed portion 42 of the negative electrode 12 comes into contact with the inner surface of the outer can 16, and the negative electrode 12 and the outer can 16 are electrically connected. In the present embodiment, the sealing body 17 serves as the positive electrode external terminal, and the outer can 16 serves as the negative electrode external terminal. The positive electrode lead 20 attached to the positive electrode 11 extends to the sealing body 17 side through the through hole of the insulating plate 18, and is connected to the lower surface of the internal terminal plate 23 which is the bottom plate of the sealing body 17 by welding or the like. The negative electrode lead does not have to be connected to the negative electrode 12, and an exposed portion is formed at the other end in the longitudinal direction of the negative electrode 12 located on the winding core side of the electrode body 14, and is welded to the inner surface of the bottom of the outer can 16. The negative electrode lead connected by is may be attached to the exposed portion.

外装缶１６と封口体１７の間にはガスケット２８が設けられ、電池内部の密閉性が確保される。外装缶１６には、側面部の一部が内側に張り出した、封口体１７を支持する溝入部２１が形成されている。溝入部２１は、外装缶１６の周方向に沿って環状に形成されることが好ましく、その上面で封口体１７を支持する。封口体１７は、溝入部２１と、封口体１７に対して加締められた外装缶１６の開口端部とにより、外装缶１６の上部に固定される。 A gasket 28 is provided between the outer can 16 and the sealing body 17 to ensure the airtightness inside the battery. The outer can 16 is formed with a grooved portion 21 that supports the sealing body 17, with a part of the side surface portion protruding inward. The grooved portion 21 is preferably formed in an annular shape along the circumferential direction of the outer can 16, and the sealing body 17 is supported on the upper surface thereof. The sealing body 17 is fixed to the upper part of the outer can 16 by the grooved portion 21 and the open end portion of the outer can 16 crimped to the sealing body 17.

封口体１７は、電極体１４側から順に、内部端子板２３、下弁体２４、絶縁部材２５、上弁体２６、及びキャップ２７が積層された構造を有する。封口体１７を構成する各部材は、例えば円盤状又はリング状を呈し、絶縁部材２５を除く各部材は互いに電気的に接続されている。下弁体２４と上弁体２６は各々の中央部で互いに接続され、各々の周縁部の間には絶縁部材２５が介在している。異常発熱で電池の内圧が上昇すると、下弁体２４が上弁体２６をキャップ２７側に押し上げるように変形して破断し、下弁体２４と上弁体２６の間の電流経路が遮断される。更に内圧が上昇すると、上弁体２６が破断し、キャップ２７の通気孔からガスが排出される。 The sealing body 17 has a structure in which an internal terminal plate 23, a lower valve body 24, an insulating member 25, an upper valve body 26, and a cap 27 are laminated in this order from the electrode body 14 side. Each member constituting the sealing body 17 has, for example, a disk shape or a ring shape, and each member except the insulating member 25 is electrically connected to each other. The lower valve body 24 and the upper valve body 26 are connected to each other at the central portion thereof, and an insulating member 25 is interposed between the peripheral portions thereof. When the internal pressure of the battery rises due to abnormal heat generation, the lower valve body 24 deforms and breaks so as to push the upper valve body 26 toward the cap 27 side, and the current path between the lower valve body 24 and the upper valve body 26 is cut off. To. When the internal pressure further rises, the upper valve body 26 breaks and gas is discharged from the ventilation holes of the cap 27.

以下、図２〜図４を更に参照しながら、電極体１４を構成する正極１１、負極１２、及びセパレータ１３について、特に正極１１及び正極１１に貼着される絶縁テープ５０について詳説する。図２は正極１１の正面図、図４は図２中のＡＡ線断面の一部を示す図である。図３は、絶縁テープ５０の平面図及び背面図である。 Hereinafter, with reference to FIGS. 2 to 4, the positive electrode 11, the negative electrode 12, and the separator 13 constituting the electrode body 14 will be described in detail, and in particular, the insulating tape 50 attached to the positive electrode 11 and the positive electrode 11 will be described in detail. FIG. 2 is a front view of the positive electrode 11, and FIG. 4 is a view showing a part of the AA line cross section in FIG. FIG. 3 is a plan view and a rear view of the insulating tape 50.

［正極］
正極１１は、上述の通り、正極芯体３０と、正極芯体３０の表面に設けられた正極合剤層３１とを有する。正極芯体３０には、アルミニウムなど正極１１の電位範囲で安定な金属の箔、当該金属を表層に配置したフィルム等を用いることができる。正極合剤層３１は、正極活物質、導電剤、及び結着剤を含み、正極リード２０が接続される部分である露出部３２を除く正極芯体３０の両面に設けられることが好ましい。正極合剤層３１の厚みは、正極芯体３０の片側で、例えば５０μｍ〜１５０μｍである。正極１１は、例えば正極芯体３０の表面に正極活物質、導電剤、及び結着剤等を含む正極合剤スラリーを塗布し、塗膜を乾燥させた後、圧縮して正極合剤層３１を正極芯体３０の両面に形成することにより作製できる。 [Positive electrode]
As described above, the positive electrode 11 has a positive electrode core body 30 and a positive electrode mixture layer 31 provided on the surface of the positive electrode core body 30. For the positive electrode core body 30, a foil of a metal such as aluminum that is stable in the potential range of the positive electrode 11, a film in which the metal is arranged on the surface layer, or the like can be used. The positive electrode mixture layer 31 contains a positive electrode active material, a conductive agent, and a binder, and is preferably provided on both sides of the positive electrode core body 30 excluding the exposed portion 32 where the positive electrode lead 20 is connected. The thickness of the positive electrode mixture layer 31 is, for example, 50 μm to 150 μm on one side of the positive electrode core body 30. For the positive electrode 11, for example, a positive electrode mixture slurry containing a positive electrode active material, a conductive agent, a binder, and the like is applied to the surface of the positive electrode core 30, the coating film is dried, and then compressed to compress the positive electrode mixture layer 31. Can be produced by forming on both sides of the positive electrode core body 30.

