A battery

Abstract

The battery comprises a cup-shaped container (8) closed off by a lid comprising an inner conductive portion (1), an insulating portion (2) around the inner portion, and a peripheral conductive portion (3, 4) that is fixed to the upper edge of the container by a conductive and sealing connection. The container houses an electrode assembly (100) comprising alternately stacked electrodes of a first and second polarity. The electrodes are coupled together by interconnected tabs (13, 12). A non-coated side of an electrode (11'') of the second polarity is connected to the base (40) of the container. A top insulating sheet (18) lies on top of a conductive sheet (16, 32) that is connected to the tabs (13) of the first polarity type. The top insulating sheet is provided with an opening (19), thereby exposing a portion of the conductive sheet. This exposed portion is electrically connected to the inner portion (1) of the lid. Said inner portion thereby forms the first polarity contact of the battery, while at least the base of the container forms the second polarity contact.

Description

A BATTERYField of the Invention

[0001] The present invention is related to batteries, e.g. button batteries, which are well-known as power sources for small electrically driven implements such as watches, thermometers or the like.State of the art.

[0002] Batteries, e.g. button batteries, which are also known as button cells, are widely used and available in a plurality of types, distinguished by various dimensions and shapes and by the materials used for the electrodes and the electrolyte.

[0003] Most known types of button batteries include a metallic bottom cup having a flat base portion that serves as the positive contact, an upstanding sidewall which extends upwards from the flat portion, and a metallic top lid cup. The flat base portion of the lid cup serves as the negative contact. The battery further includes an electrode assembly in the space between the top and bottom cup. In a rechargeable lithium-ion button battery for example, the electrode assembly may be a spiral-shaped assembly obtained by rolling up a stack of electrode layers separated by separator sheets impregnated with a liquid electrolyte. Other electrode assemblies are formed as horizontal stacks of alternately stacked electrode and separator layers oriented parallel to the top and bottom contacts. Button cells are often shaped as round discs but other shapes are possible as well.

[0004] The production process of the above-described battery type includes arranging the electrode assembly into the top lid cup and inserting the lid cup into the bottom cup with a gasket or glue-type electrically insulating sealing in between the two for sealing off the electrode assembly from the exterior of the battery. If a physical gasket is used, the open end of the wall of the lid cup is inserted into the gasket and the bottom cup is crimped overthe gasket. If a glue-type insulating seal is used, the outside of the sidewall of the top lid cup is coated with the sealing material, after which the top lid cup is inserted into the bottom cup. The glue is allowed to dry or cure, thus sealing the battery.

[0005] These known ways of sealing the batteries present a number of drawbacks. One problem is for example the double-wall configuration needed to accommodate either the gasket or the glue : the sidewalls of the top lid cup and the bottom cup must overlap against each other. This results in wasted space that is occupied by the insulating seal, either as a physical gasket or as the sealing glue.

[0006] A solution to this problem was found in the form of an improved battery design. The battery still comprises a bottom cup that contains the electrode assembly, and that still acts as the positive contact. The battery further comprises a lid formed of three portions: an electrically conductive inner portion, an electrically conductive peripheral portion and an electrically insulating intermediate portion that separates and insulates the inner portion from the peripheral portion. The inner portion acts as the negative contact and the insulating portion realizes the electrical insulation. The lid is fixed to the open end of the cup, thereby sealing off the battery from the exterior. The fixed connection of the lid to the cup is electrically conductive so that the positive contact comprises the base and sidewalls of the cup and the peripheral portion of the lid. The peripheral lid portion may consist of a first and second part

[0007] Combining containers of the latter type with a stacked electrode assembly is challenging in terms of obtaining reliable connections between the positive and negative current collectors of the assembly and the battery contacts. Another problem is related to the heating produced by the welding process for fixing the lid to the container. If the heat is confined to the welding area, it may negatively affect the electrolyte, which can be detrimental to the battery performance.of the invention

[0008] The invention aims to provide an improved battery that does not suffer from the above-described drawback. This aim is achieved by a battery according to the appended claims. Throughout the description and the claims, the term ‘conductive’ is to be understood as ‘electrically conductive’. The term ‘insulating’ is to be understood as ‘electrically insulating’.

[0009] According to embodiments of the invention, the battery comprises a cup-shaped container closed off by a lid comprising an inner conductive portion, an insulating portion around the inner portion, and a peripheral conductive portion that is fixed to the upper edge of the container by a conductive and sealing connection. The container houses an electrode assembly comprising alternately stacked electrodes of a first and second polarity. The electrodes are coupled together by interconnected tabs. These tabs are however not directly connected to the battery contacts and preferably covered by insulating sleeves folded around the sides of the electrode assembly.

