WO2017030369A1 - Procédé de fabrication de batterie rechargeable - Google Patents

Procédé de fabrication de batterie rechargeable Download PDF

Info

Publication number
WO2017030369A1
WO2017030369A1 PCT/KR2016/009045 KR2016009045W WO2017030369A1 WO 2017030369 A1 WO2017030369 A1 WO 2017030369A1 KR 2016009045 W KR2016009045 W KR 2016009045W WO 2017030369 A1 WO2017030369 A1 WO 2017030369A1
Authority
WO
WIPO (PCT)
Prior art keywords
secondary battery
present
charging
discharging
pressing
Prior art date
Application number
PCT/KR2016/009045
Other languages
English (en)
Korean (ko)
Inventor
김현태
김동명
류상백
Original Assignee
주식회사 엘지화학
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 주식회사 엘지화학 filed Critical 주식회사 엘지화학
Priority claimed from KR1020160104134A external-priority patent/KR20170021213A/ko
Publication of WO2017030369A1 publication Critical patent/WO2017030369A1/fr

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/44—Methods for charging or discharging
    • 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

Definitions

  • the present invention relates to a secondary battery manufacturing method, and more particularly to a secondary battery manufacturing method having a predetermined shape.
  • Cells or batteries that generate electric energy through physical or chemical reactions of materials and supply power to the outside cannot obtain AC power supplied to buildings according to the living environment surrounded by various electric and electronic devices. It is used when DC power is needed.
  • the primary battery is a consumable battery, commonly referred to as a battery.
  • the secondary battery is a rechargeable battery manufactured using a material that can be repeated a number of redox process between the current and the material, the power is charged when the reduction reaction to the material by the electric current, the oxidation reaction to the material When performed, the power is discharged. As the charge-discharge is repeatedly performed, electricity is generated.
  • the manufacturing method of the lithium secondary battery has an advantage that since the electrolyte is in the form of a solid or a gel, even if the battery is damaged due to an accident, there is little risk of ignition or explosion because the electrolyte does not leak out, thereby ensuring safety and high energy efficiency.
  • a solid metal casing it can be manufactured in various sizes and shapes according to the use, it can be manufactured to a thickness of less than 3mm, weight can be reduced by more than 30%, mass production and large battery manufacturing is possible .
  • Korean Patent Laid-Open No. 10-2015-0050319 discloses a conventional method for manufacturing a curved secondary battery.
  • This conventional technique is for molding a secondary battery having a radius of curvature.
  • the conventional technology is to form a radius of curvature by pressing the secondary battery of the finished product, there is a problem that the deformation strength is weak and easily deformed after completion of the shape.
  • the present invention has been made by the above necessity, the object of the present invention is to manufacture a secondary battery that can enhance the resistance strength to the restoring force to prevent deformation of the secondary battery while forming a secondary battery of a predetermined shape. To provide.
  • the method of manufacturing a secondary battery according to the present invention includes a preparation step of preparing a secondary battery in which an electrode assembly is embedded and an activation step of activating the secondary battery, wherein the activation step is a charge / discharge step of charging or discharging the secondary battery. And it is carried out at the same time as the charge and discharge step characterized in that it comprises a molding step of molding the secondary battery to a predetermined shape using a pressure jig.
  • the active material of the electrode assembly may be cured.
  • the secondary battery may be molded to bend.
  • the secondary battery of a predetermined shape can be manufactured by pressing the secondary battery with a pressure jig together with a charging or discharging process.
  • the active material of the electrode assembly is cured to increase the resistance strength to the restoring force after completion of the shape of the secondary battery.
  • the active material of the electrode assembly is cured to increase the resistance strength of the secondary battery, thereby preventing the secondary battery from being deformed.
  • FIG. 1 is a flowchart sequentially illustrating a method of manufacturing a secondary battery according to an embodiment of the present invention.
  • FIG. 2 is a configuration diagram illustrating a secondary battery in a preparation step of FIG. 1 from a left side thereof.
  • FIG. 3 is a configuration diagram illustrating the molding of the secondary battery by pressing in the activation step of FIG. 1 from the left side.
  • FIG. 4 is a configuration diagram illustrating the secondary battery formed in FIG. 3 from the left side.
  • Figure 5 is a block diagram showing the left side to press the secondary battery molded in the activation step in accordance with another embodiment of the present invention.
  • FIG. 6 is a configuration diagram illustrating the secondary battery formed in FIG. 5 from the left side.
  • FIG. 7 is a block diagram illustrating the molding of the secondary battery by pressing the secondary battery in an activation step according to another embodiment of the present invention.
  • FIG. 8 is a configuration diagram illustrating the secondary battery formed in FIG. 7 from the left side.
  • FIG. 9 is a block diagram showing the left side of pressing and molding the secondary battery in the activation step according to another embodiment of the present invention.
  • FIG. 10 is a configuration diagram illustrating the secondary battery formed in FIG. 9 from the left side.
  • FIG. 11 is a block diagram illustrating the secondary battery of the preparation step of FIG. 1 in a plan view.
  • FIG. 12 is a block diagram illustrating a plan view of pressing and molding a secondary battery in an activation step according to another embodiment of the present invention.
