JP2019102258A - Power storage element - Google Patents
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- 239000007773 negative electrode material Substances 0.000 claims description 41
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- 239000000463 material Substances 0.000 description 9
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- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 8
- 229910001416 lithium ion Inorganic materials 0.000 description 8
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- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
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Classifications
-
- 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
- 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
- Y02E60/13—Energy storage using capacitors
-
- 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
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- Secondary Cells (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Electric Double-Layer Capacitors Or The Like (AREA)
- Primary Cells (AREA)
Abstract
Description
本発明は、電極とセパレータとを含む電極体を備える蓄電素子に関する。 The present invention relates to a storage element provided with an electrode assembly including an electrode and a separator.
従来から、負極電極板及び正極電極板の一方の電極板がつづら折り状に積層されているリチウムイオン二次電池（以下、単に「電池」と称する）が知られている（特許文献１参照）。具体的に、この電池は、図１１に示すように、負極電極板５０１と、正極電極板５０４と、両電極板５０１、５０４間に挿入されたセパレータ５０７とが、交互に積層されて構成された電極積層体である。 Conventionally, a lithium ion secondary battery (hereinafter, simply referred to as "battery") in which one electrode plate of a negative electrode plate and a positive electrode plate is stacked in a zigzag manner is known (see Patent Document 1). Specifically, as shown in FIG. 11, this battery is configured by alternately laminating a negative electrode plate 501, a positive electrode plate 504, and separators 507 inserted between both electrode plates 501 and 504. Electrode stack.
負極電極板５０１は、両面でセパレータ５０７と密着しており、長手方向に所定間隔で交互に折り畳まれてつづら折り状に積層された長尺の可撓性材料からなる電極板（長尺電極板と称する）である。負極の長尺電極板５０１は、銅箔５０２の両面に形成された負極活物質層５０３をもち、つづら折りの折り目の延伸方向に沿った両方向のうち一方へ突出した一方端子部たる負極端子部をもつ。負極端子部は、銅箔５０２だけであり、そのいずれの面にも負極活物質層５０３は形成されていない。 The negative electrode plate 501 is in close contact with the separator 507 on both sides, and is an electrode plate made of a long flexible material that is alternately folded at predetermined intervals in the longitudinal direction and stacked in a zigzag manner (a long electrode plate Is called). A long electrode plate 501 of a negative electrode has a negative electrode active material layer 503 formed on both sides of a copper foil 502, and has a negative electrode terminal portion which is one terminal portion which protrudes in one of two directions along the extension direction of a serpentine fold. Have. The negative electrode terminal portion is only the copper foil 502, and the negative electrode active material layer 503 is not formed on any surface thereof.
セパレータ５０７は、長尺の絶縁膜からなり、その厚さ方向に電荷の移動が可能な電池用セパレータである。このセパレータ５０７は、負極の長尺電極板５０１の両面に接して折り畳まれている。具体的に、セパレータ５０７は、長尺電極板５０１の銅箔５０２のうち、負極活物質層５０３の形成されている部分を両面から包み込んでいる。即ち、長尺電極板５０１とその両面を包むセパレータ５０７とは長尺物５０８を形成している。 The separator 507 is made of a long insulating film, and is a battery separator capable of moving charges in the thickness direction. The separator 507 is folded in contact with both sides of the long electrode plate 501 of the negative electrode. Specifically, the separator 507 wraps the portion of the copper foil 502 of the long electrode plate 501 on which the negative electrode active material layer 503 is formed from both sides. That is, the long electrode plate 501 and the separator 507 which wraps the both sides thereof form the long object 508.
正極電極板５０４は、両面でセパレータ５０７に密着しており、多数の互いに独立した短冊形状の電極板（短冊状電極板と称する）である。正極の各短冊状電極板５０４は、アルミニウム箔５０５の両面に形成された正極活物質層５０６をもち、前記折り目の延伸方向に沿った両方向のうち他方へ突出した他方端子部たる正極端子部をもつ。正極端子部は、アルミニウム箔５０５からなり、そのいずれの面にも正極活物質層５０６は形成されていない。 The positive electrode plate 504 is in close contact with the separator 507 on both sides, and is a large number of mutually independent strip-shaped electrode plates (referred to as strip-shaped electrode plates). Each strip-like electrode plate 504 of the positive electrode has a positive electrode active material layer 506 formed on both sides of the aluminum foil 505, and the positive electrode terminal portion which is the other terminal portion protruding in the other of both directions along the stretching direction of the fold Have. The positive electrode terminal portion is made of an aluminum foil 505, and the positive electrode active material layer 506 is not formed on any surface thereof.
そして、長尺電極板５０１とセパレータ５０７とからなる長尺物５０８に対し、その両側から多数の短冊状電極板５０４が交互に積層されて電池５００が構成されている。即ち、一枚の長尺物５０８と多数の短冊状電極板５０４との積層に際し、長尺物５０８はつづら折りに折り畳まれ、その間に短冊状電極板５０４が両側から挿入されて長尺物５０８に挟持された構造を電池５００は持っている。 Then, a plurality of strip-like electrode plates 504 are alternately stacked on both sides of a long object 508 consisting of the long electrode plate 501 and the separator 507 to form a battery 500. That is, when stacking one long material 508 and a large number of strip electrode plates 504, the long material 508 is folded in a serpentine manner, and the long strip material electrode plate 504 is inserted between the long materials 508 in between. The battery 500 has a sandwiched structure.
以上の電池５００では、短冊状電極板５０４は、つづら折りに折り畳まれた長尺物５０８に挟まれているだけであるため、電池５００に振動等が加わったときに、正極端子部が長尺物５０８の内側（つづら折りに折り畳まれた部位の内側）に入り込む方向にずれる場合がある。このとき、セパレータ５０７も短冊状電極板５０４と共にずれると、正極端子部（アルミニウム箔５０５）と負極活物質層５０３とが接触して短絡する。 In the above battery 500, since the strip-like electrode plate 504 is only sandwiched by the long material 508 folded in a zigzag manner, the positive electrode terminal portion is long when vibration or the like is applied to the battery 500. There is a possibility of shifting in the direction of getting inward of 508 (inside of the serpentine folded part). At this time, when the separator 507 is also displaced together with the strip-like electrode plate 504, the positive electrode terminal portion (aluminum foil 505) and the negative electrode active material layer 503 come into contact with each other to cause a short circuit.
そこで、本実施形態は、電極体においてセパレータを介して隣り合う電極の一方の電極の活物質層非形成部と他方の電極の活物質層形成部との短絡が抑えられる蓄電素子を提供することを目的とする。 Therefore, the present embodiment provides an energy storage device capable of suppressing a short circuit between the active material layer non-forming portion of one of the adjacent electrodes and the active material layer forming portion of the other electrode in the electrode body via the separator. With the goal.
本実施形態の蓄電素子は、
金属箔及び活物質層が重ねられる活物質層形成部と金属箔に活物質層が重ねられない活物質層非形成部とが第一方向に並ぶ電極と、
前記第一方向の寸法が前記活物質層形成部より大きなセパレータと、を有する電極体を備え、
前記電極と前記セパレータとは、前記活物質層非形成部が前記セパレータにおける前記第一方向の端縁から突出するように積層され、
前記活物質層非形成部は、該活物質層非形成部における前記セパレータの前記第一方向の端縁から突出している部位から延び且つ前記第一方向から見て前記端縁と重なる部位を有する延出部を備える。
The storage element of the present embodiment is
An electrode in which an active material layer forming portion on which a metal foil and an active material layer are superimposed and an active material layer non-forming portion on which the active material layer can not be superimposed on the metal foil are arranged in a first direction
An electrode body having a separator whose dimension in the first direction is larger than that of the active material layer forming portion,
The electrode and the separator are stacked such that the active material layer non-forming portion protrudes from an end edge of the separator in the first direction,
The active material layer non-forming portion extends from a portion of the active material layer non-forming portion that protrudes from the edge of the first direction of the separator and has a portion overlapping with the edge when viewed from the first direction It has an extension part.
かかる構成によれば、活物質層非形成部がセパレータ側に向かう向きに電極が移動し又は移動しようとしたときに、延出部がセパレータの第一方向の端縁に当接し又は当接していることで、それ以上の前記方向への電極の移動が規制され、これにより、セパレータを介して隣り合う電極の一方の電極の活物質層形成部と他方の電極の活物質層非形成部とが対向し難くなる。その結果、前記隣り合う電極の間に配置されたセパレータがずれ又は損傷等しても、前記一方の電極の活物質層非形成部と前記他方の電極の活物質層形成部との間での短絡の発生が抑えられる。 According to this configuration, when the electrode moves or moves in the direction toward the separator side, the extension portion abuts or abuts on the first edge of the separator. Therefore, the movement of the electrode in the further direction is restricted, whereby the active material layer forming portion of one electrode and the active material layer non-forming portion of the other electrode adjacent to each other with the separator interposed therebetween. Is difficult to face. As a result, even if the separators disposed between the adjacent electrodes are displaced or damaged, it may occur between the active material layer non-forming portion of the one electrode and the active material layer forming portion of the other electrode. The occurrence of short circuit is suppressed.
前記蓄電素子では、
前記活物質層非形成部は、前記突出している部位と前記延出部との境界位置で曲がっている当該活物質層非形成部の端縁の前記境界位置を含む領域において前記金属箔に重ねられたコート層を有してもよい。
In the storage element,
The active material layer non-forming portion overlaps the metal foil in a region including the boundary position of the edge of the active material layer non-forming portion bent at the boundary position between the projecting portion and the extension portion. It may have a coated layer.
このように、活物質層非形成部においてセパレータから突出している部位と延出部との境界位置で曲がっている端縁の前記境界位置を含む領域にコート層が重ねられているため、延出部がセパレータの端縁に当接した状態で電極がセパレータ側に移動しようとしたときに応力が集中し易い部位（端縁の曲がっている部位）からの裂けが抑えられる。 As described above, since the coating layer is superimposed on the region including the boundary position of the edge bent at the boundary position between the portion protruding from the separator and the extension portion in the active material layer non-forming portion, When the electrode tries to move to the separator side with the portion in contact with the edge of the separator, tearing from a portion where stress is likely to be concentrated (a portion where the edge is bent) is suppressed.
前記蓄電素子では、
前記セパレータは、平行若しくは略平行な一対の平坦部と、前記第一方向に延びるターン軸周りで方向転換するように前記一対の平坦部の端部同士を接続するターン部と、を含む折り返し部を有し、
前記電極は、前記一対の平坦部の間に配置され、
前記延出部は、前記ターン部における前記第一方向の一方側の端縁より一方側に配置されてもよい。
In the storage element,
The separator includes a folded portion including a pair of parallel or substantially parallel flat portions, and a turn portion connecting ends of the pair of flat portions so as to turn around a turn axis extending in the first direction. Have
The electrode is disposed between the pair of flat portions,
The extending portion may be disposed on one side of an end edge on one side in the first direction of the turn portion.
ターン部ではターン軸方向（第一方向）からの力に対する強度が向上しているため、該ターン部にターン軸方向から延出部を当接させることで、延出部がセパレータ（ターン部）の端縁に当接した状態で電極がセパレータ側へ移動しようとしたときの該セパレータの変形が抑えられ、これにより、電極のセパレータ側への移動がより確実に抑えられる。 Since the strength against the force from the turn axial direction (first direction) is improved in the turn portion, the extension portion is a separator (turn portion) by bringing the extension portion into contact with the turn portion from the turn axial direction. The deformation of the separator when the electrode tries to move to the separator side in the state of being in contact with the end edge of the electrode is suppressed, whereby the movement of the electrode to the separator side is more reliably suppressed.
また、前記蓄電素子では、
前記折り返し部は、前記第一方向と直交する第二方向の一方側が開放された第一の折り返し部と、前記第二方向の他方側が開放された第二の折り返し部と、を含み、
前記セパレータは、前記第一の折り返し部と前記第二の折り返し部とが交互に配置されたつづら折り状態であり、
前記電極は、前記第一の折り返し部の内側と前記第二の折り返し部の内側とのそれぞれに配置されてもよい。
Further, in the storage element,
The folded portion includes a first folded portion in which one side of a second direction orthogonal to the first direction is opened, and a second folded portion in which the other side of the second direction is opened,
The separator is in a zigzag state in which the first folded portion and the second folded portion are alternately arranged;
The electrodes may be disposed on the inner side of the first folded portion and the inner side of the second folded portion.