[0010] A non-coated side of an electrode of the second polarity is connected to the base of the container. A top insulating sheet lies on top of a conductive sheet that is connected to the tabs of the first polarity type. The top insulating sheet is provided with an opening, thereby exposing a portion of the conductive sheet. This exposed portion is electrically connected to the inner portion of the lid. Said inner portion thereby forms the first polarity contact of the battery, while at least the base of the container forms the second polarity contact.

[0011] This configuration facilitates the connection between the electrodes and the battery contacts during the assembly of the battery, and enables a design wherein a space is available between the electrode assembly and the lid, allowing a better heat removal during welding operations applied for closing the battery, and a better possibility for ‘breathing’ of the electrode stack inside the container.Brief description of the figures

[0012] Figure 1 illustrates a container and corresponding lid suitable for housing an electrode assembly according to embodiments of the invention.

[0013] Figure 2 is an exploded view of a stacked electrode assembly applicable in a battery according to an embodiment of the invention.

[0014] Figure 3 shows the electrode assembly of Figure 2, after the stacking of the various electrodes and other components, and prior to interconnecting the stacked tabs.

[0015] Figure 4 shows the electrode assembly, after interconnecting the stacked tabs.

[0016] Figures 5 and 6 are views from the top and bottom, of the electrode assembly of Figure 4, after applying insulating sleeves onto the interconnected tab stacks.

[0017] Figure 7 is a cross-section view of a battery according to an embodiment of the invention, including a stacked electrode assembly, but without showing the details of the electrode assembly.

[0018] Figures 8 and 9 shows two enlarged details of the battery crosssection of Figure 8, now including details of the stacked electrode assembly.

[0019] Figure 10 shows an alternative embodiment of a battery according to the invention.

[0020] Figures 11 and 12 are enlarged details of the battery cross-section shown in Figure 10.

[0021] Figure 13 another battery shape of a battery in accordance with an embodiment of the invention.

[0022] Figure 14 illustrates a battery wherein the inner lid portion is provided with a tab coupled to the electrode stack.

[0023] Figure 15 is an enlarged detail of the battery cross-section shown in Figure 14.Detailed description of preferred embodiments of the invention

[0024] Figure 1 illustrates a partially exploded view of a battery container of the above-described type, wherein an insulator is incorporated in the lid of the container. In this particular embodiment, the lid comprises an electrically conductive inner portion 1 , a ring-shaped intermediate insulating portion 2 and an electrically conductive peripheral portion 3, 4 consisting of two parts: the first part 3 is ring-shaped and insulated from the inner conductive portion 1 by the intermediate insulating portion 2 of the lid. The second part 4 is equally ring-shaped, having an inner circumference 5 and is fixed along said inner circumference 5 to the outer circumference 6 of the first part 3 by an electrically conductive and sealed connection. The second part 4 is then fixed along its outer circumference to the open end of a cup-shaped container 8, also by an electrically conductive and sealed connection. Said open end is the upper edge of the upstanding sidewall 41 of the container, said sidewall extending along the circumference of the base 40 of the container. The two- part design of the peripheral lid portion 3, 4 enables producing the combination of elements 1 , 2 and 3 as a standard circular assembly that can be combined with a peripheral lid portion 4 of any shape, i.e. not only ring- shaped, for producing battery containers of any shape. As stated, this type of battery container is known as such in the prior art. The invention is however also applicable in combination with containers wherein the parts 3 and 4 form a single integral lid portion. The intermediate insulating portion 2 is fixed to the inner portion 1 and the first part 3 of the peripheral portion. The insulating portion 2 could be formed of glass, ceramic or polymer material, as known in the art.

[0025] Figure 2 is an exploded view of an electrode assembly 100 adapted to a container of the type illustrated in Figure 1 , in accordance with an embodiment of the invention. The assembly comprises a number of anodes and cathodes, which are alternately stacked, with separator sheets between adjacent electrodes of different polarities. In a manner known in theart, the cathodes are fitted in separator sheet pockets 10, i.e. two separator sheets on either side of the cathode and attached together along the circumference of the cathode. The assembly is thus formed by alternately stacking the anodes 11 and the cathode-containing pockets 10. Both electrode types comprise a metal foil portion with an active coating on one or both sides of the foil portion. All the cathodes in the pockets 10 are coated on both sides. The anodes 11’, 11 ” at the bottom and the top of the stack are coated on one side only, with the non-coated side respectively oriented away from the stack (as will be described in more detail later). All electrodes comprise a non-coated tab extending away from the coated electrodes. The tabs may be integrally formed with the foil portions of the electrodes. The anode tabs 12 are mutually aligned on one side of the stack while the cathode tabs 13 (which stick out of the separator pockets 10), are mutually aligned on the opposite side of the stack.