正極活物質は、リチウム含有遷移金属複合酸化物を主成分として構成される。リチウム含有遷移金属複合酸化物に含有される金属元素としては、Ｎｉ、Ｃｏ、Ｍｎ、Ａｌ、Ｂ、Ｍｇ、Ｔｉ、Ｖ、Ｃｒ、Ｆｅ、Ｃｕ、Ｚｎ、Ｇａ、Ｓｒ、Ｚｒ、Ｎｂ、Ｉｎ、Ｓｎ、Ｔａ、Ｗ等が挙げられる。好適なリチウム含有遷移金属複合酸化物の一例は、Ｎｉ、Ｃｏ、Ｍｎの少なくとも１種を含有する複合酸化物である。具体例としては、Ｎｉ、Ｃｏ、Ｍｎを含有するリチウム含有遷移金属複合酸化物、Ｎｉ、Ｃｏ、Ａｌを含有するリチウム含有遷移金属複合酸化物が挙げられる。 The positive electrode active material is composed mainly of a lithium-containing transition metal composite oxide. Examples of the metal elements contained in the lithium-containing transition metal composite oxide include Ni, Co, Mn, Al, B, Mg, Ti, V, Cr, Fe, Cu, Zn, Ga, Sr, Zr, Nb, In, Sn, Ta, W and the like can be mentioned. An example of a suitable lithium-containing transition metal composite oxide is a composite oxide containing at least one of Ni, Co, and Mn. Specific examples include a lithium-containing transition metal composite oxide containing Ni, Co and Mn, and a lithium-containing transition metal composite oxide containing Ni, Co and Al.

正極合剤層３１に含まれる導電剤としては、カーボンブラック、アセチレンブラック、ケッチェンブラック、黒鉛等の炭素材料が例示できる。正極合剤層３１に含まれる結着剤としては、ポリテトラフルオロエチレン（ＰＴＦＥ）、ポリフッ化ビニリデン（ＰＶｄＦ）等のフッ素樹脂、ポリアクリロニトリル（ＰＡＮ）、ポリイミド樹脂、アクリル樹脂、ポリオレフィン樹脂などが例示できる。これらの樹脂と、カルボキシメチルセルロース（ＣＭＣ）又はその塩等のセルロース誘導体、ポリエチレンオキシド（ＰＥＯ）等が併用されてもよい。 Examples of the conductive agent contained in the positive electrode mixture layer 31 include carbon materials such as carbon black, acetylene black, ketjen black, and graphite. Examples of the binder contained in the positive electrode mixture layer 31 include fluororesins such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), polyimide resins, acrylic resins, and polyolefin resins. it can. These resins may be used in combination with cellulose derivatives such as carboxymethyl cellulose (CMC) or salts thereof, polyethylene oxide (PEO) and the like.

図２に例示するように、正極１１には、正極芯体３０の表面が露出した露出部３２に接続される正極リード２０と、正極リード２０及び露出部３２を覆う絶縁テープ５０とが設けられている。露出部３２は、正極芯体３０の表面が正極合剤層３１に覆われずに露出した部分であって、正極１１の厚み方向に重なって正極１１の両面にそれぞれ形成される。本実施形態では、正極１１の長手方向中央部に露出部３２が形成されており、正極リード２０及び絶縁テープ５０が正極１１の長手方向中央部に配置されている。また、露出部３２は、正極１１の短手方向全長にわたって、正極リード２０の幅Ｗよりも広い幅で形成されている。露出部３２は、正極１１の短手方向に長い正面視長方形状を有する。 As illustrated in FIG. 2, the positive electrode 11 is provided with a positive electrode lead 20 connected to an exposed portion 32 on which the surface of the positive electrode core 30 is exposed, and an insulating tape 50 covering the positive electrode lead 20 and the exposed portion 32. ing. The exposed portion 32 is a portion where the surface of the positive electrode core 30 is exposed without being covered by the positive electrode mixture layer 31, and is formed on both sides of the positive electrode 11 so as to overlap in the thickness direction of the positive electrode 11. In the present embodiment, the exposed portion 32 is formed in the central portion in the longitudinal direction of the positive electrode 11, and the positive electrode lead 20 and the insulating tape 50 are arranged in the central portion in the longitudinal direction of the positive electrode 11. Further, the exposed portion 32 is formed to have a width wider than the width W of the positive electrode lead 20 over the entire length of the positive electrode 11 in the lateral direction. The exposed portion 32 has a rectangular shape in front view that is long in the lateral direction of the positive electrode 11.

