WO2024133554A1 - Cellule secondaire - Google Patents

Cellule secondaire Download PDF

Info

Publication number
WO2024133554A1
WO2024133554A1 PCT/EP2023/087089 EP2023087089W WO2024133554A1 WO 2024133554 A1 WO2024133554 A1 WO 2024133554A1 EP 2023087089 W EP2023087089 W EP 2023087089W WO 2024133554 A1 WO2024133554 A1 WO 2024133554A1
Authority
WO
WIPO (PCT)
Prior art keywords
enclosure
lid
cylindrical
flange section
flat flange
Prior art date
Application number
PCT/EP2023/087089
Other languages
English (en)
Inventor
Michael Shaughnessy
Original Assignee
Northvolt Ab
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
Priority claimed from SE2251579A external-priority patent/SE546105C2/en
Application filed by Northvolt Ab filed Critical Northvolt Ab
Publication of WO2024133554A1 publication Critical patent/WO2024133554A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
    • H01M50/107—Primary casings; Jackets or wrappings characterised by their shape or physical structure having curved cross-section, e.g. round or elliptic
    • 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
    • H01M10/04—Construction or manufacture in general
    • H01M10/0431—Cells with wound or folded electrodes
    • 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
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/147—Lids or covers
    • H01M50/148—Lids or covers characterised by their shape
    • H01M50/152—Lids or covers characterised by their shape for cells having curved cross-section, e.g. round or elliptic
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/147—Lids or covers
    • H01M50/166—Lids or covers characterised by the methods of assembling casings with lids
    • H01M50/169—Lids or covers characterised by the methods of assembling casings with lids by welding, brazing or soldering
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • H01M50/536—Electrode connections inside a battery casing characterised by the method of fixing the leads to the electrodes, e.g. by welding
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • H01M50/538—Connection of several leads or tabs of wound or folded electrode stacks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/172—Arrangements of electric connectors penetrating the casing
    • H01M50/174—Arrangements of electric connectors penetrating the casing adapted for the shape of the cells
    • H01M50/179—Arrangements of electric connectors penetrating the casing adapted for the shape of the cells for cells having curved cross-section, e.g. round or elliptic