[0026] The features of the stack described so far are in accordance with known stacked electrode assemblies, for example as described in patent publication document EP3748710, describing an electrode assembly adapted to be fitted in a casing comprising a bottom and top cup separated by a gasket, as described in the introduction.

[0027] A number of alterations have been made to the prior art assembly: on top of the upper non-coated anode 11 ”, an insulating sheet 15 is placed, followed by a conductive sheet 16, for example an aluminium sheet. The latter has a similar shape as the anodes and cathodes, and comprises a tab 17 that is aligned to the cathode tabs 13. Above the conductive sheet 16 is a second insulating sheet 18 comprising a central opening 19. Both insulating sheets 15 and 18 comprise four wing portions 20, for holding the stack together, as known in the art and illustrated hereafter in more detail. Two insulating sleeves 21 are provided, whose function will also be described. Insulating sheet 15 will hereafter be referred to as the intermediate insulating sheet, while sheet 18 will be referred to as the top insulating sheet, as it will form thetop layer of the electrode assembly when it is mounted in a battery housing oriented horizontally.

[0028] The assembly of the components shown in Figure 2 takes place in a similar way as in the prior art: the anodes 11 and cathode-containing pockets 10 are stacked and the anode tabs 12 are aligned on one side of the stack while the cathode tabs 13 together with the tab 17 of the conductive sheet 16 are aligned on the opposite side, as shown in Figure 3. The superposed wing portions 20 of the intermediate and top insulating sheets 15, 18 are folded around the sides of the stack and onto the exposed surface of the bottom anode 1 T. The insulating sheets 15 and 18 including the wing portions 20 may be adhesive on one side to facilitate attaching the wing portions 20. The wing portions 20 thereby serve to hold the stacked electrodes together. As in the prior art stack, the anodes and cathode pockets are preferably provided with straight side edges at the location of the wing portions 20, to facilitate the folding of the wing portions at these locations. The insulating sheets 15, 18 could be formed of a plastic adhesive material such as Kapton tape, and should be compatible electrochemically with the electrolyte of the battery. The material is preferably thin and flexible to enable the use of the wing portions 20. The invention is however not limited to embodiments comprising these wing portions, and one or both of the insulating sheets 15, 18 could be formed of a less flexible material (without wing portions), such as a ceramic layer.

[0029] In a manner also known as such in the art, the stacked tabs (anode tabs 12 and cathode tabs 13 + tab 17) are pressed together and attached to each other by a welding process, to form two current collectors 24, 25 extending on either side of the stack, as illustrated in Figure 4. In prior art battery designs, these current collectors are connected directly or through additional tabs to the contacts of the battery housing. This is however not the case in a battery according to the invention.

[0030] Figures 5 and 6 show images of the assembled electrode stack 100 as seen from the top down (Figure 5) and from the bottom up (Figure 6).

[0031] It is seen that according to the illustrated embodiment, the current collectors 24, 25 are enveloped by the respective insulating sleeves 21 which are folded onto the top and bottom of the stack. The sleeves 21 may be adhesive on one side so that they stick to the sides and surfaces of the stack. This is to avoid direct contact between the current collectors and the container.

[0032] In Figure 5, the top insulating sheet 18 is shown in transparent view, so that the shape of the conductive sheet 16 is visible. The sheet is somewhat smaller than the electrodes and fits within the footprint of the stacked electrodes. This is a preferred arrangement without however limiting the scope of the invention. The central opening 19 in the top insulating sheet 18 exposes a central portion of the conductive sheet 16. This portion is configured to be connected to one of the contacts of the battery, as explained hereafter.