かかる構成によれば、第二方向の一方側の端部と他方側の端部とにターン部が配置されるため、ターン軸方向からの力に対する電極体の強度が向上する。しかも、第一の折り返し部の内側と第二の折り返し部の内側とに配置された各電極のセパレータ側への移動（セパレータの第一方向の端縁から突出している部位の折り返し部内側への入り込み）も確実に抑えられる。 According to this configuration, since the turn portion is disposed at the end on one side and the end on the other side in the second direction, the strength of the electrode body against the force in the direction of the turn axis is improved. In addition, movement of the electrodes disposed on the inner side of the first folded portion and the inner side of the second folded portion toward the separator (into the folded portion of the portion projecting from the edge of the separator in the first direction) It can be reliably suppressed.
この場合、前記蓄電素子では、
前記電極は、正極であり、
前記電極体は、前記セパレータに重ねられ且つ該セパレータと共につづら折り状態である負極を有し、
前記負極では、金属箔及び負極活物質層が重ねられる負極活物質層形成部と金属箔に負極活物質層が重ねられない負極活物質層非形成部とが第一方向に並び、
前記負極活物質層形成部は、前記セパレータと重なっていてもよい。
In this case, in the storage element,
The electrode is a positive electrode,
The electrode body has a negative electrode that is superimposed on the separator and is in a zigzag state with the separator,
In the negative electrode, a negative electrode active material layer forming portion on which the metal foil and the negative electrode active material layer are stacked, and a negative electrode active material layer non-forming portion on which the negative electrode active material layer can not be stacked on the metal foil are arranged in the first direction.
The negative electrode active material layer forming portion may overlap with the separator.
かかる構成によれば、正極の活物質層非形成部が各折り返し部の内側へ入り込むのが抑えられ（即ち、正極の活物質層非形成部と負極の負極活物質層形成部とがセパレータを介して対向することが防がれ）、これにより、セパレータの位置ずれや損傷等による正極の活物質層非形成部と負極の負極活物質層形成部との短絡が抑えられる。 According to this configuration, the active material layer non-forming portion of the positive electrode is prevented from entering the inside of each folded portion (that is, the active material layer non-forming portion of the positive electrode and the negative electrode active material layer forming portion of the negative electrode This prevents the short circuit between the active material layer non-forming portion of the positive electrode and the negative electrode active material layer forming portion of the negative electrode due to displacement or damage of the separator.
以上より、本実施形態によれば、電極体においてセパレータを介して隣り合う電極の一方の電極の活物質層非形成部と他方の電極の活物質層形成部との短絡が抑えられる蓄電素子を提供することができる。 As described above, according to the present embodiment, a storage element in which a short circuit between the active material layer non-forming portion of one electrode and the active material layer forming portion of the other electrode in adjacent electrodes in the electrode body is suppressed. Can be provided.
以下、本発明に係る蓄電素子の一実施形態について、図１〜図８を参照しつつ説明する。蓄電素子には、一次電池、二次電池、キャパシタ等がある。本実施形態では、蓄電素子の一例として、充放電可能な二次電池について説明する。尚、本実施形態の各構成部材（各構成要素）の名称は、本実施形態におけるものであり、背景技術における各構成部材（各構成要素）の名称と異なる場合がある。 Hereinafter, an embodiment of a storage element according to the present invention will be described with reference to FIGS. 1 to 8. The storage element includes a primary battery, a secondary battery, a capacitor and the like. In the present embodiment, a chargeable / dischargeable secondary battery will be described as an example of a storage element. In addition, the name of each component (each component) of this embodiment is in this embodiment, and may differ from the name of each component (each component) in background art.
本実施形態の蓄電素子は、非水電解質二次電池である。より詳しくは、蓄電素子は、リチウムイオンの移動に伴って生じる電子移動を利用したリチウムイオン二次電池である。この種の蓄電素子は、電気エネルギーを供給する。蓄電素子は、単一又は複数で使用される。具体的に、蓄電素子は、要求される出力及び要求される電圧が小さいときには、単一で使用される。一方、蓄電素子は、要求される出力及び要求される電圧の少なくとも一方が大きいときには、他の蓄電素子と組み合わされて蓄電装置に用いられる。前記蓄電装置では、該蓄電装置に用いられる蓄電素子が電気エネルギーを供給する。 The storage element of the present embodiment is a non-aqueous electrolyte secondary battery. More specifically, the storage element is a lithium ion secondary battery utilizing electron transfer that occurs as lithium ion moves. This type of storage element supplies electrical energy. The storage element is used singly or in plurality. Specifically, the storage element is used singly when the required output and the required voltage are small. On the other hand, when at least one of the required output and the required voltage is large, the storage element is used in the storage device in combination with another storage element. In the storage device, a storage element used for the storage device supplies electrical energy.
蓄電素子は、図２に示すように、電極体２を備える。また、蓄電素子１は、図１にも示すように、電極体２を収容するケース３と、少なくとも一部が外部に露出した状態でケース３に取り付けられる外部端子４と、電極体２と外部端子４とを接続する集電体５と、を備える。また、蓄電素子１は、電極体２とケース３との間に配置される絶縁部材７等も備える。本実施形態の蓄電素子１は、電極体２と集電体５との間に配置されるクリップ部材６も備える。尚、各図においては、構造を示すために、電極体２を構成する電極等の厚さを誇張して表す等、電極体２の構成を模式的に表している。 The storage element includes an electrode body 2 as shown in FIG. In addition, as shown also in FIG. 1, the storage element 1 has a case 3 for housing the electrode body 2, an external terminal 4 attached to the case 3 with at least a part exposed to the outside, the electrode body 2 and the outside. And a current collector 5 connected to the terminal 4. The storage element 1 also includes an insulating member 7 and the like disposed between the electrode body 2 and the case 3. The storage element 1 of the present embodiment also includes a clip member 6 disposed between the electrode body 2 and the current collector 5. In each of the drawings, in order to show the structure, the configuration of the electrode body 2 is schematically represented, for example, by exaggerating the thickness of an electrode or the like constituting the electrode body 2.
電極体２は、図３にも示すように、少なくともセパレータ２１５を含む第一部材２１と、第二の電極２２０を含む第二部材２２と、を有する。本実施形態の第一部材２１は、第二の電極２２０と極性の異なる第一の電極２１０も含む。即ち、本実施形態の第一部材２１は、第一の電極２１０とセパレータ２１５とを含む。この第一部材２１は、長尺であり、つづら折り状態に折り畳まれている。また、本実施形態の第二部材２２は、第二の電極２２０のみを含む。また、本実施形態の電極体２では、第一の電極２１０は、負極であり、第二の電極２２０は、正極である。 The electrode body 2 has a first member 21 including at least a separator 215, and a second member 22 including a second electrode 220, as also shown in FIG. The first member 21 of the present embodiment also includes a first electrode 210 different in polarity from the second electrode 220. That is, the first member 21 of the present embodiment includes the first electrode 210 and the separator 215. The first member 21 is long and folded in a zigzag manner. In addition, the second member 22 of the present embodiment includes only the second electrode 220. Moreover, in the electrode body 2 of the present embodiment, the first electrode 210 is a negative electrode, and the second electrode 220 is a positive electrode.
第一部材２１は、図４にも示すように、長尺な負極２１０と、負極２１０に重ねられるセパレータ２１５と、を有する。本実施形態の第一部材２１では、一対の長尺なセパレータ２１５が負極２１０を両面側から挟み込んでいる。即ち、第一部材２１は、一つの負極２１０と、この負極２１０を挟み込む一対のセパレータ２１５と、を有する。本実施形態の一対のセパレータ２１５は、互いに接合されていないが、負極２１０を挟み込んだ状態で互いに接合されていてもよい。 The first member 21 has a long negative electrode 210 and a separator 215 superimposed on the negative electrode 210, as also shown in FIG. In the first member 21 of the present embodiment, the pair of long separators 215 sandwich the negative electrode 210 from both sides. That is, the first member 21 has one negative electrode 210 and a pair of separators 215 sandwiching the negative electrode 210. The pair of separators 215 of the present embodiment is not bonded to each other, but may be bonded to each other with the negative electrode 210 interposed therebetween.
負極２１０は、金属箔２１１と、金属箔２１１の両面のそれぞれに重ねられる負極活物質層２１２と、を有する。即ち、負極２１０は、一つの金属箔２１１と一対の負極活物質層２１２とを有する。本実施形態の金属箔２１１は、例えば、銅箔である。この負極２１０は、長尺な帯状である。 The negative electrode 210 includes a metal foil 211 and a negative electrode active material layer 212 stacked on each of both sides of the metal foil 211. That is, the negative electrode 210 has one metal foil 211 and a pair of negative electrode active material layers 212. The metal foil 211 of the present embodiment is, for example, a copper foil. The negative electrode 210 is in the form of a long strip.
負極活物質層２１２は、負極活物質と、バインダーと、を有する。 The negative electrode active material layer 212 includes a negative electrode active material and a binder.
負極活物質は、例えば、グラファイト、難黒鉛化炭素、及び易黒鉛化炭素などの炭素材、又は、ケイ素（Ｓｉ）及び錫（Ｓｎ）などのリチウムイオンと合金化反応を生じる材料である。本実施形態の負極活物質は、グラファイトである。 The negative electrode active material is, for example, a carbon material such as graphite, non-graphitizable carbon, and graphitizable carbon, or a material that causes an alloying reaction with lithium ions such as silicon (Si) and tin (Sn). The negative electrode active material of the present embodiment is graphite.
負極活物質層２１２に用いられるバインダーは、例えば、ポリフッ化ビニリデン（ＰＶＤＦ）、エチレンとビニルアルコールとの共重合体、ポリメタクリル酸メチル、ポリエチレンオキサイド、ポリプロピレンオキサイド、ポリビニルアルコール、ポリアクリル酸、ポリメタクリル酸、スチレンブタジエンゴム（ＳＢＲ）である。本実施形態のバインダーは、ポリフッ化ビニリデンである。 The binder used for the negative electrode active material layer 212 is, for example, polyvinylidene fluoride (PVDF), a copolymer of ethylene and vinyl alcohol, methyl polymethacrylate, polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyacrylic acid, polymethacryl Acid, styrene butadiene rubber (SBR). The binder of the present embodiment is polyvinylidene fluoride.
負極活物質層２１２は、ケッチェンブラック（登録商標）、アセチレンブラック、黒鉛等の導電助剤をさらに有してもよい。本実施形態の負極活物質層２１２は、導電助剤を有していない。 The negative electrode active material layer 212 may further have a conductive aid such as ketjen black (registered trademark), acetylene black, or graphite. The negative electrode active material layer 212 of the present embodiment has no conductive support agent.
この負極活物質層２１２を有する負極２１０は、長尺帯状の負極本体（負極活物質層形成部（活物質層形成部））２１３と、負極本体２１３から延びる負極タブ（負極活物質層非形成部（活物質層非形成部））２１４と、を有する。これら負極本体２１３と負極タブ２１４とは、所定の方向（第一方向）に並んでいる。本実施形態の負極２１０は、負極本体２１３の長手方向に間隔をあけて配置される複数の負極タブ２１４を有する。 The negative electrode 210 having the negative electrode active material layer 212 includes a long strip-like negative electrode main body (a negative electrode active material layer forming portion (active material layer forming portion)) 213 and a negative electrode tab (negative electrode active material layer not formed) extending from the negative electrode main body 213 Part (active material layer non-forming part) 214. The negative electrode body 213 and the negative electrode tab 214 are arranged in a predetermined direction (first direction). The negative electrode 210 of the present embodiment has a plurality of negative electrode tabs 214 spaced apart in the longitudinal direction of the negative electrode body 213.
負極本体２１３では、金属箔２１１と負極活物質層２１２とが重ねられている。具体的に、負極本体２１３は、長手方向の各位置において短手方向（幅方向）の寸法が一定の帯状の金属箔２１１と、金属箔２１１の両面の全域に重ねられる負極活物質層２１２と、を有する。 In the negative electrode main body 213, the metal foil 211 and the negative electrode active material layer 212 are stacked. Specifically, the negative electrode body 213 has a strip-like metal foil 211 having a constant dimension in the width direction at each position in the longitudinal direction, and a negative electrode active material layer 212 superimposed on the entire area of both surfaces of the metal foil 211. And.