Definitions

  • the present disclosure generally pertains to cylindrical secondary cells and more precisely to a cylindrical secondary cell having an enclosure with an
  • lithium-ion batteries are becoming increasingly popular. They represent a type of rechargeable battery in which lithium ions move from the negative electrode to the positive electrode during discharge and back when charging.
  • a rechargeable battery typically comprises one or more secondary cells electrically connected to each other.
  • the present disclosure aims at providing highly reliable secondary cells that are efficient in manufacture.
  • the number of components is to be reduced and the assembly thereof is to be simplified.
  • a cylindrical secondary cell comprises:
  • a cylindrical enclosure comprising a first enclosure end, a second enclosure end and an enclosure sidewall extending between the enclosure ends, wherein at least one enclosure end is open, an electrode roll, and a lid, wherein: the cylindrical enclosure comprises a flat flange section extending from the enclosure sidewall at the open enclosure end, and the radially outermost portion of the lid is configured to abut and match the flat flange section of the cylindrical enclosure, and is welded to said flat flange section.
  • the enclosure sidewall does not comprise a beading groove. That is, the enclosure sidewall defines a cylinder having a constant radius along the entirety of its axial length. Put another way, the enclosure sidewall defines a constant cross-sectional profile between the enclosure ends.
  • the flat flange section may extend radially inwards or outwards from the enclosure sidewall.
  • the flat flange section may extend from the enclosure sidewall at an angle, preferably between 75-105 degrees, such as 90 degrees.
  • the flat flange section has a thickness equal to the thickness of the enclosure sidewall. That is, the flat flange section may be formed by folding, crimping, or otherwise shaping an outer brim of the cylindrical sidewall.
  • the cell further comprises a current collector disc arranged between the lid and the electrode roll and in direct electrical contact with the electrode roll.
  • the lid comprises at least one recessed contact portion that is configured to form the direct electrical contact with the current collector disc.
  • the recessed contact portion may be between 50% and 80% of the surface area of the lid. Such recesses may also advantageously provide improve gripping locations for the lid, thereby improving the ease of manufacture of the cell.
  • Manufacturing the cylindrical secondary cell substantially as described above comprises welding the radially outermost portion of the lid to the flat flange section of the cylindrical enclosure, forming a welded portion.
  • the method further comprises folding or machining the welded portion to thereby reduce the radial profile of the welded portion.
  • Figure 1 schematically illustrates a cylindrical secondary cell in crosssection
  • Figure 2 schematically shows a cylindrical secondary cell wherein the cylindrical enclosure comprises a flat flange section extending from the enclosure sidewall, according to an embodiment of the present disclosure
  • FIG. 3 schematically shows an alternative embodiment to the one of figure 2
  • Figure 4 schematically shows another alternative embodiment to the one of figure 2
  • Figure 5 schematically shows another alternative embodiment to the one of figure 2
  • Figures 6a-b schematically show another alternative embodiment to the one of figure 2, before and after a folding of the welded flange.
  • Figure 1 shows a cylindrical secondary cell 1 (hereinafter referred to as cell) in a cross-sectional side view.
  • the cell 1 is circular cylindrical.
  • the cell 1 comprises a cylindrical enclosure 2 having a first enclosure end 2a, an opposite second enclosure end 2b and an enclosure sidewall 2c that extends between the enclosure ends 2a, 2b.
  • the first and second enclosure ends 2a, 2b are circular.
  • the enclosure sidewall 2c is circular cylindrical.
  • the cell 1 and thus its enclosure sidewall 2c, may be elongate and extend along a longitudinal axis (Z-axis in figure 1 ).
  • the enclosure ends 2a, 2b may extend in planes (XY-planes in figure 1 ) that are perpendicular to the longitudinal axis.
  • the first enclosure end 2a, or first enclosure end side (top side in figure 1 ) may be formed in one piece with the enclosure sidewall 2c.
  • the second enclosure end 2b is open and a separate lid 10, as shown, is attached to the cylindrical enclosure 2 at the open enclosure end 2b.
  • the lid 10 forms the second enclosure end side (bottom side in figure 1 ).
  • both ends sides may be formed by respective lids.
  • the main portion of the enclosure sidewall 2c is essentially straight.
  • the main portion of the enclosure sidewall 2c extends in parallel with the longitudinal axis (Z-axis in figure 1 ) of the cell 1 .
  • the main portion of the enclosure sidewall 2c may be defined as at least 80 percent of the enclosure sidewall 2c extension along the longitudinal axis.
  • the cell 1 further comprises an electrode roll 20.
  • the electrode roll 20 comprises a first and a second conductive sheet 21 , 22 and separating means (not shown).
  • the separating means may also be termed separator.
  • the conductive sheets 21 , 22 and the separating means are rolled to form a circular cylindrical roll.
  • the conductive sheets 21 , 22 are coated with electrode coatings and on assembly of the cell 1 , the cylindrical enclosure 2 is filled with an electrolyte.
  • the coatings on the conductive sheets 21 , 22 act as cathode and anode, respectively.
  • the cathode, anode and electrolyte provide electrochemical energy storage. This principle is known per se, and the electrode roll 20 is commonly referred to as a jelly roll.
  • the conductive sheets 21 , 22 of the electrode roll 20 are axially offset in relation to one another, and each conductive sheet may comprise an end section that is not coated with electrode coating. Via the non-coated end sections, the respective ends of the electrode roll may be efficiently electrically connected to a respective assigned terminal of the cell 1 .
  • This design is known per se and commonly referred to as a tabless cell.
  • one 21 of the conductive sheets is in electrical contact with a terminal 23 at the closed end 2a of the cylindrical enclosure (which may be direct or via a current collecting disc), while the other 22 of the conductive sheets is in direct electrical contact with a current collector disc 24, which in turn is in electrical contact with the lid 10 (although these components are schematically shown as not touching).
  • the terminal 23 is isolated from the rest of the casing 2 so as to form an electrical contact for the cathode end.
  • the details of this end 2a of the cell 1 are not the focus of the present disclosure, and thus the terminal 23 is not shown in later figures.
  • Direct electrical contact may be referred to as physical contact.
  • the current collector disc 24 is welded, e.g. laser welded, to the conductive sheet 22, but in some embodiments, the current collector disc 24 is held or pressed against the conductive sheet 24 without welding.
  • the examples illustrated comprise a current collector disc 24, such a current collecting disc 24 is optional for connecting the conductive sheets 22 to the lid 10. That is, in some example implementations of the present disclosure, the cell 1 does not comprise the current collecting disc 24 and the lid 10 itself may be connected directly to the conductive sheet 22. In such embodiments, the lid 10 may be configured with at least one contact portion that is configured (e.g., recessed) to form direct electrical contact with the conductive sheets 22 of the electrode roll 20. Even in embodiments that comprise a current collector disc 24, the lid 10 may nonetheless comprise at least one recessed contact portion that is configured to form direct electrical contact with the current collector disc 24.