[0033] Figure 7 is a cross-section of a battery in accordance with an embodiment of the invention. The electrode assembly 100 is in accordance with Figures 5 and 6, but no details of the assembly are shown in Figure 7. Relevant details are however illustrated in the enlarged views of the rectangles 30 and 31 in Figures 8 and 9 respectively. Figures 8 and 9 also show the various components of the electrode stack in some detail: the cathode foil portions 32 and cathode coatings 33 on both sides of the foil, the separator sheets 34 forming a pocket 10 containing the 2-side coated cathodes. Between two such pockets 10 lies an anode 11 formed of a foil portion 35 with coating 36 on both sides. The bottom anode 1 T is however coated on one side only, and the non-coated side of the foil portion 35 of this bottom anode is in direct contact with the base 40 of the container. As all the anode tabs 12 are interconnected in the anode tab stack, the cup 8 along with the lid portions 3, 4 thereby form the negative contact of the assembledbattery. In practice, only the base of the cup 8 is used as a battery contact, and preferably the sidewalls are isolated from the exterior by an insulating layer, as described further in this description.

[0034] With reference again to Figure 7, it is seen that the battery housing itself is largely in accordance with the design shown in Figure 1 , the lid comprising an inner conductive portion 1 , an insulating portion 2 and a peripheral conductive portion 3, 4, the latter comprising a first and second part (3, 4). Step-shaped connections are made between the second part 4 and the rim of the cup 8 and between the first and second parts 3, 4 of the peripheral conductive portion. This step-shape facilitates the welding process used for assembling these parts by an electrically conductive and sealing connection. Contrary to most prior art batteries using this type of container, it is seen that the inner conductive portion 1 of the lid has a higher thickness than usual, and extends down into the interior of the container, and that this inner conductive portion 1 is in direct contact with the electrode assembly 100.

[0035] This connection is shown in detail in Figure 9. This figure shows in detail the top layers of the assembly 100 as described above: the intermediate insulating sheet 15, the conductive sheet 16, the top insulating sheet 18 with the central opening 19 therein. The diameter of the inner conductive lid portion 1 is adapted to the diameter of the opening 19, so that the inner conductive portion 1 fits into said opening 19, and thereby contacts the conductive sheet 16 directly. As the tab 17 of this sheet 16 is connected through the cathode tab stack to all the cathodes, these cathodes are thereby correctly connected to the positive contact of the battery, formed by the inner conductive portion 1 of the lid. The top anode 11 ” of the stack is also shown in Figure 9, comprising a foil portion 35 and a single coating 36. Underneath this top electrode lies the sequence of cathode-containing pockets 10 and anodes 11 , with foil portions, coatings and separator sheets numbered in the same way as in Figure 8.

[0036] It is seen in Figure 7 that this design leaves a considerable space 46 between the peripheral conductive portion 3, 4 of the lid and the top of the assembly 100. This space is filled with electrolyte prior to welding the lid to the cup. The space 46 enables a better distribution of heat generated by the welding process, while also allowing the electrode stack to ‘breath’, i.e. expand and contract, during the life of the battery.

[0037] According to an embodiment, illustrated in Figure 10, a highly conductive layer 50 is added between the base of the container 8 and the electrode assembly 100. This layer may extend up to the sidewalls of the container, as shown. However the layer 50 preferably does not extend to the upper rim of the sidewall, so that the layer does not interfere with the welding process for attaching the lid to said upper rim. The layer 50 is deposited on the inner surface of the cup prior to placing the electrode assembly 100 in the cup.

[0038] Preferably, a similar or the same type of layer 51 is added on the exposed portion of the conductive sheet 16, thereby improving the conductivity of the connection between the inner lid portion 1 and said conductive sheet 16. Figures 11 and 12 show these conductive layers 50 and 51 in more detail. These layers 50 and 51 are made visible in the drawings, but in reality the thickness of these layers may be so small as to be indistinguishable at the scale of the illustrated drawings.

[0039] Both conductive layers 50, 51 are electrochemically compatible with the electrolyte during the battery lifetime. Suitable materials for these layers include gold, nickel or carbon-based materials such as graphene or carbon nanotubes.

[0040] According to a further embodiment, an insulating layer 52 is applied to the outer surface of the sidewall of the cup 8, as also illustrated in Figure 10. This is beneficial in that it inhibits unwanted direct contact between the negative contact of the battery and external components.

[0041] Layers 50, 51 and 52 are preferably all applied together, as in the illustrated embodiment shown in Figure 10. However, embodiments wherein only one or two of these layers are applied are also included in the scope of the invention.