複数の負極タブ２１４のそれぞれは、負極本体２１３の一方の長辺（幅方向の一方の端縁）２１３Ａから該負極本体２１３と離れる方向（幅方向）に延びている。複数の負極タブ２１４のそれぞれは、金属箔２１１を露出させている。即ち、各負極タブ２１４は、金属箔２１１のみによって構成されており、負極活物質層２１２を重ねられていない。複数の負極タブ２１４のそれぞれは、第一部材２１において、セパレータ２１５から幅方向に突出している。即ち、複数の負極タブ２１４のそれぞれは、セパレータ２１５の幅方向の一方の端縁から該幅方向に突出している。これら複数の負極タブ２１４のそれぞれは、第一部材２１（負極本体２１３）が折り畳まれた状態（つづら折り状態）において重なる位置に配置されている（図２参照）。 Each of the plurality of negative electrode tabs 214 extends from one long side (one end edge in the width direction) 213A of the negative electrode body 213 in a direction (width direction) away from the negative electrode body 213. Each of the plurality of negative electrode tabs 214 exposes the metal foil 211. That is, each negative electrode tab 214 is constituted only by the metal foil 211, and the negative electrode active material layer 212 is not overlapped. Each of the plurality of negative electrode tabs 214 protrudes in the width direction from the separator 215 in the first member 21. That is, each of the plurality of negative electrode tabs 214 protrudes in the width direction from one end edge of the separator 215 in the width direction. Each of the plurality of negative electrode tabs 214 is disposed at a position where the first member 21 (negative electrode main body 213) is overlapped in a folded state (swinged state) (see FIG. 2).
一対のセパレータ２１５のそれぞれは、絶縁性を有する部材であり、負極２１０と正極２２０との間に配置される。これにより、電極体２において、負極２１０と正極２２０とが互いに絶縁される。また、一対のセパレータ２１５のそれぞれは、ケース３内において、電解液を保持する。これにより、蓄電素子１の充放電時において、セパレータ２１５を挟んで対向する負極２１０と正極２２０との間を、リチウムイオンが移動可能となる。 Each of the pair of separators 215 is a member having an insulating property, and is disposed between the negative electrode 210 and the positive electrode 220. Thereby, in the electrode body 2, the negative electrode 210 and the positive electrode 220 are mutually insulated. Each of the pair of separators 215 holds the electrolytic solution in the case 3. Thereby, at the time of charge and discharge of the storage element 1, lithium ions can move between the negative electrode 210 and the positive electrode 220 facing each other across the separator 215.
一対のセパレータ２１５のそれぞれは、例えば、ポリエチレン、ポリプロピレン、セルロース、ポリアミドなどの多孔質膜によって構成される。本実施形態のセパレータ２１５は、ＳｉＯ２粒子、Ａｌ２Ｏ３粒子、ベーマイト（アルミナ水和物）等の無機粒子を含んだ無機層を、多孔質膜によって形成された基材の上に設けることで形成されている。本実施形態のセパレータ２１５の基材は、例えば、ポリエチレンによって形成される。 Each of the pair of separators 215 is formed of, for example, a porous film such as polyethylene, polypropylene, cellulose, or polyamide. In the separator 215 of this embodiment, an inorganic layer containing inorganic particles such as SiO 2 particles, Al 2 O 3 particles, and boehmite (alumina hydrate) is provided on a substrate formed of a porous film. It is formed of The base of the separator 215 of the present embodiment is formed of, for example, polyethylene.
これら一対のセパレータ２１５のそれぞれは、負極２１０と同様に、長尺な帯状である。具体的に、各セパレータ２１５において、短手方向の寸法（幅寸法）は、負極本体２１３の幅寸法より大きく且つ負極２１０における負極タブ２１４が設けられた部位（負極本体２１３と負極タブ２１４とを合わせた部位）の幅寸法より小さい。このため、一対のセパレータ２１５が負極２１０を挟み込むと、セパレータ２１５の幅方向の一方の長辺（端縁）から各負極タブ２１４が突出した状態となる。尚、以下では、一対のセパレータ２１５と、これら一対のセパレータ２１５に挟まれた負極２１０の部位とを、第一部材本体２１０Ａと称し、一対のセパレータ２１５の幅方向の一方の端縁から突出している負極タブ２１４の部位を第一部材タブ２１０Ｂと称することもある（図３参照）。 Similar to the negative electrode 210, each of the pair of separators 215 has a long strip shape. Specifically, in each separator 215, the dimension in the width direction (width dimension) is larger than the width dimension of the negative electrode main body 213, and a portion (negative electrode main body 213 and negative electrode tab 214) of the negative electrode 210 provided with the negative electrode tab 214 Smaller than the width dimension of the combined part). Therefore, when the pair of separators 215 sandwich the negative electrode 210, the negative electrode tabs 214 project from one long side (edge) of the separator 215 in the width direction. In the following, the pair of separators 215 and the portion of the negative electrode 210 sandwiched between the pair of separators 215 are referred to as a first member main body 210A, and project from one end edge in the width direction of the pair of separators 215 A portion of the negative electrode tab 214 may be referred to as a first member tab 210B (see FIG. 3).
以上の負極２１０と一対のセパレータ２１５とを有する第一部材２１（第一部材本体２１０Ａ）は、図５及び図６にも示すように、略平板状の平坦部２３１と、第一部材２１の幅方向に延びるターン軸Ｓ周りに湾曲（方向転換）しているターン部２３２とが交互に配置されることによってつづら折り状態となっている。この第一部材２１は、平行又は略平行な一対の平坦部２３１と、一対の平坦部２３１の端部同士を接続するターン部２３２と、を含む折り返し部２３を有している。詳しくは、以下の通りである。尚、図５及び図６は、折り返し部２３やつづら折り状態を説明するために、模式的に表されている。 The first member 21 (first member main body 210A) having the negative electrode 210 and the pair of separators 215 described above is, as also shown in FIG. 5 and FIG. Turn portions 232 curved (turned around) around a turn axis S extending in the width direction are alternately arranged to be in a zigzag state. The first member 21 has a folded portion 23 including a pair of parallel or substantially parallel flat portions 231 and a turn portion 232 connecting the ends of the pair of flat portions 231. The details are as follows. 5 and 6 are schematically shown in order to explain the folded portion 23 and the zigzag state.
折り返し部２３は、谷折り側の面である第一の面２３１Ａ及び山折り側の面（即ち、第一の面２３１Ａと反対側の面）である第二の面２３１Ｂをそれぞれ有し且つ第一の面２３１Ａ同士を対向させた一対の平坦部２３１と、一対の平坦部２３１の端部同士を接続するターン部２３２と、を含む。本実施形態の第一部材２１は、ターン部２３２を反対に向けた状態で隣り合う折り返し部２３（後述する第一の折り返し部２３Ａと第二の折り返し部２３Ｂ）同士がその一部（平坦部２３１）を共通させた状態で連続するつづら折り状態（蛇行状態）である。 The folded back portion 23 has a first surface 231A which is a surface on the valley folding side and a second surface 231B which is a surface on the mountain folding side (that is, a surface on the opposite side to the first surface 231A) and It includes a pair of flat portions 231 in which one surface 231A faces each other, and a turn portion 232 connecting ends of the pair of flat portions 231. In the first member 21 of this embodiment, the folded portions 23 (first folded portion 23A and second folded portion 23B described later) adjacent to each other in a state in which the turn portion 232 is opposite to each other are partially (flat portions) In the state in which the common part 231) is in common, it is a continuous zigzag state (a meandering state).
換言すると、第一部材２１は、所定の方向（第二方向：図５の上下方向）の一方側が開放されるように折り返された折り返し部（第一の折り返し部）２３Ａと、所定の方向の他方側が開放されるように折り返された折り返し部（第二の折り返し部）２３Ｂとが交互に配置されたつづら折り状態である。そして、一つの折り返し部（第一の折り返し部）２３Ａに着目したときに、第一の折り返し部２３Ａと、その隣（図５における後ろ側）の折り返し部（第二の折り返し部）２３Ｂとでは、第一の折り返し部２３Ａのターン部である第一ターン部２３２Ａと、第二の折り返し部２３Ｂのターン部である第二ターン部２３２Ｂとの間の平坦部２３１を共通させている。 In other words, the first member 21 has a folded portion (first folded portion) 23A folded so that one side in a predetermined direction (second direction: the vertical direction in FIG. 5) is opened, and the first member 21 A folded back portion (second folded back portion) 23B folded back so as to open the other side is alternately arranged in a zigzag state. Then, when focusing on one folded-back portion (first folded-back portion) 23A, the first folded-back portion 23A and the next (back side in FIG. 5) folded-back portion (second folded-back portion) 23B The flat portion 231 between the first turn portion 232A, which is the turn portion of the first folded portion 23A, and the second turn portion 232B, which is the turn portion of the second folded portion 23B, is shared.
この場合、図５に示すように、第一の折り返し部２３Ａに着目したときの平坦部２３１では、第一の折り返し部２３Ａにおける谷折り面側の面が第一の面２３１Ａであり、その反対側の面（山折り側の面）が第二の面２３１Ｂである。一方、第二の折り返し部２３Ｂに着目したときの平坦部２３１（第一の折り返し部２３Ａの平坦部２３１と共通させた平坦部）では、第二の折り返し部２３Ｂにおける谷折り面側の面が第一の面２３１Ａであり、その反対側の面（山折り側の面）が第二の面２３１Ｂである。即ち、第一の折り返し部２３Ａと第二の折り返し部２３Ｂとで共通させている平坦部２３１では、第一の折り返し部２３Ａに着目したときと、第二の折り返し部２３Ｂに着目したときとで、第一の面（折り返し部２３において向かい合う面）２３１Ａと第二の面（折り返し部２３において反対方向を向く面）２３１Ｂとが逆になる。 In this case, as shown in FIG. 5, in the flat portion 231 when focusing on the first folded portion 23A, the surface on the valley folding surface side in the first folded portion 23A is the first surface 231A, and vice versa The side surface (the surface on the mountain fold side) is the second surface 231B. On the other hand, in the flat portion 231 (flat portion common to the flat portion 231 of the first folded portion 23A) when focusing on the second folded portion 23B, the surface on the valley folding surface side in the second folded portion 23B is The first surface 231A, and the opposite surface (the surface on the mountain fold side) is the second surface 231B. That is, in the flat portion 231 common to the first folded portion 23A and the second folded portion 23B, when focusing on the first folded portion 23A and focusing on the second folded portion 23B. The first surface (surface facing in the folded portion 23) 231A and the second surface (surface facing in the opposite direction in the folded portion 23) 231B are reversed.
具体的には、図５に示すように、負極２１０において、帯状の第一部材本体２１０Ａが長尺方向において所定間隔で交互に折り返されることによって、平坦部２３１とターン部２３２とが交互に形成されている。即ち、長尺帯状の第一部材本体２１０Ａが、図４に示す長手方向に所定間隔で交互に設定された山折り線２１Ａの位置と谷折り線２１Ｂの位置とで山折りと谷折りとが交互に繰り返されることによって、つづら折り状態となる。これにより、第一部材２１（第一部材本体２１０Ａ）は、複数の平坦部２３１と複数のターン部２３２とを有し、複数の平坦部２３１のそれぞれは、平行若しくは略平行に並び、複数のターン部２３２（第一ターン部２３２Ａ、第二ターン部２３２Ｂ）のそれぞれは、隣り合う平坦部２３１の前記長尺方向の一端側の端部同士と他端側の端部同士とを交互に接続している。本実施形態の平坦部２３１は、Ｙ軸方向に長い矩形状である。 More specifically, as shown in FIG. 5, the flat portion 231 and the turn portion 232 are alternately formed by alternately folding back the strip-shaped first member main body 210A at a predetermined interval in the longitudinal direction in the negative electrode 210. It is done. That is, mountain folds and valley folds occur at the position of the mountain fold line 21A and the position of the valley fold line 21B where the long strip-shaped first member main body 210A is alternately set at predetermined intervals in the longitudinal direction shown in FIG. By alternately repeating, it becomes a zigzag state. Thereby, the first member 21 (first member main body 210A) has a plurality of flat portions 231 and a plurality of turn portions 232, and each of the plurality of flat portions 231 is arranged in parallel or substantially in parallel. Each of the turn portions 232 (first turn portion 232A, second turn portion 232B) alternately connects the end portions on one end side and the end portions on the other end side of the flat portions 231 adjacent to each other in the longitudinal direction. doing. The flat portion 231 of the present embodiment is a rectangular shape that is long in the Y-axis direction.