正極リード２０は、一般的に、正極芯体３０及び正極合剤層３１よりも厚みのある帯状の導電部材である。正極リード２０は、例えば５０μｍ〜５００μｍの厚みと、３ｍｍ〜４ｍｍの幅Ｗを有する。正極リード２０の構成材料は特に限定されないが、好ましくはアルミニウムを主成分とする金属で構成される。正極リード２０は、正極１１の両面に形成された２つの露出部３２のうちの一方に溶接等により接続される。正極リード２０の一部は、正極芯体３０の上端から延出して、封口体１７の内部端子板２３に接続される。 The positive electrode lead 20 is generally a strip-shaped conductive member thicker than the positive electrode core 30 and the positive electrode mixture layer 31. The positive electrode lead 20 has, for example, a thickness of 50 μm to 500 μm and a width W of 3 mm to 4 mm. The constituent material of the positive electrode lead 20 is not particularly limited, but is preferably composed of a metal containing aluminum as a main component. The positive electrode lead 20 is connected to one of the two exposed portions 32 formed on both sides of the positive electrode 11 by welding or the like. A part of the positive electrode lead 20 extends from the upper end of the positive electrode core body 30 and is connected to the internal terminal plate 23 of the sealing body 17.

絶縁テープ５０は、正極リード２０が取り付けられる正極１１の一方の面（以下、「第１面」とする）に加えて、正極１１の他方の面（以下、「第２面」とする）にも露出部３２を覆うように貼着されることが好ましい。即ち、正極１１に形成された２つの露出部３２は、いずれも絶縁テープ５０によって覆われる。２枚の絶縁テープ５０は互いに接合されていてもよい。なお、正極１１の第２面に貼着される絶縁テープには、従来公知のテープを用いてもよい。 The insulating tape 50 is provided on one surface of the positive electrode 11 (hereinafter, referred to as “first surface”) to which the positive electrode lead 20 is attached, and on the other surface of the positive electrode 11 (hereinafter, referred to as “second surface”). Is also preferably attached so as to cover the exposed portion 32. That is, the two exposed portions 32 formed on the positive electrode 11 are both covered with the insulating tape 50. The two insulating tapes 50 may be bonded to each other. A conventionally known tape may be used as the insulating tape to be attached to the second surface of the positive electrode 11.

絶縁テープ５０は、正極リード２０及び露出部３２よりも幅広の正面視長方形状（短冊状）を有する。絶縁テープ５０は、正極リード２０のうち、露出部３２上に位置する部分の全体を覆った状態で、正極１１の第１面に貼着されることが好ましい。また、絶縁テープ５０は、例えば、２つの露出部３２の全体を覆って正極１１の第１面及び第２面にそれぞれ貼着される。絶縁テープ５０は、その長手方向が正極１１の短手方向に沿うように、幅方向が正極１１の長手方向に沿うように貼着される。 The insulating tape 50 has a rectangular shape (strip shape) in front view that is wider than the positive electrode lead 20 and the exposed portion 32. The insulating tape 50 is preferably attached to the first surface of the positive electrode 11 in a state of covering the entire portion of the positive electrode lead 20 located on the exposed portion 32. Further, for example, the insulating tape 50 covers the entire two exposed portions 32 and is attached to the first surface and the second surface of the positive electrode 11, respectively. The insulating tape 50 is attached so that its longitudinal direction is along the lateral direction of the positive electrode 11 and its width direction is along the longitudinal direction of the positive electrode 11.

絶縁テープ５０は、正極リード２０の正極芯体３０の上端から延出した延出部にわたって貼着されることが好ましい。正極リード２０の延出部の一部はセパレータ１３を介して負極１２と対向するため、セパレータ１３が損傷したときに低抵抗な短絡の発生が懸念される。ゆえに、当該部分にも絶縁テープ５０が貼着される。また、絶縁テープ５０は、露出部３２の全体を確実に覆うことができるように、露出部３２よりも大きな寸法を有し、露出部３２の両側に形成される正極合剤層３１の一部を覆うと共に、正極１１の短手方向両側にはみ出した状態で貼着される。 The insulating tape 50 is preferably attached over an extending portion extending from the upper end of the positive electrode core body 30 of the positive electrode lead 20. Since a part of the extending portion of the positive electrode lead 20 faces the negative electrode 12 via the separator 13, there is a concern that a low resistance short circuit may occur when the separator 13 is damaged. Therefore, the insulating tape 50 is also attached to the portion. Further, the insulating tape 50 has a size larger than that of the exposed portion 32 so that the entire exposed portion 32 can be reliably covered, and is a part of the positive electrode mixture layer 31 formed on both sides of the exposed portion 32. Is attached to both sides of the positive electrode 11 in the lateral direction while covering the above.

図３及び図４に例示するように、絶縁テープ５０は、基材５１と、基材５１の一方の面（以下、「裏面」とする）に設けられた接着層５２とを有する。絶縁テープ５０の厚みは特に限定されないが、一例としては２０μｍ〜７０μｍである。基材５１の厚みは、一般的に接着層５２よりも厚く、例えば１０μｍ〜４５μｍである。接着層５２の厚みは、例えば５μｍ〜３０μｍである。基材５１には、本開示の目的を損なわない範囲で接着層５２以外の層が設けられていてもよい。 As illustrated in FIGS. 3 and 4, the insulating tape 50 has a base material 51 and an adhesive layer 52 provided on one surface (hereinafter, referred to as “back surface”) of the base material 51. The thickness of the insulating tape 50 is not particularly limited, but is, for example, 20 μm to 70 μm. The thickness of the base material 51 is generally thicker than that of the adhesive layer 52, for example, 10 μm to 45 μm. The thickness of the adhesive layer 52 is, for example, 5 μm to 30 μm. The base material 51 may be provided with a layer other than the adhesive layer 52 as long as the object of the present disclosure is not impaired.