[0042] An alternative embodiment is illustrated in Figure 13. The image shows only the region where the inner conductive portion 1 of the lid contacts the electrode assembly. The region where the assembly contacts the base of the container is the same as shown in Figure 8, i.e. foil portion 35 of the bottom one-sided anode 1 T directly contacts the base 40 of the container. At the top of the assembly however, and again with reference to Figure 13, the top electrode is not a one-sided anode, but a one-sided cathode 45. This cathode 45 comprises a foil portion 32 and a coating 33, with the non-coated side of the foil portion 32 oriented towards the inner lid portion 1 . The cathode 45 is not enclosed in a separator pocket 10 as in the previous embodiments, but it is separated from the adjacent anode 11 by a single separator sheet 46. Like the other cathodes of the stack, the top cathode 45 comprises a tab (not shown) aligned to the other tabs 13 (as in Figure 2) of the cathodes, and the tab stack is connected together by a welding or similar process. The top insulating sheet 18 comprising a central opening 19 is now lying directly on the foil portion 32 of the one-side coated top cathode 45, and the inner conductive portion 1 of the lid is in direct contact with said cathode foil portion 32 through the central opening 19 of the insulating sheet 18. So in this embodiment, there is no intermediate insulating sheet 15, only the top insulating sheet 18, while the foil portion 32 of the top cathode 45 constitutes (i.e. plays the part of or is equivalent to) the conductive sheet 16 in the previous embodiment. This embodiment can be combined with one or both of the conductive coatings 50, 51 and with the insulating coating 52 illustrated in Figure 10.

[0043] According to yet another embodiment, the top electrode of the assembly is a two-side coated cathode 32, 33 enveloped by two separatorsheets 34. The conductive sheet 16 could then be placed directly on the upper of these two separator sheets 34 with the top insulating sheet 18 directly on the conductive sheet 16. Said upper separator sheet 34 in this case plays the part of the intermediate insulating sheet 15 of the embodiment of Figure 9.

[0044] The invention is not limited to containers as shown in Figure 1 , i.e. with the peripheral conductive portion of the lid consisting of two parts 3, 4. Embodiments of the invention are possible with a container wherein the peripheral conductive portion is a single uniform piece.

[0045] The invention is not limited to cylindrical batteries. Any battery shape of a planar battery can be produced, for example by combining the assembly of the elements 1 , 2, 3 in Figure 1 with a cup and second conductive part 4 of corresponding shapes. An example is shown in Figure 14, showing a top view and cross section of a battery having a rectangular shape. The assembly 1 , 2, 3 is in an out-of-center position of the lid. The second part 4 of the peripheral conductive lid portion 3, 4 now has a rectangular outer rim, that fits onto the corresponding upper edge of the rectangular cup 8. The electrode stack 100 is shaped accordingly to fit into the cup. The opening 19 in the top insulating sheet 18 is located in accordance with the out-of-center location of the inner conductive portion 1 .

[0046] According to another embodiment illustrated in Figures 15 and 16, the inner conductive portion 1 of the lid does not extend into the interior of the container, but a contact tab 55 is attached to the inner conductive portion 1 . The contact tab is welded to the conductive sheet 16 at the location of the opening 19 in the top insulating sheet 18. This embodiment can be combined with one or both of the conductive coatings 50, 51 and with the insulating coating 52 illustrated in Figure 10. The contact tab 55 can also be combined with the embodiment illustrated in Figure 13.

[0047] According to a further embodiment, a conductive tab (not shown) may be connected between the non-coated side of the foil portion 35 of the bottom electrode 1 T of the electrode stack and the base 40 of the container.The tab may be welded to the foil portion 35 and to the base of the container (possibly provided with the highly conductive layer 50). The tab establishes an electrical connection, in addition to or in replacement of the direct contact between the foil portion 35 and the base 40 of the container. The tab also makes sure that the stack is physically attached to the base of the container, to thereby avoid shifting of the stack relative to said base of the container.