以下では、平坦部２３１が並ぶ方向を直交座標系におけるＸ軸方向とし、ターン部２３２のターン軸Ｓの延びる方向（第一方向：図５参照）を直交座標系のＹ軸方向とし、平坦部２３１に対してターン部２３２が配置されている方向（第二方向：図５における上下方向）を直交座標系におけるＺ軸方向とする。 In the following, the direction in which the flat portions 231 are arranged is taken as the X axis direction in the orthogonal coordinate system, and the direction in which the turn axis S of the turn portion 232 extends (first direction: see FIG. 5) is taken as the Y axis direction in the orthogonal coordinate system. The direction in which the turn portion 232 is arranged with respect to 231 (second direction: the vertical direction in FIG. 5) is taken as the Z-axis direction in the orthogonal coordinate system.
第一部材２１において、各平坦部２３１から延びる第一部材タブ２１０Ｂ（負極タブ２１４におけるセパレータ２１５から突出している部位）は、Ｘ軸方向から見て重なっている。この複数の平坦部２３１のそれぞれから延びている第一部材タブ２１０Ｂは、束ねられた状態でクリップ部材６に挟み込まれる。このクリップ部材６が集電体５に接続されることで、第一部材タブ２１０Ｂの束は、クリップ部材６及び集電体５を介して外部端子４と接続される。 In the first member 21, the first member tabs 210 </ b> B (portions of the negative electrode tab 214 protruding from the separator 215) extending from the flat portions 231 overlap when viewed from the X-axis direction. The first member tabs 210B extending from each of the plurality of flat portions 231 are clipped by the clip member 6 in a bundled state. By connecting the clip member 6 to the current collector 5, the bundle of first member tabs 210 B is connected to the external terminal 4 via the clip member 6 and the current collector 5.
複数のターン部２３２のそれぞれは、つづら折り状態の第一部材２１において、Ｙ軸方向に延びる軸をターン軸Ｓ（図５及び図６参照）として帯状の第一部材本体２１０Ａが旋回（方向転換）している（換言すると、ターン軸Ｓ周りに湾曲している）部位である。 In each of the plurality of turn parts 232, in the first member 21 in a zigzag state, the strip-like first member main body 210A is turned (turned) with the axis extending in the Y axis direction as the turn axis S (see FIGS. 5 and 6). (In other words, curved around the turn axis S).
以上のように構成される第一部材２１では、第一部材２１を構成する負極２１０と一対のセパレータ２１５とのそれぞれも、互いに重ねられた状態でつづら折り状態に折り畳まれている。具体的には、以下の通りである。 In the first member 21 configured as described above, each of the negative electrode 210 and the pair of separators 215 that constitute the first member 21 is also folded in a zigzag state in a state in which the negative electrode 210 and the pair of separators 215 overlap each other. Specifically, it is as follows.
長尺な負極２１０において、第一部材２１の第一の折り返し部２３Ａと対応する部位が負極２１０の第一の折り返し部であり、第一部材２１の第二の折り返し部２３Ｂと対応する部位が負極２１０の第二の折り返し部である。また、負極２１０の各折り返し部において、第一部材２１の平坦部２３１に対応する部位が負極２１０の平坦部であり、第一部材２１のターン部２３２に対応する部位が負極２１０のターン部である。 In the elongated negative electrode 210, the portion corresponding to the first folded portion 23A of the first member 21 is the first folded portion of the negative electrode 210, and the portion corresponding to the second folded portion 23B of the first member 21 is This is a second folded portion of the negative electrode 210. Further, in each folded portion of the negative electrode 210, the portion corresponding to the flat portion 231 of the first member 21 is the flat portion of the negative electrode 210, and the portion corresponding to the turn portion 232 of the first member 21 is the turn portion of the negative electrode 210. is there.
同様に、長尺な各セパレータ２１５において、第一部材２１の第一の折り返し部２３Ａと対応する部位がセパレータ２１５の第一の折り返し部であり、第一部材２１の第二の折り返し部２３Ｂと対応する部位がセパレータ２１５の第二の折り返し部である。また、セパレータ２１５の各折り返し部において、第一部材２１の平坦部２３１に対応する部位がセパレータ２１５の平坦部であり、第一部材２１のターン部２３２に対応する部位がセパレータ２１５のターン部である。 Similarly, in each elongated separator 215, the portion corresponding to the first folded portion 23A of the first member 21 is the first folded portion of the separator 215, and the second folded portion 23B of the first member 21 and The corresponding portion is the second folded portion of the separator 215. In each of the folded portions of the separator 215, the portion corresponding to the flat portion 231 of the first member 21 is the flat portion of the separator 215, and the portion corresponding to the turn portion 232 of the first member 21 is the turn portion of the separator 215. is there.
これら負極２１０の各平坦部とセパレータ２１５の各平坦部とは、それぞれ平行又は略平行であり、負極２１０の各ターン部又はセパレータ２１５の各ターン部は、それぞれターン軸Ｓ周りで方向転換するように負極２１０の平坦部同士を接続し又はセパレータ２１５の平坦部同士を接続している。 Each flat portion of the negative electrode 210 and each flat portion of the separator 215 are parallel or substantially parallel, and each turn of the negative electrode 210 or each turn of the separator 215 is turned around the turn axis S. The flat portions of the negative electrode 210 are connected to each other, or the flat portions of the separator 215 are connected to each other.
第二部材２２（本実施形態の例では正極２２０）は、図３に示すように、少なくとも一部をＹ軸方向に突出させた状態で、折り返し部２３の内側（詳しくは、折り返し部２３を構成する一対の平坦部２３１の間）に配置される。 As shown in FIG. 3, the second member 22 (in the example of the present embodiment, the positive electrode 220) is an inner side of the folded portion 23 (specifically, the folded portion 23) in a state in which at least a portion is protruded in the Y axis direction. It arrange | positions between a pair of flat parts 231 to comprise).
複数の正極２２０（第二部材２２）のそれぞれは、第一部材２１のＹ軸方向の他方側（図３における右側）の端縁から突出している部位から延び且つＹ軸方向から見て前記端縁（セパレータ２１５の端縁）と重なる部位を有する延出部２２６を有する。具体的に、複数の正極２２０のそれぞれは、一対の平坦部２３１の間に配置されると共に、Ｙ軸方向における折り返し部２３の他方側の端縁より他方側においてターン部２３２よりＺ軸方向の外側に突出するように延びる延出部２２６を有する。詳しくは、以下の通りである。 Each of the plurality of positive electrodes 220 (second member 22) extends from a portion protruding from the end edge of the other side (right side in FIG. 3) of the first member 21 in the Y-axis direction, and viewed from the Y-axis direction It has the extension part 226 which has a site | part which overlaps with an edge (edge of the separator 215). Specifically, each of the plurality of positive electrodes 220 is disposed between the pair of flat portions 231, and on the other side of the other end of the folded-back portion 23 in the Y-axis direction, in the Z-axis direction It has the extension part 226 extended so that it may protrude outside. The details are as follows.
正極２２０は、図３及び図７にも示すように、金属箔２２１と、金属箔２２１の両面のそれぞれに重ねられる正極活物質層２２２と、を有する。即ち、正極２２０は、一つの金属箔２２１と一対の正極活物質層２２２とを有する。また、正極２２０は、金属箔２２１に重ねられるコート層２２９も有する。本実施形態の金属箔２２１は、例えば、アルミニウム箔である。この正極２２０は、つづら折り状態の第一部材２１において、各折り返し部２３の一対の平坦部２３１間のそれぞれに配置されている。このため、本実施形態の電極体２は、複数（第一部材２１の折り返し部２３の数に対応する数）の正極２２０（第二部材２２）を有している。 As shown in FIGS. 3 and 7, the positive electrode 220 has a metal foil 221 and a positive electrode active material layer 222 superimposed on each of both sides of the metal foil 221. That is, the positive electrode 220 has one metal foil 221 and a pair of positive electrode active material layers 222. In addition, the positive electrode 220 also has a coat layer 229 which is superimposed on the metal foil 221. The metal foil 221 of the present embodiment is, for example, an aluminum foil. The positive electrode 220 is disposed between the pair of flat portions 231 of each folded portion 23 in the first member 21 in a zigzag state. For this reason, the electrode body 2 of the present embodiment has a plurality (a number corresponding to the number of the folding parts 23 of the first member 21) of the positive electrodes 220 (the second member 22).
正極活物質層２２２は、正極活物質と、バインダーと、を有する。 The positive electrode active material layer 222 includes a positive electrode active material and a binder.
本実施形態の正極活物質は、例えば、リチウム金属酸化物である。具体的に、正極活物質は、例えば、ＬｉａＭｅｂＯｃ（Ｍｅは、１又は２以上の遷移金属を表す）によって表される複合酸化物（ＬｉａＣｏｙＯ２、ＬｉａＮｉｘＯ２、ＬｉａＭｎｚＯ４、ＬｉａＮｉｘＣｏｙＭｎｚＯ２等）、ＬｉａＭｅｂ（ＸＯｃ）ｄ（Ｍｅは、１又は２以上の遷移金属を表し、Ｘは例えばＰ、Ｓｉ、Ｂ、Ｖを表す）によって表されるポリアニオン化合物（ＬｉａＦｅｂＰＯ４、ＬｉａＭｎｂＰＯ４、ＬｉａＭｎｂＳｉＯ４、ＬｉａＣｏｂＰＯ４Ｆ等）である。本実施形態の正極活物質は、ＬｉＮｉ１／３Ｃｏ１／３Ｍｎ１／３Ｏ２である。 The positive electrode active material of the present embodiment is, for example, a lithium metal oxide. Specifically, the positive electrode active material is, for example, a composite oxide represented by LiaMebOc (Me represents one or more transition metals) (LiaCoyO 2 , LiaNixO 2 , LiaMnzO 4 , LiaNixCoyMnzO 2 etc.), LiaMeb XOc) d (Me represents one or more transition metals, and X represents, for example, P, Si, B, V). Polyanion compound (LiaFebPO 4 , LiaMnbPO 4 , LiaMnbSiO 4 , LiaCobPO 4 F, etc.) ). The positive electrode active material of the present embodiment is LiNi 1/3 Co 1/3 Mn 1/3 O 2 .
正極活物質層２２２に用いられるバインダーは、負極活物質層２１２に用いられたバインダーと同様のものである。本実施形態のバインダーは、ポリフッ化ビニリデンである。 The binder used for the positive electrode active material layer 222 is the same as the binder used for the negative electrode active material layer 212. The binder of the present embodiment is polyvinylidene fluoride.
正極活物質層２２２は、ケッチェンブラック（登録商標）、アセチレンブラック、黒鉛等の導電助剤をさらに有してもよい。本実施形態の正極活物質層２２２は、導電助剤としてアセチレンブラックを有する。 The positive electrode active material layer 222 may further have a conductive aid such as ketjen black (registered trademark), acetylene black, or graphite. The positive electrode active material layer 222 of the present embodiment has acetylene black as a conductive additive.
具体的に、複数の正極２２０のそれぞれは、矩形状の正極本体（正極活物質層形成部（活物質層形成部））２２３と、正極本体２２３の矩形状の輪郭を構成する一辺と連接する（本実施形態の例では、Ｙ軸方向の端縁からＹ軸方向に延びる）正極タブ（正極活物質層非形成部（活物質層非形成部））２２４と、を有する。これら正極本体２２３と正極タブ２２４とは、Ｙ軸方向（第一方向）に並んでいる。また、複数の正極２２０のそれぞれは、少なくとも正極タブ２２４に重ねられるコート層２２９も有する。 Specifically, each of the plurality of positive electrodes 220 is connected to a rectangular positive electrode main body (positive electrode active material layer forming portion (active material layer forming portion)) 223 and one side forming a rectangular outline of the positive electrode main body 223 (In the example of the present embodiment, a positive electrode tab (positive electrode active material layer non-forming portion (active material layer non-forming portion)) 224 (extending in the Y-axis direction from an edge in the Y-axis direction). The positive electrode body 223 and the positive electrode tab 224 are arranged in the Y-axis direction (first direction). Each of the plurality of positive electrodes 220 also has a coat layer 229 superimposed on at least the positive electrode tab 224.