基材５１は、絶縁性、耐電解液性等を有する樹脂を主成分として構成される。基材５１を構成する好適な樹脂としては、ポリエチレンテレフタレート（ＰＥＴ）等のポリエステル、ポリプロピレン（ＰＰ）等のポリオレフィン、ポリイミド（ＰＩ）、ポリフェニレンサルファイド、ポリアミド、ポリアミドイミドなどが例示できる。中でも、機械的強度（突き刺し強度）が高いポリイミドが特に好ましい。基材５１には、例えばポリイミドで構成される樹脂フィルムを用いることができる。基材５１は、アルミナ、チタニア等のフィラーを含んでいてもよい。 The base material 51 is composed mainly of a resin having insulating properties, electrolytic solution resistance, and the like. Examples of suitable resins constituting the base material 51 include polyesters such as polyethylene terephthalate (PET), polyolefins such as polypropylene (PP), polyimide (PI), polyphenylene sulfide, polyamides, and polyamideimides. Of these, polyimide having high mechanical strength (piercing strength) is particularly preferable. For the base material 51, for example, a resin film made of polyimide can be used. The base material 51 may contain a filler such as alumina or titania.

接着層５２は、正極１１に対する接着性をテープに付与するための層である。接着層５２は、例えば基材５１の裏面に接着剤を塗工して形成される。接着層５２は、絶縁性、耐電解液性等に優れた接着剤を用いて構成されることが好ましい。接着層５２を構成する接着剤は、ホットメルト型又は熱硬化型であってもよいが、生産性等の観点から、室温で粘着性を有するものが好ましい。接着層５２を構成する接着剤の一例は、アクリル系接着剤、合成ゴム系接着剤である。 The adhesive layer 52 is a layer for imparting adhesiveness to the positive electrode 11 to the tape. The adhesive layer 52 is formed, for example, by applying an adhesive to the back surface of the base material 51. The adhesive layer 52 is preferably formed by using an adhesive having excellent insulating properties, electrolytic solution resistance, and the like. The adhesive constituting the adhesive layer 52 may be a hot melt type or a thermosetting type, but from the viewpoint of productivity and the like, an adhesive having adhesiveness at room temperature is preferable. Examples of the adhesive constituting the adhesive layer 52 are an acrylic adhesive and a synthetic rubber adhesive.

絶縁テープ５０は、接着層５２によって、露出部３２の両側に形成された正極合剤層３１の表面に貼着される。基材５１の裏面において、接着層５２は基材５１の幅方向両側に設けられ、正極リード２０と重なる基材５１の幅方向中央部には接着層５２が存在しない領域５３が正極リード２０の幅Ｗ以上の幅Ｗ２で形成されている。絶縁テープ５０は、領域５３が正極リード２０と重なり、正極リード２０の表面に当接した状態で正極１１の第１面に貼着される。即ち、絶縁テープ５０は正極リード２０に貼着されない。なお、絶縁テープ５０は露出部３２に貼着されていてもよい。 The insulating tape 50 is attached to the surface of the positive electrode mixture layer 31 formed on both sides of the exposed portion 32 by the adhesive layer 52. On the back surface of the base material 51, the adhesive layers 52 are provided on both sides in the width direction of the base material 51, and the region 53 in which the adhesive layer 52 does not exist in the central portion in the width direction of the base material 51 overlapping the positive electrode lead 20 is the positive electrode lead 20. It is formed with a width W2 equal to or larger than the width W. The insulating tape 50 is attached to the first surface of the positive electrode 11 in a state where the region 53 overlaps the positive electrode lead 20 and is in contact with the surface of the positive electrode lead 20. That is, the insulating tape 50 is not attached to the positive electrode lead 20. The insulating tape 50 may be attached to the exposed portion 32.

絶縁テープ５０は、正極リード２０と重なる幅方向中央部に接着層５２を有さないため、幅方向中央部で厚みが薄くなっており、正極リード２０及び絶縁テープ５０の厚みに起因して正極１１の第１面に形成される段差を小さくすることができる。即ち、絶縁テープ５０を用いることで段差が緩和される。ゆえに、電池の外部から強い衝撃力が加わった場合であっても、段差が形成された部分でセパレータ１３が破断して短絡が生じることを防止できる。 Since the insulating tape 50 does not have an adhesive layer 52 in the central portion in the width direction that overlaps with the positive electrode lead 20, the thickness is thin in the central portion in the width direction, and the positive electrode is due to the thickness of the positive electrode lead 20 and the insulating tape 50. The step formed on the first surface of 11 can be reduced. That is, the step is relaxed by using the insulating tape 50. Therefore, even when a strong impact force is applied from the outside of the battery, it is possible to prevent the separator 13 from breaking at the portion where the step is formed and causing a short circuit.

絶縁テープ５０では、上述のように、基材５１の幅方向両側のみに接着層５２が設けられる。このため、接着層５２が設けられない領域５３が存在する絶縁テープ５０の幅方向中央部には、接着層５２によって挟まれた溝状の凹部が形成される。接着層５２は、例えば基材５１の長手方向全長にわたって、基材５１の幅方向両端から、それぞれ同じ幅で設けられる。この場合、溝状の凹部は、絶縁テープ５０の長手方向全長にわたって一定の幅で形成される。 In the insulating tape 50, as described above, the adhesive layers 52 are provided only on both sides of the base material 51 in the width direction. Therefore, a groove-shaped recess sandwiched by the adhesive layer 52 is formed in the central portion in the width direction of the insulating tape 50 in which the region 53 in which the adhesive layer 52 is not provided exists. The adhesive layer 52 is provided, for example, over the entire length of the base material 51 in the longitudinal direction from both ends in the width direction of the base material 51 with the same width. In this case, the groove-shaped recess is formed with a constant width over the entire length of the insulating tape 50 in the longitudinal direction.

