AN ELECTRODE AND A METHOD OF PROVIDING AN ELECTRODE AND A BATTERY LAMINATE

Abstract

An electrode, a battery laminate, a battery and methods of providing the electrode, laminate or battery, where the electrode has an electrode layer and a current collector both having through-going bores of a size allowing liquid transport through the current collector and the electrode layer. The bores are provided by providing elongate slits or weakened portions and deforming the electrode. The current collector also has channels therein allowing liquid to travel along a plane of the current collector. In this manner, the drying of and introduction of electrolyte therein is made much faster.

Claims

1.-18. (canceled)

19. An electrode, such as for a battery, the electrode comprising: a current collector having a first and a second main surfaces, a first layer of a first electrically conductive material provided at or on the first main surface, and where the current collector comprises a plurality of slits, having a length of at least 2 μm, the laminate being deformed to provide the slits with a width of at least 2 μm.

20. The electrode according to claim 19, further comprising a second layer of a second electrode material provided at or on the second main surface, the slits of the deformed laminate extending through the second layer.

21. The electrode according to claim 19, wherein the deformed current collector defines a plurality of portions each defining a direction being at an angle of at least 5 degrees to a central plane of the current collector.

22. The electrode according to claim 19, wherein the slits comprise a plurality of at least substantially parallel slits.

23. The electrode according to claim 19, which has a plurality of portions extending at an angle which is least 10 degrees from a mean plane of the current collector.

24. A battery laminate comprising a first electrode according to claim 19, a second electrode and a separator layer provided between the first and second electrodes.

25. The battery laminate according to claim 24, wherein the second electrode is an electrode.

26. The battery comprising a battery laminate according to claim 24.

27. The battery laminate according to claim 24, further comprising a fluid provided between the current collector and the first and second electrode layers as well as in the slits.

28. A method of providing an electrode the method comprising: providing a current collector having a first and a second main surfaces, where: at or on the first main surface, a first layer of a first electrically conductive material is provided, providing, in the current collector, a plurality of weakened portions, further comprising the step of deforming the current collector to form, at the weakened portions, slits with a length of at least 2 μm and width of at least 2 μm.

29. The method according to claim 28, wherein the deformation causes the current collector to define a plurality of portions each defining a direction being at an angle of at least 5 degrees to a central plane of the current collector.

30. The method according to claim 28, further comprising the step of providing, at or on the second main surface, a second layer of a second electrode material, the second layer comprises a third plurality of through-going bores each having a cross section with a shortest distance of at least 2 μm.

31. The method according to claim 28, wherein the step of providing the slits comprises providing a plurality of at least substantially parallel slits.

32. The method according to claims 28, wherein the deformation step comprises a step of stretching the current collector.

33. The method according to claim 31, wherein the deformation step comprises a step of stretching the current collector and wherein the stretching is along a direction at an angle to a direction of the slits.

34. The method of providing a battery laminate, the method comprising: providing a first electrode according to claim 28, where the electrode material is an anode material, providing a second electrode, where the electrode material is a cathode material, and providing a separator between the first and second electrodes.

35. The method of providing a battery laminate, the method comprising: providing a first electrode according to claim 19, where the electrode material is an anode material, providing a second electrode, where the electrode material is a cathode material, and providing a separator between the first and second electrodes.

36. The method according to claim 34, further comprising the steps of: rolling and/or folding the battery laminate, drying the rolled/folded laminate, providing the dried laminate in a container and adding a fluid to the laminate in the container.

37. A battery according to claim 25, further comprising a fluid provided between the current collector and the first and second electrode layers as well as in the slits.

38. A method according to claim 35, further comprising the steps of: rolling and/or folding the battery laminate, drying the rolled/folded laminate, providing the dried laminate in a container and adding a fluid to the laminate in the container.

Description

[0129] In the following, preferred embodiments are described with reference to the drawing, wherein:

[0130] FIG. 1 illustrates a cross sectional and exploded view of an electrode according to the invention,

[0131] FIG. 2 illustrates a first manner of providing a 3D structure of a current collector,

[0132] FIG. 3 illustrates a second manner of providing a 3D structure of a current collector,

[0133] FIG. 4 illustrates a rolled battery laminate,

[0134] FIG. 5 illustrates a laminate with a varying thickness,

[0135] FIG. 6 illustrates a jelly roll laminate combed and connected to a cap and

[0136] FIG. 7 illustrate a jelly roll with both current collectors connected to a single cap.

[0137] FIG. 8 illustrate an electrode laminate before and after final calendaring.

[0138] In FIG. 1, an electrode laminate 10 is illustrated comprising a central current collector 12, a first electrode layer 14 and a second electrode layer 16. One electrode layer suffices, but two are preferred especially when combined (see below) with, but separated by, a separator from another electrode laminate to form a battery structure. A battery laminate is usually provided by two such electrode laminates where the electrode materials are selected suitably in the galvanic table. Often, aluminium is used as a cathode current collector and cupper is used as an anode current collector in batteries.