本実施形態の正極本体２２３は、Ｙ軸方向に長い矩形状である。この正極本体２２３では、金属箔２２１と正極活物質層２２２とが重ねられている。具体的に、正極本体２２３は、矩形の金属箔２２１と、金属箔２２１の両面の全域に重ねられる正極活物質層２２２と、を有する。正極本体２２３における正極活物質層２２２は、Ｘ軸方向に対向する（詳しくは、セパレータ２１５を介して対向する）平坦部２３１の負極活物質層２１２よりＹ−Ｚ面（Ｙ軸とＺ軸とを含む面）方向において小さい。これにより、正極本体２２３の正極活物質層２２２は、全域において平坦部２３１の負極活物質層２１２と対向している。 The positive electrode body 223 of the present embodiment has a rectangular shape elongated in the Y-axis direction. In the positive electrode main body 223, the metal foil 221 and the positive electrode active material layer 222 are stacked. Specifically, the positive electrode main body 223 has a rectangular metal foil 221 and a positive electrode active material layer 222 which is superimposed on the entire area of both surfaces of the metal foil 221. The positive electrode active material layer 222 in the positive electrode main body 223 has a YZ plane (Y axis and Z axis) from the negative electrode active material layer 212 of the flat portion 231 facing in the X axis direction (specifically, facing via the separator 215). Small in the direction including the Thus, the positive electrode active material layer 222 of the positive electrode main body 223 faces the negative electrode active material layer 212 of the flat portion 231 in the entire area.
正極タブ２２４は、正極本体２２３から延びるタブ本体２２５と、タブ本体２２５からＺ軸方向へ延びる延出部２２６と、を有する。この正極タブ２２４は、金属箔２２１と、金属箔２２１に重ねられるコート層２２９と、によって形成されている。即ち、正極タブ２２４は、正極活物質層２２２を重ねられていない。 The positive electrode tab 224 has a tab main body 225 extending from the positive electrode main body 223 and an extending portion 226 extending from the tab main body 225 in the Z-axis direction. The positive electrode tab 224 is formed of a metal foil 221 and a coat layer 229 overlaid on the metal foil 221. That is, the positive electrode tab 224 is not overlapped with the positive electrode active material layer 222.
タブ本体２２５は、正極本体２２３のＹ軸方向の他方側（図７の右側）の端縁からＹ軸方向に延びる部位である。このタブ本体２２５における延出部２２６の設けられたＺ軸方向の端部と反対側の端部に、延出部２２６に対応する形状の切り欠き２２５１が形成されている。本実施形態の切り欠き２２５１は、Ｙ軸方向に長尺な矩形である。 The tab main body 225 is a portion extending in the Y-axis direction from the edge of the other side (right side in FIG. 7) of the positive electrode main body 223 in the Y-axis direction. A notch 2251 having a shape corresponding to the extending portion 226 is formed at an end of the tab main body 225 opposite to the end in the Z-axis direction where the extending portion 226 is provided. The notch 2251 in the present embodiment is a rectangular elongated in the Y-axis direction.
延出部２２６は、タブ本体２２５のＺ軸方向の端部（切り欠き２２５１の設けられる端部と反対側の端部）からＺ軸方向に延びている（突出している）。この延出部２２６におけるＹ軸方向の正極本体２２３側の端縁２２６Ａは、タブ本体２２５のＺ軸方向の端縁における所定位置（正極本体２２３とタブ本体２２５との境界位置ｂ１からＹ軸方向に間隔をあけた位置）からＺ軸方向に延びている。これにより、正極タブ２２４の端縁は、タブ本体２２５のＺ軸方向の端縁２２５Ａと延出部２２６の端縁２２６Ａとの境界位置ｂ２において、曲がっている。本実施形態の前記境界位置ｂ２での正極タブ２２４の端縁は、９０°となるように屈曲している。本実施形態の延出部２２６は、Ｙ軸方向に長尺な矩形である。 The extension portion 226 extends (projects) in the Z-axis direction from the end in the Z-axis direction of the tab main body 225 (the end opposite to the end where the notch 2251 is provided). An end 226A of the extension 226 on the side of the positive electrode main body 223 in the Y-axis direction is a predetermined position at an end of the tab main body 225 in the Z-axis direction (from the boundary position b1 between the positive electrode main body 223 and the tab main body 225 And extends in the Z-axis direction. Thus, the edge of the positive electrode tab 224 is bent at a boundary position b2 between the edge 225A in the Z-axis direction of the tab body 225 and the edge 226A of the extension 226. The edge of the positive electrode tab 224 at the boundary position b2 of this embodiment is bent to be 90 °. The extension part 226 of the present embodiment is a rectangle elongated in the Y-axis direction.
本実施形態の電極体２では、第一の折り返し部２３Ａの内側に配置される正極２２０の延出部２２６は、第一ターン部２３２ＡからＺ軸方向の他方側（第一の折り返し部２３Ａが開放されている側と反対側：図３における下側）に突出し、第二の折り返し部２３Ｂの内側に配置される正極２２０の延出部２２６は、第二ターン部２３２ＢからＺ軸方向の一方側（第二の折り返し部２３Ｂが開放されている側と反対側：図３における上側）に突出する。 In the electrode body 2 of the present embodiment, the extension part 226 of the positive electrode 220 disposed inside the first folded part 23A is the other side in the Z-axis direction from the first turn part 232A (the first folded part 23A is The side opposite to the open side: the extending portion 226 of the positive electrode 220 which protrudes to the lower side in FIG. 3 and is disposed inside the second folded portion 23B is one side in the Z-axis direction from the second turn portion 232B. It projects on the side (the side opposite to the side where the second folded portion 23B is open: the upper side in FIG. 3).
コート層２２９は、絶縁性を有する。このコート層２２９は、例えば、絶縁性粒子とバインダーとを含む層、テープ、フィルムによって形成されている。コート層２２９は、バインダーのみからなる層であってもよい。絶縁性粒子には、例えば、アルミナ、シリカ、アルミノケイ酸塩が用いられる。バインダーには、例えば、負極活物質層２１２に用いられたバインダーと同様のものが用いられる。テープ又はフィルムは、例えば、ポリエチレン、ポリプロピレン、ポリフェニレンサルファイド製のものが用いられる。コート層２２９は、正極タブ２２４におけるタブ本体２２５の端縁２２５Ａと延出部２２６の端縁２２６Ａとの境界位置ｂ２（正極タブ２２４の端縁における屈曲している位置）を含む領域において金属箔２２１に重ねられている。具体的に、コート層２２９は、Ｙ軸方向において、正極本体２２３と正極タブ２２４との境界位置ｂ１から、延出部２２６の端縁２２６Ａを越えた位置まで、正極タブ２２４を覆っている。本実施形態のコート層２２９は、正極タブ２２４の両面のそれぞれに配置されている。即ち、正極２２０は、一対のコート層２２９を有する。 The coat layer 229 has insulation. The coat layer 229 is formed of, for example, a layer including insulating particles and a binder, a tape, and a film. The coat layer 229 may be a layer consisting only of a binder. For the insulating particles, for example, alumina, silica, and aluminosilicate are used. As the binder, for example, the same one as the binder used for the negative electrode active material layer 212 is used. As the tape or film, for example, one made of polyethylene, polypropylene or polyphenylene sulfide is used. The coat layer 229 is a metal foil in a region including a boundary position b2 (a bent position at the edge of the positive electrode tab 224) of the edge 225A of the tab main body 225 at the positive electrode tab 224 and the edge 226A of the extending portion 226. It is superimposed on 221. Specifically, the coat layer 229 covers the positive electrode tab 224 from the boundary position b1 of the positive electrode body 223 and the positive electrode tab 224 in the Y-axis direction to a position beyond the end edge 226A of the extending portion 226. The coat layer 229 in the present embodiment is disposed on each of both sides of the positive electrode tab 224. That is, the positive electrode 220 has a pair of coat layers 229.
電極体２において、各正極２２０の正極タブ２２４は、Ｘ軸方向から見て重なっている。詳しくは、各第一の折り返し部２３Ａの内側に配置される正極２２０の正極タブ２２４のそれぞれは、Ｘ軸方向から見て一致又は略一致するように重なり、各第二の折り返し部２３Ｂの内側に配置される正極２２０の正極タブ２２４のそれぞれは、Ｘ軸方向から見て一致又は略一致するように重なる。そして、第一の折り返し部２３Ａの内側に配置される正極２２０の正極タブ２２４と、第二の折り返し部２３Ｂの内側に配置される正極２２０の正極タブ２２４とでは、タブ本体２２５の延出部２２６側の端部と延出部２２６とを除いた部位（タブ本体２２５のＺ軸方向の一部）がＸ軸方向から見て重なっている。この複数の正極２２０のそれぞれの正極タブ２２４は、束ねられ、クリップ部材６に挟み込まれる。このクリップ部材６が集電体５に接続されることで、正極タブ２２４の束は、クリップ部材６及び集電体５を介して外部端子４と接続される。 In the electrode body 2, the positive electrode tabs 224 of the respective positive electrodes 220 overlap when viewed from the X-axis direction. Specifically, each of the positive electrode tabs 224 of the positive electrode 220 disposed on the inner side of each first folded portion 23A overlaps so as to match or substantially match when viewed from the X-axis direction, and the inner side of each second folded portion 23B Each of the positive electrode tabs 224 of the positive electrode 220 disposed at the top and bottom of the positive electrode 220 overlap so as to match or substantially match when viewed from the X-axis direction. In the positive electrode tab 224 of the positive electrode 220 disposed inside the first folded portion 23A and the positive electrode tab 224 of the positive electrode 220 disposed inside the second folded portion 23B, the extension portion of the tab main body 225 A portion (a part in the Z-axis direction of the tab main body 225) excluding the end portion on the 226 side and the extension portion 226 overlaps as seen from the X-axis direction. The respective positive electrode tabs 224 of the plurality of positive electrodes 220 are bundled and sandwiched by the clip member 6. By connecting the clip member 6 to the current collector 5, the bundle of positive electrode tabs 224 is connected to the external terminal 4 via the clip member 6 and the current collector 5.
以上の正極２２０は、次のように製造される。長尺帯状の金属箔２２１の両面に、幅方向（短手方向）の一方側（図８の例では上側）の端部を残して正極活物質層２２２とコート層２２９とが重ねられる。そして、この金属箔２２１の両面に正極活物質層２２２とコート層２２９とが重ねられた帯状の部材が、長手方向に等間隔となるように設定された所定の切断予定線αに沿って切断される。これにより、正極２２０が形成される。 The above positive electrode 220 is manufactured as follows. The positive electrode active material layer 222 and the coat layer 229 are superimposed on both sides of the long strip-shaped metal foil 221 leaving an end on one side (upper side in the example of FIG. 8) in the width direction (short side direction). Then, a strip-shaped member in which the positive electrode active material layer 222 and the coating layer 229 are superimposed on both surfaces of the metal foil 221 is cut along a predetermined planned cutting line α set so as to be equally spaced in the longitudinal direction. Be done. Thereby, the positive electrode 220 is formed.
この切断予定線αは、幅方向の一方側（図８の下側）の端縁からコート層２２９の中央部まで幅方向に真っ直ぐ延びる第一部位α１と、第一部位α１の先端から長手方向に延びる第二部位α２と、第二部位α２の先端から幅方向の他方側（図８の上側）の端縁に向けて幅方向に延びる第三部位α３と、によって構成されている。第二部位α２の長さは、延出部２２６の突出方向の長さに相当する。 The planned cutting line α is a first portion α1 extending straight in the width direction from the edge on one side in the width direction (the lower side in FIG. 8) to the central portion of the coating layer 229, and a longitudinal direction from the tip of the first portion α1. And a third portion α3 extending in the width direction from the tip of the second portion α2 toward the other end (upper side in FIG. 8) of the width direction. The length of the second portion α2 corresponds to the length of the extension portion 226 in the protrusion direction.