[0048] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

Claims

CLAIMS1 . A battery comprising:- a cup-shaped container (8) containing an electrode assembly (100) and an electrolyte, the container comprising a base (40) and an upstanding sidewall (41 ) along an outer circumference of the base, said base and sidewall defining an inner space of the container,- a lid comprising• an inner electrically conductive portion (1 ),• an intermediate insulating portion (2) surrounding the inner conductive portion (1 ),• a peripheral electrically conductive portion (3, 4) electrically isolated from the inner portion (1 ) by the intermediate insulating portion (2), wherein:- the outer edge of the peripheral conductive portion (3, 4) is fixed to the upper rim of said upstanding wall (41 ), by an electrically conductive connection that seals the interior of the battery from the environment,- the inner electrically conductive portion (1 ) forms a contact of a first polarity type of the battery and at least the base (40) of the container (8) forms a contact of a second polarity type of the battery,- the electrode assembly (100) comprises a stack of electrodes of the first and second polarity type stacked alternately with separator sheets between adjacent electrodes of different polarity,- each electrode comprises a coated electrode portion (32, 33 ; 35, 36) and a non-coated tab (13, 12) extending outward from the coated electrode portion, wherein the tabs ofelectrodes of the first polarity type are electrically interconnected in a first tab stack and the tabs of the electrodes of the second polarity type are electrically interconnected in a second tab stack,- the bottom electrode (11’) of the electrode stack is a second polarity type electrode comprising a foil portion (35) coated on one side only wherein the non-coated side of the foil portion (35) is connected to the base (40) of the container (8) or to an electrically conductive layer (50) present on said base of the container,- the electrode assembly (100) comprises a top insulating sheet (18) at the top of the assembly, said insulating sheet lying on top of an electrically conductive sheet (16, 32) that is electrically connected to the first tab stack, which interconnects the tabs (13) of the electrodes of the first polarity type,- the top insulating sheet (18) comprises an opening (19) through which a portion of the conductive sheet (16, 32) is exposed,- said exposed portion of the conductive sheet (16, 32) is electrically connected to the inner conductive portion (1 ) of the lid.

2. A battery according to claim 1 , wherein the inner conductive portion (1 ) of the lid directly contacts said exposed portion of the conductive sheet (16, 32), or directly contacts an electrically conductive layer (51 ) present on said exposed portion.

3. A battery according to claim 2, wherein the inner conductive portion (1 ) of the lid is thicker than the peripheral conductive portion (3, 4) of the lid and extends down into the inner space of the container.

4. A battery according to claim 2, wherein a conductive tab (55) is coupled between the inner conductive portion (1 ) of the lid and the exposed portion of the conductive sheet (16) or between the inner conductiveportion (1 ) of the lid and an electrically conductive layer (51 ) present on said exposed portion.

5. A battery according to any one of the preceding claims, wherein the top insulating sheet (18) comprises wing portions (20) which envelop respective side portions of the stack.

6. A battery according to any one of the preceding claims, wherein the top electrode (11”) is an electrode of the second polarity type, comprising a foil portion (35) coated on one side only, the non-coated side being oriented towards the lid, wherein the assembly comprises an intermediate insulating sheet (15) inserted between the top electrode (11 ”) and the conductive sheet (16), and wherein said intermediate insulating sheet (15) isolates the top electrode (11 ”) from the conductive sheet (16).

7. A battery according to claim 6, wherein the conductive sheet (16) comprises a tab (17) aligned to the tabs (13) of the electrodes of the first polarity type, and wherein said tab (17) of the conductive sheet (16) is part of the first tab stack and thereby electrically connected to the tabs (13) of the first polarity type.

8. A battery according to claim 6 or 7, wherein the intermediate insulating sheet (15) comprises wing portions (20) which envelop respective side portions of the stack.

9. A battery according to any one of claims 1 to 5, wherein the top electrode (45) is an electrode of the first polarity type comprising a foil portion (32) coated on one side only, the non-coated side being oriented towards the lid, and wherein said foil portion (32) of the top electrode constitutes said conductive sheet.

10. A battery according to any one of the preceding claims, wherein the first and second tab stacks are enveloped by respective insulating sleeves (21 ) folded around opposite sides of the electrode assembly (100).

11. A battery according to any one of the preceding claims, comprising an electrically insulating layer (52) on the outer sidewall (41 ) of the cupshaped container (8)12. A battery according to any one of the preceding claims, wherein the peripheral electrically conductive portion of the lid is formed of a first part (3) having an outer circumference (6), the first part being insulated from the inner conductive portion (1 ) by the intermediate insulating portion (2) of the lid, and a second part (4) having an inner circumference (5), the second part being fixed along said inner circumference (5) to the outer circumference (6) of the first part (3) by an electrically conductive and sealed connection.

13. A battery according to any one of the preceding claims, wherein the noncoated side of the foil portion (35) of the bottom electrode (11’) is in direct contact with the base (40) of the container (8) or with an electrically conductive layer (50) present on said base of the container.

14. A battery according to any one of claims 1 to 13, wherein a conductive tab is connected between the non-coated side of the foil portion (35) of the bottom electrode (11’) and the base (40) of the container (8) or between said non-coated side of the foil portion (35) of the bottom electrode (11’) and an electrically conductive layer (50) present on said base of the container.

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