  • FIG. 13 is a configuration diagram illustrating the rechargeable battery formed in FIG. 12 in a plan view.
  • FIG. 14 is a block diagram illustrating a plan view of pressing and molding a secondary battery in an activation step according to another embodiment of the present invention.
  • FIG. 15 is a configuration diagram illustrating the rechargeable battery formed in FIG. 14 in a plan view.
  • FIG. 1 is a flowchart sequentially illustrating a method of manufacturing a secondary battery according to an embodiment of the present invention.
  • a method of manufacturing a secondary battery according to an exemplary embodiment of the present invention includes a preparation step S1 and an activation step S2.
  • the activation step (S2) includes a charge and discharge step (S2-1) and the molding step (S2-2).
  • the preparation step S1 is a step of preparing a general secondary battery 1 in which an electrode assembly is embedded in the pouch 5 and an electrolyte is filled in the pouch 5 together with the electrode assembly.
  • the secondary battery 1 according to the present invention together with FIG. 2 will be described in more detail.
  • FIG. 2 is a configuration diagram illustrating a secondary battery in a preparation step of FIG. 1 from a left side thereof.
  • the secondary battery 1 according to the present invention may be a pouch-type lithium secondary battery, but is not limited to a shape or a type if the lithium secondary battery is satisfied.
  • the electrode assembly can be produced by, for example, laminating a plurality of times a positive electrode to which a positive electrode active material is applied, a negative electrode to which a negative electrode active material is applied, and a separator interposed between the positive electrode and the negative electrode.
  • the present invention is not limited thereto, and the electrode assembly may be manufactured by winding a laminate in which a cathode, a separator, and a cathode are laminated in a jelly roll form.
  • the positive electrode may include a positive electrode active material portion coated with a positive electrode active material and a positive electrode non-coated portion not coated with the positive electrode active material.
  • the positive electrode active material may be a lithium-containing transition metal oxide such as LiCoO 2, LiNiO 2, LiMnO 2, LiMnO 4, or a lithium chalcogenide compound.
  • the positive electrode active material may be formed by applying a positive electrode active material to a portion of at least one surface of the aluminum plate, and the remaining portion of the aluminum plate not coated with the positive electrode active material may be a positive electrode non-coating portion.
  • the negative electrode may include a negative electrode active material portion coated with a negative electrode active material and a negative electrode non-coated portion not coated with the negative electrode active material.
  • the negative electrode active material may be crystalline carbon, amorphous carbon, carbon composite, carbon material such as carbon fiber, lithium metal, lithium alloy, or the like.
  • the negative electrode active material may be formed by applying a negative electrode active material to a portion of at least one side of the copper plate, and the remaining portion of the copper plate not coated with the negative electrode active material may be a negative electrode non-coating portion.
  • the separator is, for example, any one selected from the group consisting of polyethylene (PE), polystyrene (PS), polypropylene (PP) and copolymers of polyethylene (PE) and polypropylene (PP). It can be prepared by coating a polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP co-polymer).
  • PE polyethylene
  • PS polystyrene
  • PP polypropylene
  • PVDF-HFP co-polymer polyvinylidene fluoride-hexafluoropropylene copolymer
  • the electrode tabs 3 are attached to the positive and negative electrode portions, respectively, and the electrode tabs 3 may be led out through the pouch 5.
  • the pouch 5 seals the electrode assembly and houses the electrolyte together with the electrode assembly therein.
  • the pouch 5 may be formed of, for example, a three-layer structure of an insulating layer, a metal layer, and an insulating layer.
  • the metal layer may be formed of aluminum, steel, stainless steel, or the like
  • the insulating layer may be formed of modified polypropylene (CPP), polyethylene terephthalate (PET), nylon, or the like, but is not limited thereto.
  • the pouch 5 may include an accommodating part forming a first surface and a lid part forming a second surface.
  • the receiving part is provided with an accommodating space for accommodating the electrode assembly.
  • the lid part continuously formed on one side of the accommodating part is folded onto the accommodating part, and then the accommodating part is formed at the edge of the accommodating space.
  • the lid part is melt bonded.
  • the activation step (S2) is a step of activating the secondary battery 1 prepared in the preparation step (S1), and includes a charging and discharging step (S2-1) and a molding step (S2-2).
  • the assembly is completed and the charging of the secondary battery in the discharge state is completed and activated through aging.
  • the assembled secondary battery 1 in the discharged state is placed in the active equipment, and the electrodes are firstly charged by connecting the electrodes.
  • a SEI Solid Electrolyte Inter-phase
  • a SEI Solid Electrolyte Inter-phase
  • the cells in which the discharge and charge processes are completed are aged for two to three weeks.
  • the electrolyte is evenly distributed on the electrode.
  • the time for detecting metal impurities such as nickel (Ni), iron (Fe), copper (Cu), etc. may be obtained through aging.
  • the activation step S2 is performed at the same time as the charging / discharging step S2-1, and presses the secondary battery 1 using the pressure jig 10 to form a predetermined shape.
  • Step S2-2 is included.
  • the forming step (S2-2) is a process that is performed simultaneously with the charging and discharging step (S2-1), and may be a step of pressing the secondary battery 1 using the pressing jig 10 to form a predetermined shape. .