図１及び図２に戻り、ケース３は、開口を有するケース本体３１と、ケース本体３１の開口を塞ぐ（閉じる）蓋板３２と、を有する。このケース３では、ケース本体３１と蓋板３２とによって内部空間が画定される。ケース３は、この内部空間に、電極体２と共に電解液を収容する。 Referring back to FIGS. 1 and 2, the case 3 has a case main body 31 having an opening, and a lid plate 32 that closes (closes) the opening of the case main body 31. In the case 3, an inner space is defined by the case body 31 and the cover plate 32. The case 3 accommodates the electrolytic solution together with the electrode assembly 2 in the internal space.
この電解液は、非水溶液系電解液である。この電解液は、有機溶媒に電解質塩を溶解させることによって得られる。有機溶媒は、例えば、プロピレンカーボネート及びエチレンカーボネートなどの環状炭酸エステル類、ジメチルカーボネート、ジエチルカーボネート、及びエチルメチルカーボネートなどの鎖状カーボネート類である。電解質塩は、ＬｉＣｌＯ４、ＬｉＢＦ４、及びＬｉＰＦ６等である。本実施形態の電解液は、エチレンカーボネート、ジメチルカーボネート、及びエチルメチルカーボネートを、エチレンカーボネート：ジメチルカーボネート：エチルメチルカーボネート＝３：２：５の割合で調整した混合溶媒に、１ｍｏｌ／ＬのＬｉＰＦ６を溶解させたものである。 This electrolyte is a non-aqueous electrolyte. This electrolytic solution is obtained by dissolving an electrolyte salt in an organic solvent. The organic solvent is, for example, cyclic carbonates such as propylene carbonate and ethylene carbonate, linear carbonates such as dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate. The electrolyte salt is LiClO 4 , LiBF 4 , LiPF 6 or the like. The electrolyte solution of the present embodiment is prepared by mixing ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate in a mixed solvent prepared by adjusting the ratio of ethylene carbonate: dimethyl carbonate: ethyl methyl carbonate = 3: 2: 5 to 1 mol / L of LiPF 6 Was dissolved.
ケース３は、上記の電解液に耐性を有する金属によって形成される。本実施形態のケース３は、例えば、アルミニウム、又は、アルミニウム合金等のアルミニウム系金属材料によって形成される。 Case 3 is formed of a metal resistant to the above-described electrolyte solution. The case 3 of the present embodiment is formed of, for example, an aluminum-based metal material such as aluminum or an aluminum alloy.
ケース本体３１は、板状の閉塞部３１１と、閉塞部３１１の周縁に接続される筒状の胴部（周壁）３１２と、を備える。 The case main body 31 includes a plate-like closing portion 311 and a cylindrical trunk portion (peripheral wall) 312 connected to the peripheral edge of the closing portion 311.
閉塞部３１１は、ケース本体３１が開口を上に向けた姿勢で配置されたときにケース本体３１の下端に位置する（即ち、前記開口が上を向いたときのケース本体３１の底壁部となる）部位である。本実施形態の閉塞部３１１は、矩形状である。 The closing portion 311 is positioned at the lower end of the case body 31 when the case body 31 is disposed in the posture in which the opening is directed upward (that is, the bottom wall portion of the case body 31 when the opening faces upward) ) Site. The closed portion 311 of the present embodiment is rectangular.
胴部３１２は、角筒形状、より詳しくは、偏平な角筒形状を有する。胴部３１２は、閉塞部３１１の周縁における長辺から延びる一対の長壁部３１３と、閉塞部３１１の周縁における短辺から延びる一対の短壁部３１４とを有する。短壁部３１４が一対の長壁部３１３の対応（詳しくは、Ｘ軸方向に対向）する端部同士をそれぞれ接続することによって、角筒状の胴部３１２が形成される。 The body portion 312 has a square tube shape, more specifically, a flat square tube shape. The body portion 312 has a pair of long wall portions 313 extending from the long side in the peripheral edge of the closing portion 311 and a pair of short wall portions 314 extending from the short side in the peripheral edge of the closing portion 311. By connecting the short wall portions 314 to the corresponding end portions of the pair of long wall portions 313 (specifically, facing in the X-axis direction), the rectangular cylindrical body portion 312 is formed.
以上のように、ケース本体３１は、開口方向（Ｚ軸方向）における一方の端部が塞がれた角筒形状（即ち、有底角筒形状）を有する。 As described above, the case main body 31 has a rectangular tube shape (that is, a bottomed rectangular tube shape) in which one end in the opening direction (Z-axis direction) is closed.
蓋板３２は、ケース本体３１の開口を塞ぐ部材である。この蓋板３２の輪郭形状は、ケース本体３１の開口周縁部３１０（図２参照）に対応した形状である。即ち、蓋板３２は、Ｙ軸方向に長い矩形状の板材である。 The lid plate 32 is a member that closes the opening of the case main body 31. The outline shape of the lid plate 32 is a shape corresponding to the opening peripheral edge portion 310 (see FIG. 2) of the case main body 31. That is, the cover plate 32 is a rectangular plate material long in the Y-axis direction.
以上のように構成されるケース３には、各第一部材２１の平坦部２３１のそれぞれが長壁部３１３と平行（略平行）となり、各ターン部２３２が閉塞部３１１又は蓋板３２と対向するように、絶縁部材７に覆われた状態の電極体２が収容される。このとき、各折り返し部２３の内側には正極２２０が配置され、ケース３は電極体２の全体をＸ軸方向に圧迫（押圧）した状態で該電極体２を収容する。 In the case 3 configured as described above, each flat portion 231 of each first member 21 is parallel (substantially parallel) to the long wall portion 313, and each turn portion 232 faces the closing portion 311 or the lid plate 32. Thus, the electrode body 2 in the state of being covered by the insulating member 7 is accommodated. At this time, the positive electrode 220 is disposed inside each folded portion 23, and the case 3 accommodates the electrode assembly 2 in a state where the entire electrode assembly 2 is pressed (pressed) in the X-axis direction.
外部端子４は、他の蓄電素子の外部端子又は外部機器等と電気的に接続される部位である。このため、外部端子４は、導電性を有する部材によって形成される。また、外部端子４は、溶接性の高い金属材料によって形成される。例えば、正極の外部端子４は、アルミニウム又はアルミニウム合金等のアルミニウム系金属材料によって形成され、負極の外部端子４は、銅又は銅合金等の銅系金属材料によって形成される。本実施形態の外部端子４は、少なくとも一部がケース３の外部に露出した状態で蓋板３２に取り付けられる。 The external terminal 4 is a portion electrically connected to an external terminal of another storage element or an external device. Thus, the external terminal 4 is formed of a conductive member. Further, the external terminal 4 is formed of a metal material having high weldability. For example, the external terminal 4 of the positive electrode is formed of an aluminum-based metal material such as aluminum or an aluminum alloy, and the external terminal 4 of the negative electrode is formed of a copper-based metal material such as copper or a copper alloy. The external terminal 4 of the present embodiment is attached to the cover plate 32 in a state where at least a part is exposed to the outside of the case 3.
集電体５は、導電性を有する部材によって形成され、電極体２と外部端子４とを通電させる。具体的に、集電体５は、外部端子４に接続される第一接続部５１と、電極体２に接続される第二接続部５２と、を有する。本実施形態の第二接続部５２は、クリップ部材６を介して電極体２に接続される。 The current collector 5 is formed of a conductive member, and causes the electrode body 2 and the external terminal 4 to be energized. Specifically, the current collector 5 has a first connection portion 51 connected to the external terminal 4 and a second connection portion 52 connected to the electrode body 2. The second connection portion 52 of the present embodiment is connected to the electrode body 2 via the clip member 6.
第一接続部５１は、外部端子４から蓋板３２に沿って短壁部３１４に向けて延びる板状の部位である。第二接続部５２は、第一接続部５１の短壁部３１４側の端部（詳しくは、該端部のＸ軸方向の両側）から、長壁部３１３に沿い且つ閉塞部３１１に向けて延びる板状の部位である。この第二接続部５２は、例えば、超音波接合によって、電極体２（詳しくは、クリップ部材６に挟み込まれた状態の第一部材タブ２１０Ｂ又は正極タブ２２４の束）に接合される。 The first connection portion 51 is a plate-like portion extending from the external terminal 4 along the cover plate 32 toward the short wall portion 314. The second connection portion 52 extends along the long wall portion 313 and toward the closing portion 311 from the end on the short wall portion 314 side of the first connection portion 51 (specifically, both sides in the X-axis direction of the end). It is a plate-like part. The second connection portion 52 is bonded to the electrode body 2 (specifically, the bundle of the first member tab 210B or the positive electrode tab 224 in a state of being sandwiched between the clip members 6) by ultrasonic bonding, for example.
以上のように構成される集電体５は、蓄電素子１の正極と負極とにそれぞれ配置される（図２参照）。本実施形態の蓄電素子１では、ケース３内において、電極体２の第一部材タブ２１０Ｂの束と、正極タブ２２４の束とに対応する位置にそれぞれ配置される。正極の集電体５と負極の集電体５とは、異なる素材によって形成される。具体的に、正極の集電体５は、例えば、アルミニウム又はアルミニウム合金によって形成され、負極の集電体５は、例えば、銅又は銅合金によって形成される。 The current collectors 5 configured as described above are respectively disposed on the positive electrode and the negative electrode of the storage element 1 (see FIG. 2). In the storage element 1 of the present embodiment, in the case 3, the storage element 1 is disposed at a position corresponding to the bundle of the first member tabs 210 B of the electrode body 2 and the bundle of the positive electrode tabs 224. The current collector 5 of the positive electrode and the current collector 5 of the negative electrode are formed of different materials. Specifically, the current collector 5 of the positive electrode is formed of, for example, aluminum or an aluminum alloy, and the current collector 5 of the negative electrode is formed of, for example, copper or a copper alloy.
クリップ部材６は、導電性を有し、電極体２のＹ軸方向の端部（具体的には、第一部材タブ２１０Ｂの束、又は正極タブ２２４の束）を挟み込む。本実施形態のクリップ部材６は、第一部材タブ２１０Ｂの束、又は正極タブ２２４の束を挟み込んだ状態で、超音波接合によって集電体５（詳しくは、第二接続部５２）に接続される。このクリップ部材６は、板状の金属部材が曲げ加工されることによって形成される。 The clip member 6 has conductivity, and sandwiches the end of the electrode body 2 in the Y-axis direction (specifically, the bundle of the first member tabs 210B or the bundle of the positive electrode tabs 224). The clip member 6 of the present embodiment is connected to the current collector 5 (specifically, the second connection portion 52) by ultrasonic bonding in a state in which the bundle of first member tabs 210B or the bundle of positive electrode tabs 224 is sandwiched. Ru. The clip member 6 is formed by bending a plate-like metal member.
絶縁部材７は、絶縁性を有する樹脂によって形成されている。具体的に、絶縁部材７は、所定の形状に裁断された絶縁性を有するシート状の部材を折り曲げることによって袋状に形成されている（図２参照）。本実施形態の絶縁部材７は、ケース３に沿った形の袋状である。 The insulating member 7 is formed of an insulating resin. Specifically, the insulating member 7 is formed in a bag shape by bending a sheet-like member having insulation that is cut into a predetermined shape (see FIG. 2). The insulating member 7 of the present embodiment is shaped like a bag along the case 3.