絶縁テープ５０の幅Ｗ１は、例えば正極リード２０の幅Ｗの２倍〜３倍であり、一例としては５ｍｍ〜１０ｍｍである。領域５３（溝状の凹部）の幅Ｗ２は、正極リード２０の幅Ｗの１倍以上であり、好ましくは１．０５倍〜１．５０倍、より好ましくは１．１０倍〜１．２０倍である。この場合、正極１１に対する絶縁テープ５０の良好な接着力を確保しながら、接着層５２が正極リード２０と重ならないように絶縁テープ５０を配置できる。絶縁テープ５０は、正極リード２０が当該凹部に嵌るように貼着されている。 The width W1 of the insulating tape 50 is, for example, twice to three times the width W of the positive electrode lead 20, and is, for example, 5 mm to 10 mm. The width W2 of the region 53 (groove-shaped recess) is 1 times or more the width W of the positive electrode lead 20, preferably 1.05 times to 1.50 times, and more preferably 1.10 times to 1.20 times. Is. In this case, the insulating tape 50 can be arranged so that the adhesive layer 52 does not overlap with the positive electrode lead 20 while ensuring a good adhesive force of the insulating tape 50 to the positive electrode 11. The insulating tape 50 is attached so that the positive electrode lead 20 fits into the recess.

［負極］
負極１２は、上述の通り、負極芯体４０と、負極芯体４０の表面に設けられた負極合剤層４１とを有する。また、負極１２には、電極体１４の外周面に対応する部分に、負極芯体４０の表面が露出した露出部４２が形成されている。負極芯体４０には、銅など負極１２の電位範囲で安定な金属の箔、当該金属を表層に配置したフィルム等を用いることができる。負極合剤層４１は、負極活物質及び結着剤を含み、例えば負極リードが接続される部分及び露出部４２を除く負極芯体４０の両面に設けられることが好ましい。負極合剤層４１の厚みは、負極芯体４０の片側で、例えば５０μｍ〜１５０μｍである。負極１２は、例えば負極芯体４０の表面に負極活物質、及び結着剤等を含む負極合剤スラリーを塗布し、塗膜を乾燥させた後、圧縮して負極合剤層４１を負極芯体４０の両面に形成することにより作製できる。 [Negative electrode]
As described above, the negative electrode 12 has a negative electrode core body 40 and a negative electrode mixture layer 41 provided on the surface of the negative electrode core body 40. Further, the negative electrode 12 is formed with an exposed portion 42 in which the surface of the negative electrode core body 40 is exposed at a portion corresponding to the outer peripheral surface of the electrode body 14. For the negative electrode core body 40, a foil of a metal such as copper that is stable in the potential range of the negative electrode 12, a film on which the metal is arranged on the surface layer, or the like can be used. The negative electrode mixture layer 41 contains a negative electrode active material and a binder, and is preferably provided on both sides of the negative electrode core body 40 excluding the portion to which the negative electrode lead is connected and the exposed portion 42, for example. The thickness of the negative electrode mixture layer 41 is, for example, 50 μm to 150 μm on one side of the negative electrode core body 40. For the negative electrode 12, for example, a negative electrode mixture slurry containing a negative electrode active material, a binder and the like is applied to the surface of the negative electrode core body 40, the coating film is dried, and then compressed to compress the negative electrode mixture layer 41 into the negative electrode core. It can be produced by forming it on both sides of the body 40.

負極合剤層４１には、負極活物質として、例えばリチウムイオンを可逆的に吸蔵、放出する炭素系活物質が含まれる。好適な炭素系活物質は、鱗片状黒鉛、塊状黒鉛、土状黒鉛等の天然黒鉛、塊状人造黒鉛（ＭＡＧ）、黒鉛化メソフェーズカーボンマイクロビーズ（ＭＣＭＢ）等の人造黒鉛などの黒鉛である。また、負極活物質には、Ｓｉ及びＳｉ含有化合物の少なくとも一方で構成されるＳｉ系活物質が用いられてもよく、炭素系活物質とＳｉ系活物質が併用されてもよい。 The negative electrode mixture layer 41 contains, for example, a carbon-based active material that reversibly occludes and releases lithium ions as the negative electrode active material. Suitable carbon-based active materials are natural graphite such as scaly graphite, massive graphite, earthy graphite, and graphite such as artificial graphite such as massive artificial graphite (MAG) and graphitized mesophase carbon microbeads (MCMB). Further, as the negative electrode active material, a Si-based active material composed of at least one of Si and a Si-containing compound may be used, or a carbon-based active material and a Si-based active material may be used in combination.