  • the activation step S2 of the present invention is activated secondary battery because the molding step S-2 for pressurizing the secondary battery 1 is performed simultaneously with the charging and discharging step S2-1 of the secondary battery 1.
  • the active material of the electrode assembly of (1) is cured together with molding, thereby enhancing the resistance strength against deformation of the secondary battery 1 molded into a constant shape.
  • the secondary battery 1 according to the present invention in which the resistance strength against shape deformation is enhanced, can prevent a phenomenon in which the secondary battery 1 formed in a predetermined shape is deformed to another shape.
  • the pressing jig 10 used in the molding step (S2-2) is for pressing the secondary battery 1 on opposite sides to form the secondary battery 1 into a predetermined shape, and is larger than the area of the secondary battery 1. It is desirable to have a large area and to make a pair.
  • the pair of pressing jig 10 is not necessarily the same in shape and size.
  • the pressing jig 10 is formed so as to correspond to the shape of the secondary battery 1 required, and the shape thereof is not limited.
  • FIG. 3 is a configuration diagram illustrating the molding of the secondary battery by pressing in the activation step of FIG. 1 from the left side.
  • a pair of pressure jig 10 curved in one direction causes the secondary battery 1 to be indicated by an arrow in FIG. 3. Pressurize on both sides opposite to phosphorus.
  • FIG. 4 is a configuration diagram illustrating the secondary battery formed in FIG. 3 from the left side.
  • the secondary battery 1 pressed by the pair of pressing jigs 10 curved in one direction is formed to be curved in one direction.
  • Figure 5 is a block diagram showing the left side to press the secondary battery molded in the activation step in accordance with another embodiment of the present invention.
  • a pair of pressure jig 10 bent in one direction causes the secondary battery 1 to be indicated by an arrow in FIG. 5. Pressurize on both sides opposite to phosphorus.
  • FIG. 6 is a configuration diagram illustrating the secondary battery formed in FIG. 5 from the left side.
  • the secondary battery 1 pressed by the pair of pressing jigs 10 bent in one direction is formed to be bent in one direction.
  • FIG. 7 is a block diagram illustrating the molding of the secondary battery by pressing the secondary battery in an activation step according to another embodiment of the present invention.
  • a pair of pressure jig 10 curved in two directions causes the secondary battery 1 to be indicated by an arrow in FIG. 7. Pressurize on both sides opposite to phosphorus.
  • FIG. 8 is a configuration diagram illustrating the secondary battery formed in FIG. 7 from the left side.
  • the secondary battery 1 pressed by a pair of pressing jigs 10 curved in two directions is formed to be curved in two directions.
  • FIG. 9 is a block diagram showing the left side of pressing and molding the secondary battery in the activation step according to another embodiment of the present invention.
  • a pair of pressure jig 10 bent in two directions causes the secondary battery 1 to be indicated by an arrow in FIG. 9. Pressurize on both sides opposite to phosphorus.
  • FIG. 10 is a configuration diagram illustrating the secondary battery formed in FIG. 9 from the left side.
  • the secondary battery 1 pressed by a pair of pressing jigs 10 bent in two directions is formed to be bent in two directions.
  • FIG. 11 is a schematic view showing a secondary battery in a preparation step of FIG. 1 in plan view
  • FIG. 12 is a schematic view showing a planar view of pressing and molding a secondary battery in an activation step according to another embodiment of the present invention. .
  • a pair of pressure jig 10 curved at both ends in one direction may move the secondary battery 1 to an arrow in FIG. 12. Pressurizes on opposite sides of the indicated direction.
  • FIG. 13 is a configuration diagram illustrating the rechargeable battery formed in FIG. 12 in a plan view.
  • the secondary battery 1 pressurized by a pair of pressing jigs 10 curved at both ends is formed to be curved at both ends.
  • FIG. 14 is a block diagram illustrating a plan view of pressing and molding a secondary battery in an activation step according to another embodiment of the present invention.
  • a pair of pressure jig 10 curved at both ends in two directions causes the secondary battery 1 to have arrows as shown in FIG. 14. Pressurize on opposite sides of the indicated direction.
  • FIG. 15 is a configuration diagram illustrating the rechargeable battery formed in FIG. 14 in a plan view.
  • the secondary battery 1 pressurized by a pair of pressing jigs 10 curved at both ends is formed to be curved at both ends.
  • the secondary battery 1 having a predetermined shape that is bent or bent has a shape that is bent to have a predetermined radius of curvature or bent to have a predetermined angle through a molding process.
  • the secondary battery 1 having a predetermined shape to be bent or bent may have a constant curved surface or inclination according to the shape of the electronic device (not shown) to be mounted, whereby the electronic device and the secondary battery 1 The gap is removed, so that the internal space of the electronic device can be efficiently used, and damage to the secondary battery 1 can be prevented as the secondary battery 1 flows inside the electronic device.
  • the present invention by pressing the secondary battery 1 in the activation step of the secondary battery 1 to form the secondary battery 1, the active material of the electrode assembly embedded in the secondary battery 1 to cure the secondary battery After completion of the shape of (1) there is an advantage that can strengthen the resistance strength for restoration.
  • the active material of the electrode assembly is cured, thereby increasing the resistance strength to the restoring force after completing the shape of the secondary battery.
  • the active material of the electrode assembly is cured to increase the resistance strength of the secondary battery, thereby preventing the secondary battery from deforming. have.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Secondary Cells (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