以上の蓄電素子１によれば、正極タブ（活物質層非形成部）２２４がセパレータ２１５側（正極本体２２３側：図３における左側）に向かう向きに正極２２０が移動し又は移動しようとしたときに、延出部２２６がセパレータ２１５のＹ軸方向の端縁に当接し又は当接していることで、それ以上のセパレータ２１５側への正極２２０の移動が規制される。これにより、セパレータ２１５を介して隣り合う電極（負極２１０と正極２２０と）の一方の電極２１０、２２０の活物質層形成部２１３、２２３（活物質層のある部位）と他方の電極２２０、２１０の活物質層非形成部２２４、２１４（活物質層のない部位）とが対向し難くなる。その結果、前記隣り合う電極２１０、２２０の間に配置されたセパレータ２１５がずれ又は損傷等しても、前記一方の電極２１０、２２０の活物質層非形成部２１４、２２４と前記他方の電極２２０、２１０の活物質層形成部２２３、２１３との間での短絡の発生が抑えられる。 According to the storage element 1 described above, when the positive electrode 220 moves in the direction toward the positive electrode tab (active material layer non-forming portion) 224 toward the separator 215 side (positive electrode main body 223 side: left side in FIG. 3) In addition, the extension part 226 abuts or abuts on the end edge of the separator 215 in the Y-axis direction, thereby restricting the movement of the positive electrode 220 further to the separator 215 side. Thus, the active material layer forming portions 213 and 223 (portions having an active material layer) of one of the electrodes 210 and 220 adjacent to each other (the negative electrode 210 and the positive electrode 220) with the separator 215 interposed therebetween and the other electrodes 220 and 210 It becomes difficult for the active material layer non-forming portions 224 and 214 (portions without active material layer) to face each other. As a result, even if the separator 215 disposed between the adjacent electrodes 210 and 220 shifts or is damaged, the active material layer non-forming portions 214 and 224 of the one electrode 210 and the other electrode 220 The occurrence of a short circuit between the active material layer forming portions 223 and 213 can be suppressed.
本実施形態の正極２２０では、正極タブ２２４が、タブ本体２２５の端縁２２５Ａと延出部２２６の端縁２２６Ａとの境界位置（正極タブ２２４の端縁における屈曲している位置）ｂ２を含む領域において金属箔２２１に重ねられたコート層２２９を有している。これにより、正極タブ２２４において、延出部２２６がセパレータ２１５の端縁に当接した状態で正極２２０がセパレータ２１５側に移動しようとしたときに応力が集中し易い部位（正極タブ２２４の端縁において屈曲している部位）からの裂けが抑えられる。 In the positive electrode 220 of the present embodiment, the positive electrode tab 224 includes a boundary position (a bent position at the edge of the positive electrode tab 224) b2 between the edge 225A of the tab body 225 and the edge 226A of the extension 226 It has a coat layer 229 superimposed on the metal foil 221 in the area. Thus, in the positive electrode tab 224, a portion where stress tends to concentrate when the positive electrode 220 tries to move to the separator 215 side with the extension part 226 in contact with the end edge of the separator 215 (the end edge of the positive electrode tab 224 The tear from the bending part) is suppressed.
しかも、コート層２２９が絶縁性を有しているため、セパレータ２１５がずれてコート層２２９と負極２１０とが接触しても短絡しない。即ち、セパレータ２１５のずれによる負極２１０と正極２２０との短絡がより生じ難くなる。 Moreover, since the coat layer 229 has an insulating property, short circuit does not occur even if the separator 215 is shifted and the coat layer 229 and the negative electrode 210 come in contact with each other. That is, a short circuit between the negative electrode 210 and the positive electrode 220 due to the displacement of the separator 215 is less likely to occur.
本実施形態の電極体２では、延出部２２６が、第一部材２１のターン部２３２におけるＹ軸方向の端縁より外側に配置されている。ここで、ターン部２３２は、第一部材２１が折り返されている部位であり、該ターン部２３２では、平坦部３２１に比べ、ターン軸Ｓ方向（Ｙ軸方向）からの力に対する強度（例えば、座屈強度等）が向上している。このため、ターン部２３２にターン軸Ｓ方向から延出部２２６を当接させることで、延出部２２６がセパレータ２１５（ターン部２３２）の端縁に当接した状態で正極２２０がセパレータ２１５側へ移動しようとしたときの該セパレータ２１５の変形が抑えられる。これにより、正極２２０のセパレータ２１５側への移動がより確実に抑えられる。 In the electrode body 2 of the present embodiment, the extending portion 226 is disposed outside the end edge of the turn portion 232 of the first member 21 in the Y-axis direction. Here, the turn portion 232 is a portion where the first member 21 is folded back, and in the turn portion 232, compared to the flat portion 321, the strength (for example, the strength against the force from the turn axis S direction (Y axis direction)) The buckling strength etc. is improved. Therefore, by bringing the extension part 226 into contact with the turn part 232 from the direction of the turn axis S, the positive electrode 220 is on the side of the separator 215 with the extension part 226 in contact with the end edge of the separator 215 (turn part 232). Deformation of the separator 215 when it is attempted to move to the side is suppressed. Thereby, the movement of the positive electrode 220 to the separator 215 side can be more reliably suppressed.
また、本実施形態の電極体２では、第一部材２１が第一の折り返し部２３Ａと第二の折り返し部２３Ｂとが交互に配置されたつづら折り状態であり、正極２２０が、各折り返し部２３Ａ、２３Ｂの内側に配置されている。このように、電極体２においてＺ軸方向の一方側の端部と他方側の端部とにターン部２３２が配置されるため、ターン軸Ｓ方向（Ｙ軸方向）からの力に対する電極体２の強度が向上する。しかも、第一の折り返し部２３Ａの内側と第二の折り返し部２３Ｂの内側とに配置された各正極２２０のセパレータ２１５側への移動（セパレータ２１５のＹ軸方向の端縁から突出している部位の折り返し部２３Ａ、２３Ｂ内側への入り込み）も抑えられる。 Further, in the electrode body 2 of the present embodiment, the first member 21 is in a zigzag state in which the first folded portion 23A and the second folded portion 23B are alternately arranged, and the positive electrode 220 is each folded portion 23A, It is located inside 23B. As described above, since the turn portion 232 is disposed at the end on one side in the Z-axis direction and the end on the other side in the electrode body 2, the electrode body 2 against the force from the turn axis S direction (Y-axis direction) The strength of the In addition, the movement of each positive electrode 220 disposed on the inner side of the first folded portion 23A and the inner side of the second folded portion 23B toward the separator 215 (at a portion projecting from the edge of the separator 215 in the Y-axis direction) Intruding inside the folded portions 23A and 23B is also suppressed.
また、本実施形態の電極体２では、負極本体（負極活物質層形成部）２１３を覆うように負極２１０にセパレータ２１５が重ねられている第一部材２１がつづら折り状態であり、各折り返し部２３の内側に正極２２０が配置されている。 Further, in the electrode body 2 of the present embodiment, the first member 21 in which the separator 215 is superimposed on the negative electrode 210 so as to cover the negative electrode main body (negative electrode active material layer forming portion) 213 is in a zigzag state. The positive electrode 220 is disposed inside the
かかる構成によれば、正極２２０の正極タブ（活物質層非形成部）２２４が各折り返し部２３の内側へ入り込むのが抑えられる（即ち、正極２２０の正極タブ（活物質層非形成部）２２４と負極２１０の負極本体（活物質層形成部）２１３とがセパレータ２１５を介して対向することが防がれる）。これにより、セパレータ２１５の位置ずれや損傷等による正極２２０の正極タブ（活物質層非形成部）２２４と負極２１０の負極本体（活物質層形成部）２１３との短絡が抑えられる。即ち、本実施形態のようなリチウムイオン二次電池（蓄電素子）１においては、正極２２０の正極タブ（活物質層非形成部）２２４と負極２１０の負極本体２１３（負極活物質層２１２）との接触を最も避けなければならないが、本実施形態の蓄電素子１では、正極２２０が負極２１０に対して移動することで生じるセパレータ２１５を介した正極タブ２２４と負極本体２１３との対向を防ぎ、これにより、万一、セパレータ２１５がずれたり損傷したりしたとしても、正極タブ２２４と負極本体２１３とが接触（短絡）することを防いでいる。 According to this configuration, the positive electrode tab (active material layer non-forming portion) 224 of the positive electrode 220 can be prevented from entering the inside of each folded portion 23 (that is, the positive electrode tab (active material layer non-forming portion) 224 of the positive electrode 220 And the negative electrode main body (active material layer forming portion) 213 of the negative electrode 210 are prevented from facing each other through the separator 215). Thereby, a short circuit between the positive electrode tab (active material layer non-forming portion) 224 of the positive electrode 220 and the negative electrode main body (active material layer forming portion) 213 of the negative electrode 210 due to displacement or damage of the separator 215 can be suppressed. That is, in the lithium ion secondary battery (storage element) 1 as in this embodiment, the positive electrode tab (active material layer non-forming portion) 224 of the positive electrode 220 and the negative electrode main body 213 (negative electrode active material layer 212) of the negative electrode 210 However, in the storage element 1 of the present embodiment, the positive electrode 220 prevents the facing of the positive electrode tab 224 and the negative electrode body 213 via the separator 215 which is caused by the movement with respect to the negative electrode 210. Thus, even if the separator 215 is displaced or damaged, the positive electrode tab 224 and the negative electrode body 213 are prevented from contacting (shorting).
尚、本発明の蓄電素子は、上記実施形態に限定されるものではなく、本発明の要旨を逸脱しない範囲内において種々変更を加え得ることは勿論である。例えば、ある実施形態の構成に他の実施形態の構成を追加することができ、また、ある実施形態の構成の一部を他の実施形態の構成に置き換えることができる。さらに、ある実施形態の構成の一部を削除することができる。 The storage element of the present invention is not limited to the above embodiment, and it goes without saying that various modifications can be made without departing from the scope of the present invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, and part of the configuration of one embodiment can be replaced with the configuration of another embodiment. In addition, some of the configuration of an embodiment can be deleted.
延出部２２６の具体的な形状は限定されない。延出部２２６は、Ｙ軸方向から見てその一部が正極２２０（該延出部２２６を含む正極２２０）と隣接するセパレータ２１５の端縁と重なる部位を有していればよい。このように延出部２２６がＹ軸方向から見てセパレータ２１５の端縁と重なる部位を有していれば、正極２２０がＹ軸方向のセパレータ２１５側に移動し又は移動しようとしたときに、延出部２２６の前記部位が前記セパレータ２１５の端縁に当接し、又は当接していることで、該延出部２２６が前記セパレータ２１５の端縁に当接する位置よりも、正極２２０の前記セパレータ２１５側への移動が抑制又は規制される。 The specific shape of the extension part 226 is not limited. The extension portion 226 may have a portion overlapping with the end edge of the separator 215 adjacent to the positive electrode 220 (the positive electrode 220 including the extension portion 226) as viewed in the Y-axis direction. As described above, when the extension part 226 has a portion overlapping the end edge of the separator 215 as viewed from the Y-axis direction, when the positive electrode 220 moves or tries to move to the separator 215 side in the Y-axis direction, The portion of the extension portion 226 is in contact with or in contact with the edge of the separator 215, so that the separator of the positive electrode 220 is more than a position where the extension portion 226 is in contact with the edge of the separator 215. Movement to the 215 side is suppressed or regulated.
上記実施形態の負極２１０では、複数の負極タブ２１４が長尺方向に間隔をあけて配置されているが、この構成に限定されない。例えば、負極タブ２１４は、負極本体２１３の長手方向の全域において連続していてもよい。 In the negative electrode 210 of the above embodiment, the plurality of negative electrode tabs 214 are arranged at intervals in the longitudinal direction, but the present invention is not limited to this configuration. For example, the negative electrode tab 214 may be continuous over the entire area of the negative electrode body 213 in the longitudinal direction.
上記実施形態の正極タブ２２４には、切り欠き２２５１が設けられているが、この構成に限定されない。正極タブ２２４は、切り欠き２２５１の無い構成でもよい。 Although the notch 2251 is provided in the positive electrode tab 224 of the said embodiment, it is not limited to this structure. The positive electrode tab 224 may be configured without the notch 2251.
上記実施形態の第一部材２１は、負極２１０とセパレータ２１５とを含んでいるが、この構成に限定されない。第一部材２１は、セパレータ２１５のみを含む構成でもよい。この場合、例えば図９に示すように、各第一の折り返し部２３Ａに枚葉状の負極（第二部材）２１０が配置され、各第二の折り返し部２３Ｂに枚葉状の正極（第二部材）２２０が配置される。このとき、負極２１０は、上記実施形態の正極２２０と同様の構成（延出部２２６を有する構成）であってもよい。即ち、負極２１０と正極２２０のそれぞれが、延出部２２６を有していてもよい。 Although the 1st member 21 of the said embodiment contains the negative electrode 210 and the separator 215, it is not limited to this structure. The first member 21 may be configured to include only the separator 215. In this case, for example, as shown in FIG. 9, a sheet-like negative electrode (second member) 210 is disposed in each first folded portion 23A, and a sheet-like positive electrode (second member) is disposed in each second folded portion 23B. 220 are arranged. At this time, the negative electrode 210 may have a configuration similar to that of the positive electrode 220 of the above embodiment (a configuration having the extending portion 226). That is, each of the negative electrode 210 and the positive electrode 220 may have the extension part 226.