負極合剤層４１に含まれる結着剤には、正極１１の場合と同様に、フッ素樹脂、ＰＡＮ、ポリイミド樹脂、アクリル樹脂、ポリオレフィン樹脂等を用いることもできるが、スチレン−ブタジエンゴム（ＳＢＲ）を用いることが好ましい。また、負極合剤層４１は、更に、ＣＭＣ又はその塩、ポリアクリル酸（ＰＡＡ）又はその塩、ポリビニルアルコール（ＰＶＡ）などを含むことが好ましい。中でも、ＳＢＲと、ＣＭＣ又はその塩、ＰＡＡ又はその塩を併用することが好適である。 As the binder contained in the negative electrode mixture layer 41, fluororesin, PAN, polyimide resin, acrylic resin, polyolefin resin and the like can be used as in the case of the positive electrode 11, but styrene-butadiene rubber (SBR) It is preferable to use. Further, the negative electrode mixture layer 41 preferably further contains CMC or a salt thereof, polyacrylic acid (PAA) or a salt thereof, polyvinyl alcohol (PVA) and the like. Above all, it is preferable to use SBR in combination with CMC or a salt thereof, PAA or a salt thereof.

なお、正極１１及び負極１２に、又は負極１２のみに、リードを覆う絶縁テープ５０が設けられていてもよい。負極リードが設けられる場合、負極リードと重なる基材５１の幅方向中央部には、接着層５２が存在しない領域５３が負極リードの幅以上の幅で形成される。絶縁テープ５０の領域５３が形成された部分は、接着層５２によって挟まれた溝状の凹部となる。絶縁テープ５０は、負極リードが当該凹部に嵌るように貼着される。 The insulating tape 50 covering the leads may be provided on the positive electrode 11 and the negative electrode 12, or only on the negative electrode 12. When the negative electrode lead is provided, a region 53 in which the adhesive layer 52 does not exist is formed in the central portion in the width direction of the base material 51 that overlaps the negative electrode lead with a width equal to or larger than the width of the negative electrode lead. The portion of the insulating tape 50 on which the region 53 is formed becomes a groove-shaped recess sandwiched by the adhesive layer 52. The insulating tape 50 is attached so that the negative electrode lead fits into the recess.

［セパレータ］
セパレータ１３には、イオン透過性及び絶縁性を有する多孔性シートが用いられる。多孔性シートの具体例としては、微多孔薄膜、織布、不織布等が挙げられる。セパレータ１３の材質としては、ポリエチレン、ポリプロピレン等のオレフィン樹脂、セルロースなどが好適である。セパレータ１３は、単層構造、積層構造のいずれであってもよい。セパレータ１３の表面には、耐熱層などが形成されていてもよい。 [Separator]
For the separator 13, a porous sheet having ion permeability and insulating property is used. Specific examples of the porous sheet include a microporous thin film, a woven fabric, and a non-woven fabric. As the material of the separator 13, olefin resin such as polyethylene and polypropylene, cellulose and the like are suitable. The separator 13 may have either a single-layer structure or a laminated structure. A heat-resistant layer or the like may be formed on the surface of the separator 13.

以下、実施例により本開示を更に説明するが、本開示はこれらの実施例に限定されるものではない。 Hereinafter, the present disclosure will be further described with reference to Examples, but the present disclosure is not limited to these Examples.

＜実施例１＞
［正極の作製］
正極活物質として、一般式ＬｉＮｉ０．８８Ｃｏ０．０９Ａｌ０．０３Ｏ２ で表されるリチウム含有遷移金属複合酸化物を用いた。１００質量部の正極活物質と、１質量部のアセチレンブラックと、０．９質量部のポリフッ化ビニリデンとを混合し、分散媒としてＮ−メチル−２−ピロリドン（ＮＭＰ）を用いて、正極合剤スラリーを調製した。次に、当該正極合剤スラリーを厚みが１５μｍのアルミニウム箔からなる正極芯体の両面に塗布し、塗膜を乾燥、圧縮した後、所定の電極サイズに切断し、正極芯体の両面に正極合剤層が形成された正極（厚み０．１４４ｍｍ、幅６２．６ｍｍ、長さ８６１ｍｍ）を作製した。なお、正極の長手方向中央部に芯体表面が露出した露出部を設け、当該露出部に幅３．５ｍｍの正極リードを溶接した。 <Example 1>
[Preparation of positive electrode]
As the positive electrode active material, a lithium-containing transition metal composite oxide represented by the general formula LiNi 0.88 Co 0.09 Al 0.03 O 2 was used. 100 parts by mass of positive electrode active material, 1 part by mass of acetylene black, and 0.9 parts by mass of polyvinylidene fluoride are mixed, and N-methyl-2-pyrrolidone (NMP) is used as a dispersion medium. An agent slurry was prepared. Next, the positive electrode mixture slurry is applied to both sides of a positive electrode core made of an aluminum foil having a thickness of 15 μm, the coating film is dried and compressed, cut to a predetermined electrode size, and positive electrodes are formed on both sides of the positive electrode core. A positive electrode (thickness 0.144 mm, width 62.6 mm, length 861 mm) on which the mixture layer was formed was prepared. An exposed portion with an exposed core surface was provided at the center of the positive electrode in the longitudinal direction, and a positive electrode lead having a width of 3.5 mm was welded to the exposed portion.

［絶縁テープの貼着］
絶縁テープとして、ポリイミド製の基材と、基材の裏面に設けられた、室温で粘着性を有する接着層とを含む粘着テープを用いた。接着層は基材の幅方向両側のみに設けられ、基材の幅方向中央部には接着層が存在しない領域（凹部）が３．５ｍｍの幅で形成されている。正極の正極リードが溶接された面に対して、正極リード及び露出部が覆われ、且つ正極リードがテープの裏面に形成された凹部に嵌るようにして、絶縁テープを貼着した。 [Attachment of insulating tape]
As the insulating tape, an adhesive tape containing a polyimide base material and an adhesive layer provided on the back surface of the base material and having adhesiveness at room temperature was used. The adhesive layer is provided only on both sides in the width direction of the base material, and a region (recess) in which the adhesive layer does not exist is formed in the central portion in the width direction of the base material with a width of 3.5 mm. The insulating tape was attached so that the positive electrode lead and the exposed portion were covered with respect to the welded surface of the positive electrode lead of the positive electrode, and the positive electrode lead was fitted into the recess formed on the back surface of the tape.