La présente invention concerne un procédé de fabrication d'une batterie rechargeable ayant une forme prédéterminée. En outre, la présente invention comprend les étapes suivantes : une étape de préparation consistant à préparer une batterie rechargeable équipée d'un ensemble à électrodes; et une étape d'activation consistant à activer la batterie rechargeable, l'étape d'activation comprenant une étape de charge/décharge consistant à charger ou décharger la batterie rechargeable et une étape de moulage consistant à mouler la batterie rechargeable en une forme prédéterminée à l'aide d'un gabarit de pression, l'étape de charge/décharge et l'étape de moulage étant effectuées simultanément.
PCT/KR2016/009045 2015-08-17 2016-08-17 Procédé de fabrication de batterie rechargeable WO2017030369A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
KR10-2015-0115318 2015-08-17
KR20150115318 2015-08-17
KR10-2016-0104134 2016-08-17
KR1020160104134A KR20170021213A (ko) 2015-08-17 2016-08-17 이차전지의 제작방법

Publications (1)

Publication Number Publication Date
WO2017030369A1 true WO2017030369A1 (fr) 2017-02-23

Family

ID=58051818

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/KR2016/009045 WO2017030369A1 (fr) 2015-08-17 2016-08-17 Procédé de fabrication de batterie rechargeable

Country Status (1)