また、上記実施形態の電極体２では、第一部材２１（負極２１０及びセパレータ２１５）がつづら折り状態であるが、この構成に限定されない。負極２１０、正極２２０、及びセパレータ２１５がそれぞれ短冊状（枚葉状）であり、電極体２が、セパレータ２１５を介して負極２１０と正極２２０とが交互に積層されているいわゆるスタック型であってもよい。この場合、負極２１０及び正極２２０の少なくとも一方の活物質層非形成部（負極タブ２１４、正極タブ２２４）がセパレータ２１５の端縁から突出し、この活物質層非形成部２１４、２２４のセパレータ２１５から突出している部位から延出部２２６が延びている。そして、この延出部２２６は、活物質層非形成部２１４、２２４の突出方向から見てセパレータ２１５の前記端縁と重なる部位を有している。 Moreover, in the electrode body 2 of the said embodiment, although the 1st member 21 (the negative electrode 210 and the separator 215) is a zigzag folding state, it is not limited to this structure. The so-called stack type in which the negative electrode 210, the positive electrode 220, and the separator 215 are each strip-like (sheet-like), and the electrode body 2 is alternately laminated with the negative electrode 210 and the positive electrode 220 via the separator 215 Good. In this case, at least one active material layer non-forming portion (negative electrode tab 214, positive electrode tab 224) of the negative electrode 210 and the positive electrode 220 protrudes from the edge of the separator 215, and from the separator 215 of the active material layer non-forming portion 214, 224. An extension 226 extends from the protruding portion. The extending portion 226 has a portion overlapping with the edge of the separator 215 when viewed from the direction in which the active material layer non-forming portions 214 and 224 protrude.
上記実施形態の正極２２０（第二部材２２）では、延出部２２６は、Ｙ軸方向における折り返し部２３の一方側のみに配置されているが、この構成に限定されない。正極２２０において、延出部２２６は、Ｙ軸方向における折り返し部２３の他方側にも配置されてもよい。即ち、正極２２０において、延出部２２６は、Ｙ軸方向における折り返し部２３の一方側と他方側との両側に配置されてもよい。かかる構成によれば、正極２２０（第二部材２２）のＹ軸方向の一方側と他方側とへの移動が規制される。 In the positive electrode 220 (second member 22) of the above-described embodiment, the extending portion 226 is disposed only on one side of the folded portion 23 in the Y-axis direction, but is not limited to this configuration. In the positive electrode 220, the extension part 226 may be disposed on the other side of the folded part 23 in the Y-axis direction. That is, in the positive electrode 220, the extending portions 226 may be disposed on both sides of the folded portion 23 in the Y-axis direction. According to this configuration, the movement of the positive electrode 220 (second member 22) to one side and the other side in the Y-axis direction is restricted.
上記実施形態の正極２２０は、コート層２２９を有しているが、この構成に限定されない。正極２２０は、コート層の無い構成でもよい。 The positive electrode 220 of the above embodiment has the coat layer 229, but is not limited to this configuration. The positive electrode 220 may have a configuration without a coat layer.
また、上記実施形態においては、蓄電素子１が充放電可能な非水電解質二次電池（例えばリチウムイオン二次電池）として用いられる場合について説明したが、蓄電素子の種類や大きさ（容量）は任意である。また、上記実施形態において、蓄電素子１の一例として、リチウムイオン二次電池について説明したが、これに限定されるものではない。例えば、本発明は、種々の二次電池、その他、一次電池や、電気二重層キャパシタ等のキャパシタの蓄電素子にも適用可能である。 In the above embodiment, although the case where the storage element 1 is used as a chargeable / dischargeable non-aqueous electrolyte secondary battery (for example, a lithium ion secondary battery) has been described, the type and size (capacity) of the storage element are It is optional. Moreover, in the said embodiment, although the lithium ion secondary battery was demonstrated as an example of the electrical storage element 1, it is not limited to this. For example, the present invention can be applied to various secondary batteries, as well as storage devices of capacitors such as primary batteries and electric double layer capacitors.
蓄電素子（例えば電池）１は、図１０に示すような蓄電装置（蓄電素子が電池の場合は電池モジュール）１１に用いられてもよい。蓄電装置１１は、少なくとも二つの蓄電素子１と、二つの（異なる）蓄電素子１同士を電気的に接続するバスバ部材１２と、を有する。この場合、本発明の技術が少なくとも一つの蓄電素子１に適用されていればよい。 The storage element (for example, battery) 1 may be used in a storage device (a battery module if the storage element is a battery) 11 as shown in FIG. Power storage device 11 has at least two power storage elements 1 and a bus bar member 12 electrically connecting two (different) power storage elements 1 with each other. In this case, the technique of the present invention may be applied to at least one storage element 1.
１…蓄電素子、２…電極体、２１…第一部材、２１Ａ…山折り線、２１Ｂ…谷折り線、２１０…負極（電極）、２１０Ａ…第一部材本体、２１０Ｂ…第一部材タブ、２１１…金属箔、２１２…負極活物質層、２１３…負極本体（活物質層形成部、負極活物質層形成部）、２１３Ａ…負極本体の長辺、２１４…負極タブ（活物質層非形成部、負極活物質層非形成部）、２１５…セパレータ、２２…第二部材、２２０…正極（電極）、２２１…金属箔、２２２…正極活物質層、２２３…正極本体（活物質層形成部、正極活物質層形成部）、２２４…正極タブ（活物質層非形成部、正極活物質層非形成部）、２２５…タブ本体、２２５Ａ…タブ本体の端縁、２２５１…タブ本体、２２６…延出部、２２６Ａ…端縁、２２９…コート層、２３…折り返し部、２３Ａ…第一の折り返し部、２３Ｂ…第二の折り返し部、２３１…平坦部、２３１Ａ…第一の面、２３１Ｂ…第二の面、２３２…ターン部、２３２Ａ…第一ターン部、２３２Ｂ…第二ターン部、３…ケース、３１…ケース本体、３１０…開口周縁部、３１１…閉塞部、３１２…胴部、３１３…長壁部、３１４…短壁部、３２…蓋板、４…外部端子、５…集電体、５１…第一接続部、５２…第二接続部、６…クリップ部材、７…絶縁部材、１１…蓄電装置、１２…バスバ部材、５００…電池、５０１…負極電極板（長尺電極板）、５０２…銅箔、５０３…負極活物質層、５０４…正極電極板（短冊状電極板）、５０５…アルミニウム箔、５０６…正極活物質層、５０７…セパレータ、５０８…長尺物、ｂ１…正極本体とタブ本体との境界位置、ｂ２…タブ本体の端縁と延出部の端縁との境界位置、Ｓ…ターン軸、α…切断予定線、α１…第一部位、α２…第二部位、α３…第三部位 DESCRIPTION OF SYMBOLS 1 ... Storage element, 2 ... electrode body, 21 ... 1st member, 21A ... mountain fold line, 21B ... valley fold line, 210 ... negative electrode (electrode), 210A ... 1st member main body, 210B ... 1st member tab, 211 ... Metal foil, 212 ... negative electrode active material layer, 213 ... negative electrode main body (active material layer forming portion, negative electrode active material layer forming portion), 213 A ... long side of negative electrode body, 214 ... negative electrode tab (active material layer non-forming portion, Negative electrode active material layer non-forming portion) 215 Separator 2 22 second member 220 positive electrode (electrode) 221 metal foil 222 positive electrode active material layer 223 positive electrode main body (active material layer forming portion, positive electrode Active material layer forming portion) 224 Positive electrode tab (active material layer non-forming portion, positive electrode active material layer non-forming portion) 225 Tab body 225A Edge of tab body 2251 Tab body 226 Extension Part, 226A ... edge, 229 ... coat layer, 23 ... turn back Portions 23A: first folded portion 23B: second folded portion 231: flat portion 231A: first surface 231B: second surface 232: turn portion 232A: first turn portion 232B ... 2nd turn part, 3 ... case, 31 ... case body, 310 ... opening peripheral part, 311 ... closing part, 312 ... body part, 313 ... long wall part, 314 ... short wall part, 32 ... lid plate, 4 ... outside Terminal 5, Current collector 51, First connection portion 52, Second connection portion 6, Clip member 7, Insulating member 11, Storage device 12, Bus bar member 500, Battery 501, Negative electrode Plate (long electrode plate), 502: copper foil, 503: negative electrode active material layer, 504: positive electrode plate (strip electrode plate), 505: aluminum foil, 506: positive electrode active material layer, 507: separator, 508: 508 Long object, b1 ... border between positive electrode body and tab body Location, the boundary position between the edge of the edge and the extended portion of b2 ... tub body, S ... turn axis, alpha ... cutting line, [alpha] 1 ... first site, [alpha] 2 ... second region, .alpha.3 ... third portion
Claims (5)
前記第一方向の寸法が前記活物質層形成部より大きなセパレータと、を有する電極体を備え、
前記電極と前記セパレータとは、前記活物質層非形成部が前記セパレータにおける前記第一方向の端縁から突出するように積層され、
前記活物質層非形成部は、該活物質層非形成部における前記セパレータの前記第一方向の端縁から突出している部位から延び且つ前記第一方向から見て前記端縁と重なる部位を有する延出部を備える、蓄電素子。 An electrode in which an active material layer forming portion on which a metal foil and an active material layer are superimposed and an active material layer non-forming portion on which the active material layer can not be superimposed on the metal foil are arranged in a first direction
An electrode body having a separator whose dimension in the first direction is larger than that of the active material layer forming portion,
The electrode and the separator are stacked such that the active material layer non-forming portion protrudes from an end edge of the separator in the first direction,
The active material layer non-forming portion extends from a portion of the active material layer non-forming portion that protrudes from the edge of the first direction of the separator and has a portion overlapping with the edge when viewed from the first direction A storage element comprising an extension part.
前記電極は、前記一対の平坦部の間に配置され、
前記延出部は、前記ターン部における前記第一方向の一方側の端縁より一方側に配置されている、請求項１又は２に記載の蓄電素子。 The separator includes a folded portion including a pair of parallel or substantially parallel flat portions, and a turn portion connecting ends of the pair of flat portions so as to turn around a turn axis extending in the first direction. Have
The electrode is disposed between the pair of flat portions,
The storage element according to claim 1, wherein the extension part is disposed on one side of an end edge on one side in the first direction in the turn part.
前記セパレータは、前記第一の折り返し部と前記第二の折り返し部とが交互に配置されたつづら折り状態であり、
前記電極は、前記第一の折り返し部の内側と前記第二の折り返し部の内側とのそれぞれに配置される、請求項３に記載の蓄電素子。 The folded portion includes a first folded portion in which one side of a second direction orthogonal to the first direction is opened, and a second folded portion in which the other side of the second direction is opened,
The separator is in a zigzag state in which the first folded portion and the second folded portion are alternately arranged;
The storage element according to claim 3, wherein the electrode is disposed on each of the inner side of the first folded portion and the inner side of the second folded portion.
前記電極体は、前記セパレータに重ねられ且つ該セパレータと共につづら折り状態である負極を有し、
前記負極では、金属箔及び負極活物質層が重ねられる負極活物質層形成部と金属箔に負極活物質層が重ねられない負極活物質層非形成部とが前記第一方向に並び、
前記負極活物質層形成部は、前記セパレータと重なっている、請求項４に記載の蓄電素子。 The electrode is a positive electrode,
The electrode body has a negative electrode that is superimposed on the separator and is in a zigzag state with the separator,
In the negative electrode, a negative electrode active material layer forming portion on which the metal foil and the negative electrode active material layer are stacked, and a negative electrode active material layer non-forming portion on which the negative electrode active material layer can not be stacked on the metal foil are arranged in the first direction.
The storage element according to claim 4, wherein the negative electrode active material layer forming portion overlaps the separator.
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