［負極の作製］
負極活物質として、９５質量部の黒鉛粉末、及び５質量部のＳｉＯｘで表されるシリコン酸化物の混合粉末を用いた。１００質量部の負極活物質と、１質量部のカルボキシメチルセルロース（ＣＭＣ）と、１質量部のスチレン−ブタジエンゴム（ＳＢＲ）とを混合し、分散媒として水を用いて、負極合剤スラリーを調製した。次に、当該負極合剤スラリーを銅箔からなる負極芯体の両面に塗布し、塗膜を乾燥、圧縮した後、所定の電極サイズに切断し、負極芯体の両面に負極合剤層が形成された負極（厚み０．１６０ｍｍ、幅６４．２ｍｍ、長さ９５９ｍｍ）を作製した。なお、負極の長手方向両端部に芯体表面が露出した露出部を設け、一方の露出部に負極リードを溶接した。 [Preparation of negative electrode]
As the negative electrode active material, 95 parts by mass of graphite powder and 5 parts by mass of a mixed powder of silicon oxide represented by SiO x were used. A negative electrode mixture slurry is prepared by mixing 100 parts by mass of the negative electrode active material, 1 part by mass of carboxymethyl cellulose (CMC), and 1 part by mass of styrene-butadiene rubber (SBR), and using water as a dispersion medium. did. Next, the negative electrode mixture slurry is applied to both sides of the negative electrode core made of copper foil, the coating film is dried and compressed, and then cut into a predetermined electrode size to form negative electrode mixture layers on both sides of the negative electrode core. The formed negative electrode (thickness 0.160 mm, width 64.2 mm, length 959 mm) was produced. An exposed portion with an exposed core surface was provided at both ends in the longitudinal direction of the negative electrode, and a negative electrode lead was welded to one exposed portion.

［非水電解液の調製］
エチレンカーボネート（ＥＣ）と、ジメチルカーボネート（ＤＭＣ）とを、１：３の体積比で混合した非水溶媒に、ビニレンカーボネート（ＶＣ）を５質量％の濃度で添加し、ＬｉＰＦ６を１．５ｍｏｌ／Ｌの濃度で溶解して、非水電解液を調製した。 [Preparation of non-aqueous electrolyte solution]
Vinylene carbonate (VC) was added at a concentration of 5% by mass to a non-aqueous solvent in which ethylene carbonate (EC) and dimethyl carbonate (DMC) were mixed at a volume ratio of 1: 3, and 1.5 mol of LiPF 6 was added. A non-aqueous electrolyte was prepared by dissolving at a concentration of / L.

［電池の作製］
上記正極と上記負極を、ポリエチレン製のセパレータを介して渦巻状に巻回することにより、巻回型の電極体を作製した。このとき、正極合剤層がセパレータを介して負極合剤層と対向するように、また負極の露出部（負極リードが存在しない露出部）が電極体の外周面を構成するように、各電極及びセパレータを巻回した。電極体の上下に絶縁板をそれぞれ配置した後、負極リードを有底円筒形状の外装缶の底部内面に溶接し、正極リードを封口体の内部端子板に溶接して、電極体を外装缶内に収容した。その後、外装缶内に非水電解液を減圧方式で注入し、ガスケットを介して外装缶の開口を封口体で封止することにより、円筒形の非水電解質二次電池（容量４６００ｍＡｈ）を作製した。 [Battery production]
A wound electrode body was produced by spirally winding the positive electrode and the negative electrode through a polyethylene separator. At this time, each electrode is formed so that the positive electrode mixture layer faces the negative electrode mixture layer via the separator and the exposed portion of the negative electrode (exposed portion in which the negative electrode lead does not exist) constitutes the outer peripheral surface of the electrode body. And the separator was wound. After arranging insulating plates on the top and bottom of the electrode body, the negative electrode lead is welded to the inner surface of the bottom of the bottomed cylindrical outer can, the positive electrode lead is welded to the inner terminal plate of the sealing body, and the electrode body is inside the outer can. Housed in. After that, a non-aqueous electrolyte solution is injected into the outer can by a reduced pressure method, and the opening of the outer can is sealed with a sealing body via a gasket to prepare a cylindrical non-aqueous electrolyte secondary battery (capacity: 4600 mAh). did.

＜実施例２＞
絶縁テープの凹部の幅を３．７ｍｍ（正極リードの幅の１．０５７倍）に変更したこと以外は、実施例１と同様にして円筒形の非水電解質二次電池を作製した。 <Example 2>
A cylindrical non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the width of the recess of the insulating tape was changed to 3.7 mm (1.057 times the width of the positive electrode lead).

＜実施例３＞
絶縁テープの凹部の幅を４．０ｍｍ（正極リードの幅の１．１４３倍）に変更したこと以外は、実施例１と同様にして円筒形の非水電解質二次電池を作製した。 <Example 3>
A cylindrical non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the width of the recess of the insulating tape was changed to 4.0 mm (1.143 times the width of the positive electrode lead).