Country Link
WO (1) WO2017030369A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030039883A1 (en) * 2001-08-24 2003-02-27 Notten Petrus Henricus Laurentius Method of manufacturing a lithium battery, a lithium battery and an electrical appliance
US20030108787A1 (en) * 2000-11-21 2003-06-12 Takahiro Endo Polymer electrolyte battery and method of producing same
KR101161136B1 (ko) * 2011-05-17 2012-06-29 주식회사 엘지화학 휘어진 형상의 전지셀 및 이를 포함하는 전지팩
KR101464965B1 (ko) * 2012-02-27 2014-11-25 주식회사 엘지화학 휘어진 형상의 전지셀의 제조방법
KR20150050319A (ko) * 2013-10-29 2015-05-08 삼성에스디아이 주식회사 커브드 이차 전지의 제조 방법

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030108787A1 (en) * 2000-11-21 2003-06-12 Takahiro Endo Polymer electrolyte battery and method of producing same
US20030039883A1 (en) * 2001-08-24 2003-02-27 Notten Petrus Henricus Laurentius Method of manufacturing a lithium battery, a lithium battery and an electrical appliance
KR101161136B1 (ko) * 2011-05-17 2012-06-29 주식회사 엘지화학 휘어진 형상의 전지셀 및 이를 포함하는 전지팩
KR101464965B1 (ko) * 2012-02-27 2014-11-25 주식회사 엘지화학 휘어진 형상의 전지셀의 제조방법
KR20150050319A (ko) * 2013-10-29 2015-05-08 삼성에스디아이 주식회사 커브드 이차 전지의 제조 방법

Similar Documents

Publication Publication Date Title
WO2015122667A1 (fr) Batterie rechargeable de type pochette comprenant une partie d'étanchéité à évidement
WO2014073751A1 (fr) Ensemble d'électrodes étagées, batterie secondaire, parc de batteries et dispositif le comprenant ainsi que procédé de fabrication associé
WO2020159306A1 (fr) Procédé de fabrication d'ensemble d'électrodes, et électrode et batterie secondaire ainsi fabriquées
WO2013151249A1 (fr) Cellule de batterie à structure en escalier
WO2014017864A1 (fr) Accumulateur
WO2009113799A2 (fr) Élément de batterie incurvé, et bloc-batterie le comprenant
WO2014104728A1 (fr) Batterie secondaire de type poche ayant une marge de scellage pour durabilité améliorée
WO2011099793A2 (fr) Batterie lithium rechargeable en forme de poche
WO2013095057A1 (fr) Assemblage d'électrodes de type roulé en gelée avec revêtement à motif de matériaux actifs sur celles-ci, et batterie secondaire le comprenant
WO2013180449A1 (fr) Ensemble électrode, élément de batterie, procédé de fabrication pour un ensemble électrode et procédé de fabrication pour un élément de batterie
WO2019078453A1 (fr) Boîtier de batterie de type poche comprenant une structure anti-fissure et son procédé de fabrication
WO2016137141A1 (fr) Batterie secondaire du type sachet
WO2018008926A1 (fr) Électrode, procédé de préparation d'électrode et rouleaux pour la préparation d'électrode
WO2015005652A1 (fr) Ensemble électrode, et batterie et dispositif comprenant celui-ci
WO2015122594A1 (fr) Élément de batterie comprenant un organe de prévention des rides
WO2021145624A1 (fr) Appareil et procédé de pliage de languette d'électrode
WO2016052867A1 (fr) Batterie cylindrique comprenant une partie de mise sous pression et son procédé de fabrication
WO2018044013A1 (fr) Procédé de fabrication d'électrode à l'aide d'un collecteur de courant ayant des pores ou des trous de type à pénétration formés sur celui-ci
WO2018066886A1 (fr) Batterie rechargeable
WO2021054603A1 (fr) Procédé de production de batterie secondaire et batterie secondaire
KR100943569B1 (ko) 폴리머 전해질 전지 및 그 형성 방법
KR20140048615A (ko) 원통형 이차전지의 프레스 장치 및 이를 이용한 이차전지의 제조방법
WO2021118197A1 (fr) Dispositif de fabrication d'ensemble d'électrodes, ensemble d'électrodes fabriqué par celui-ci et batterie secondaire
WO2021187726A1 (fr) Ensemble d'électrodes et son procédé de fabrication
WO2017030369A1 (fr) Procédé de fabrication de batterie rechargeable

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 16837311

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 16837311

Country of ref document: EP

Kind code of ref document: A1