  • the cylindrical enclosure 2 comprises a flat flange section 2f extending from the enclosure sidewall 2c at the open enclosure end 2b, and the radially outermost portion of the lid 10 is configured to abut and match the flat flange section 2f of the cylindrical enclosure 2.
  • the lid 10 is welded to said flat flange section 2f, for example using laser welding, ultrasonic welding, or the like.
  • the flat flange section 2f may be formed by folding, crimping, bending, or similarly shaping the enclosure sidewall 2c at the open enclosure end 2b.
  • the flat flange section 2f is formed at a location on the enclosure sidewall 2c above the current collector disc 24.
  • the flat flange section 2f may be welded to the current collector disc 24.
  • the flat flange section 2f provides an advantageously larger surface area for welding the lid 10 to the cylindrical enclosure, thus enabling a better seal of the cell 1 by the lid 10.
  • the flat flange section 2f may be angled downwards into the interior of the cell 1 so as to push against the current collector disc 24 and hold it in place.
  • the flat flange section 2f is formed at a location on the enclosure sidewall 2c above the current collector disc 24 and the lid 10. As with the embodiment of figure 2, the flat flange section 2f may be angled downwards into the interior of the cell 1 so as to push against the lid 10 and the current collector disc 24 and hold them in place.
  • Such an embodiment may be manufactured by arranging the electrode roll 20 in the cylindrical enclosure 2, arranging the current collector disc 24 in direct electrical contact with the exposed uncoated conductive sheet 22, arranging the lid 10 in contact with the current collector disc 24, and then forming the flat flange section 2f over the lid 10.
  • the flat flange section 2f may be welded to the lid 10 at an edge of the flat flange section 2f so as to provide a welded joint that is easily inspectable and able to be electrically tested in-line in a manufacturing process for the cell 1.
  • the lid 10 may be welded or otherwise attached to the conductive sheets 22 before the electrode roll 20 and the lid 10 are arranged in the casing 2.
  • the edges of the open end 2b of the casing 2 can then be folded inward and over the lid 10 and welded thereto, e.g. using laser welding.
  • the lid 10 shown in figures 2 and 3 may be generally disc-shaped.
  • the lid 10 may have the general shape of a circular plate.
  • the lid 10 may comprise a circular disc that at the radially outer end comprises a flange 10f .
  • the flange 10f may extend from the circular disc in a direction away from or towards the cylindrical enclosure 2, or parallel or tangential to the disc when the lid 10 is attached to the cylindrical enclosure 2.
  • the circular disc and the flange 10f are preferably formed in one integral piece.
  • the current collector disc 24 may be welded to the sidewall 2c of the cylindrical enclosure 2.
  • the current collector disc 24 may comprise a flange to increase the contact area between the current collector disc 24 and the cylindrical enclosure 2.
  • the lid 10 may comprise a groove or notch for providing an opening in the lid 10 if a pressure to which the lid 10 is subjected, i.e. a pressure inside the cylindrical enclosure 2, reaches a threshold value. In such a situation, gas and/or other ejecta may be released out of the cell 1 through the opening formed in the lid 10.
  • the opening formed in the lid 10 as a result of the notch breaking may be referred to as a vent opening.
  • the lid 10 may be curved so as to adopt a partially spherical or ‘bowl’ shape.
  • the lid 10 is convex as viewed from an external of the cell 1 , but in other examples, the lid 10 may be concave.
  • the lid 10 is shaped so as to substantially abut the flat flange section 2f of the cylindrical enclosure 2.
  • Such a shape of the lid 10 may advantageously improve the resilience of the lid 10 against an increased internal pressure of the cell 1 .
  • the cell 1 may be configured such that the lid 10 does not protrude radially beyond the cylindrical enclosure 2. This may be beneficial as a great number of cells 1 are typically arranged next to one another or in a holder structure in a secondary battery. In this connection, a protruding lid may impede an assembly process or a tight arrangement of cells.
  • the flat flange section 2f may extend radially outwards from the enclosure sidewall 2c and the lid 10 may be sized so as to match the outer dimensions of the flat flange section 2f, i.e. , such that the lid 10 and flat flange section 2f are flush when arranged in abutment.
  • the lid 10 may be welded to the flat flange section 2f and then the welded connected part may be sized down (e.g., radially) so as to reduce the overall dimensions of the cell 1 .
  • the sizing down may comprise folding the welded flat flange section 2f and lid 10, as shown in figure 6b.
  • the sizing down may comprise grinding, cutting, or otherwise machining the flat flange section 2f and the lid 10 in a way that substantially preserves the welded connection therebetween.
  • Figure 1 illustrates a cell 1 of a type that has both a positive terminal and a negative terminal at one and the same end 2a (the top end in figure 1 ) of the cylindrical secondary cell 1 .
  • the first enclosure end 2a comprises a central terminal through-hole for the positive terminal.
  • the negative terminal is electrically connected to the cylindrical enclosure 2. More precisely, the negative terminal is formed by the top surface of the cylindrical enclosure 2 that surrounds the terminal through-hole. Thus, the entire cylindrical enclosure 2 (apart from the positive terminal at the top end) may be the negative terminal.
  • a cell 1 having both terminals at one end may bring advantages as regards electrically connecting the cell to a load. Conductors electrically connecting the terminals to the load may be positioned on the same end, the terminal end (top side in figure 1 ), of the cell.
  • the opposite end, which may be referred to as the electrolyte-filling end (bottom end in figure 1 ), of the cell 1 may be dedicated to electrolyte filling and venting.
  • An overpressure may be generated within the cell during operation, in particular upon malfunction of the cell or of the load connected to the cell. Such malfunction may require a release of gas and/or other ejecta out of the cell, and it may be advantageous to direct the released gas and/or other ejecta away from the conductors, i.e. at the end opposite to the terminal end.
  • a number of cells 1 may be positioned at a low position in an electric vehicle.
  • the cells 1 may be arranged with the terminal ends directed upwards and the electrolyte-filling ends (bottom end 2b in figure 1 ) directed downwards.
  • a release of gas and/or other ejecta from the electrolyte-filling end(s) will be advantageously directed downwards towards the ground beneath the vehicle.
  • the electrolyte-filling ends may be directed towards a desired location such that any gas and/or other ejecta will not cause damages or injuries.
  • the material thickness of the cell 1 and the lid 10 have been exaggerated to elucidate the features of the present disclosure.
  • the figures illustrate a certain gap between the cylindrical enclosure 2, the current collector disc 24, and the lid 10.
  • the lid 10 will be brought in direct contact with the cylindrical enclosure 2 (in particular the flange 2f) before attachment, i.e., by welding.
  • the flat flange section 2f has a thickness equal to the thickness of the enclosure sidewall 2c.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Connection Of Batteries Or Terminals (AREA)