＜比較例１＞
絶縁テープの裏面全体に接着層を設けて凹部を形成しなかったこと以外は、実施例１と同様にして円筒形の非水電解質二次電池を作製した。 <Comparative example 1>
A cylindrical non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that an adhesive layer was provided on the entire back surface of the insulating tape to form no recesses.

＜比較例２＞
絶縁テープの凹部の幅を３．０ｍｍに変更したこと以外は、実施例１と同様にして円筒形の非水電解質二次電池を作製した。 <Comparative example 2>
A cylindrical non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the width of the recess of the insulating tape was changed to 3.0 mm.

［インパクト試験］
実施例及び比較例の各電池について、電池を横切るように直径１５．８ｍｍの丸棒を高さ方向中央に配置し、丸棒の鉛直上方６１±２．５ｃｍの高さから、質量９．１ｋｇの錘を落下させて電池に衝撃を加えた。インパクト試験後の各電池について、内部短絡の有無を確認した結果を表１に示す。 [Impact test]
For each of the batteries of Examples and Comparative Examples, a round bar having a diameter of 15.8 mm was arranged in the center in the height direction so as to cross the battery, and the mass was 9.1 kg from a height of 61 ± 2.5 cm vertically above the round bar. The weight of the battery was dropped to give a shock to the battery. Table 1 shows the results of confirming the presence or absence of an internal short circuit for each battery after the impact test.

Figure 2020149881
Figure 2020149881

表１に示すように、インパクト試験において、比較例の電池では内部短絡が確認されたのに対して、実施例の電池では内部短絡が確認されなかった。即ち、リードと重なるテープ基材の幅方向中央部に接着層が存在しない領域がリードの幅以上の幅で形成された絶縁テープを用いることにより、電池が変形するような強い衝撃力が外部から加わった場合においても、内部短絡の発生を防止できる。 As shown in Table 1, in the impact test, an internal short circuit was confirmed in the battery of the comparative example, whereas an internal short circuit was not confirmed in the battery of the example. That is, by using an insulating tape in which the region where the adhesive layer does not exist in the central portion of the tape base material that overlaps with the lead is formed with a width equal to or larger than the width of the lead, a strong impact force that deforms the battery is applied from the outside. Even if it is added, the occurrence of an internal short circuit can be prevented.

１０ 二次電池、１１ 正極、１２ 負極、１３ セパレータ、１４ 電極体、１６ 外装缶、１７ 封口体、１８，１９ 絶縁板、２０ 正極リード、２１ 溝入部、２３ 内部端子板、２４ 下弁体、２５ 絶縁部材、２６ 上弁体、２７ キャップ、２８ ガスケット、３０ 正極芯体、３１ 正極合剤層、３２，４２ 露出部、４０ 負極芯体、４１ 負極合剤層、５０ 絶縁テープ、５１ 基材、５２ 接着層、５３ 領域 10 Rechargeable battery, 11 Positive electrode, 12 Negative electrode, 13 Separator, 14 Electrode body, 16 Exterior can, 17 Seal body, 18, 19 Insulation plate, 20 Positive electrode lead, 21 Grooved part, 23 Internal terminal plate, 24 Lower valve body, 25 Insulation member, 26 Upper valve body, 27 Cap, 28 Gasket, 30 Positive electrode core, 31 Positive electrode mixture layer, 32, 42 Exposed part, 40 Negative electrode core, 41 Negative electrode mixture layer, 50 Insulation tape, 51 Base material , 52 Adhesive layer, 53 areas

Claims (4)

正極と負極がセパレータを介して巻回された電極体を備える二次電池において、
前記正極及び前記負極は、芯体と、前記芯体の表面に設けられた合剤層とを含み、
前記正極及び前記負極の少なくとも一方には、前記芯体の表面が露出した露出部に接続されるリードと、前記リード及び前記露出部を覆う絶縁テープとが設けられ、
前記絶縁テープは、基材と、前記基材の一方の面に設けられた接着層とを含み、
前記基材の一方の面において、前記接着層は前記基材の幅方向両側に設けられ、前記リードと重なる前記基材の幅方向中央部には、前記接着層が存在しない領域が前記リードの幅以上の幅で形成されている、二次電池。 In a secondary battery including an electrode body in which a positive electrode and a negative electrode are wound via a separator,
The positive electrode and the negative electrode include a core body and a mixture layer provided on the surface of the core body.
At least one of the positive electrode and the negative electrode is provided with a lead connected to an exposed portion where the surface of the core body is exposed, and an insulating tape covering the lead and the exposed portion.
The insulating tape includes a base material and an adhesive layer provided on one surface of the base material.
On one surface of the base material, the adhesive layers are provided on both sides in the width direction of the base material, and a region in which the adhesive layer does not exist is a region of the lead in the central portion in the width direction of the base material that overlaps with the lead. A secondary battery that is formed with a width greater than or equal to the width. 前記絶縁テープは、前記正極に貼着されている、請求項１に記載の二次電池。 The secondary battery according to claim 1, wherein the insulating tape is attached to the positive electrode. 前記露出部は、前記正極の長手方向中央部に形成されている、請求項２に記載の二次電池。 The secondary battery according to claim 2, wherein the exposed portion is formed in the central portion in the longitudinal direction of the positive electrode. 前記領域の幅は、前記リードの幅の１．０５倍〜１．５０倍である、請求項１〜３のいずれか１項に記載の二次電池。 The secondary battery according to any one of claims 1 to 3, wherein the width of the region is 1.05 times to 1.50 times the width of the lead.
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