Abstract

La présente divulgation concerne une cellule secondaire cylindrique (1) comprenant une enceinte cylindrique (2) comprenant une première extrémité d'enceinte (2a), une seconde extrémité d'enceinte (2b) et une paroi latérale d'enceinte (2c) s'étendant entre les extrémités d'enceinte (2a, 2b), au moins une extrémité d'enceinte (2b) étant ouverte. La cellule comprend en outre un rouleau d'électrode (20), un couvercle (10) et un disque collecteur de courant disposé entre le couvercle et le rouleau d'électrode (20) et en contact électrique direct avec le rouleau d'électrode (2). L'enceinte cylindrique (2) comprend une section de bride plate (2f) s'étendant à partir de la paroi latérale d'enceinte (2c) au niveau de l'extrémité d'enceinte ouverte (2b), et la partie radialement la plus à l'extérieur du couvercle (10) est conçue pour venir en butée et correspondre à la section de bride plate de l'enceinte cylindrique, et est soudée à ladite section de bride plate (2f).
PCT/EP2023/087089 2022-12-23 2023-12-20 Cellule secondaire WO2024133554A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
SE2251579A SE546105C2 (en) 2022-08-31 2022-12-23 A cylindrical secondary cell and a manufacturing method
SE2251579-5 2022-12-23
SE2350846-8 2023-07-05
SE2350846A SE2350846A1 (en) 2022-08-31 2023-07-05 Secondary cell

Publications (1)

Publication Number Publication Date
WO2024133554A1 true WO2024133554A1 (fr) 2024-06-27

Family

ID=89508839

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2023/087089 WO2024133554A1 (fr) 2022-12-23 2023-12-20 Cellule secondaire

Country Status (1)

Country Link
WO (1) WO2024133554A1 (fr)

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