[0139] In the current collector 12, a through-going bore or slit 124 is seen. This bore/slit 124 has a size large enough to allow liquid or fluid transport there through. After deformation of the current collector, the slit 124 has a minimum size of 2 μm, but larger sizes will allow faster liquid transport. The size of the bore may be that of the bore when projected on to a plane perpendicular to a direction of the bore or the direction of liquid flowing through the bore. Naturally, a slit may be meandering, so that the size of the bore may vary along the bore.

[0140] This slit may be provided in a number of manners, some of which are described below. Less preferred manners are e.g. laser cutting or ablation, as this both removes material from the current collector and leaves the current collector completely flat as it was flat before the cutting. Below, however, is described a manner of converting a plane layer to a very useful 3D shaped element.

[0141] The current collectors are thus completely embedded in the electrode material and there is also electrode material in the openings of the current collector. The effect of electrode material connection through the current collectors is that the capillary liquid transport is improved and that the current collector and the electrode material connection becomes stronger and thus less likely to delaminate.

[0142] The two electrode layers also comprise through-going bores 142 and 162, respectively. These bores, as the slits, have dimensions allowing liquid or fluid transport there through.

[0143] Clearly, the laminate may have any length and any density and position, symmetrical or not, ordered or stochastic, of the slits 124 and bores 142/162.

[0144] In addition to the slits 124, the current collector comprises a channel-forming structure 130 (see FIG. 3) allowing liquid transport also generally along the direction or in the plane of the current collector. This may be obtained in a number of manners. In one situation, the current collector is or comprises a woven or nonwoven material allowing liquid transport both across the thickness thereof as well as in the plane thereof.

[0145] Other types of current collectors may be formed by initially non-permeable or non-porous layers, such as solid layers, in which holes/channels are made. Clearly, any material, porous/permeable or not, may be used now that the holes/channels are generated. It is noted that the liquid transport in or along the plane of the current collector may be obtained by making the current collector or the current collector material porous to the degree where liquid transport is facilitated. Alternatively, the current collector may be shaped or deformed to a degree where liquid transport is facilitated (see FIG. 3) along an outer surface thereof. This is described further below. The incisions seen in FIG. 3 may be varied in angles in order to create desired flexibility in different directions for the current collector.

[0146] The advantages of the slits 124 and bores 142 and 162 and the channels 130 is that they allow liquid transport through the layers and along/in the current collector so that the laminate may be dried swiftly and even if rolled into a roll as seen in FIG. 4 before drying. Any liquid or fluid remaining in the laminate may be allowed to escape via the channels and bores so that the laminate may be dried. Alternatively, the laminate may be added liquid or fluid also when rolled, as this liquid/fluid may find its way through the slits/bores and along the layers so that all or almost all spaces between the layers may be filled with liquid/fluid.

[0147] Most batteries today are slurry based in the sense that a liquid solution is used during the production process. Most of these liquids used for preparing battery slurries are toxic hazardous volatile organic compounds and create environmental and health hazardous conditions. For these reasons and because the fumes are explosive the slurry drying also involves a condensation and recycling process, which is the single most energy consuming process in battery production. The electrolyte is added to the rolled laminate in order to obtain the ion transport needed for proper battery functionality. The bores will vastly reduce the time required for the electrolyte to completely wet the laminate. Similarly, the formation process involving the creation of the SEI (Solid Electrolyte Interphase) can be performed significantly faster due to the freer flow of electrolyte and the ions within them because the ions can travel through channels with less tortuosity. The electrolytes used can be any commonly used electrolytes including liquid, polymeric and ceramic electrolytes.

[0148] As mentioned above, the current collector is provided so that liquid may more easily travel along the outer surface of the current collector and/or within the current collector.

[0149] The function of the channel(s) is to allow liquid travel, as well as ion travel, from a bore 162 through a slit 124 and further to a bore 142 or vice versa. Thus, the channels provide, with the bores, liquid and/or ion transport across the laminate.

[0150] Naturally, the manner of providing the slits 124 and the manner of obtaining the channels may be independent of each other, but the two properties may be achieved in the same process.

[0151] The channels may, as mentioned above, be defined by providing the current collector as a porous material. A porous material may be made of e.g. particles, fibres or the like allowing liquid transport in all or many directions.

[0152] Alternatively, the current collector may be made of any material, such as a non-porous material or a material with a too low porosity or pore size, where the current collector material is then provided with a 3D structure allowing the liquid transport. In FIG. 3, a structure is seen where a bore slit is formed by e.g. forcing a needle or other element through the current collector material which then both forms the bore 124 but is also forced outwardly (upwardly). Clearly, when the electrode layer 162 is provided at or on the surface of this current collector, the electrode layer will abut a surface 126 defined by the outwardly flaring portions around the slits 124. Then, liquid may travel in and/or along the current collector in the space of channel 130 defined between the current collector material and the electrode layer.

[0153] In FIG. 2, another manner of providing a 3D structure of a current collector material is seen. A number of more or less parallel cuts 125 are made in the current collector, which again may have any porosity, such as no porosity. When pulling the upper and lower surfaces (in FIG. 2) away from each other, the current collector will obtain a shape where openings or slits 124 are generated at the cuts 125 and where portions of the current collector will be flaring or directed upwardly and others downwardly. Naturally, the cuts 125 may be through going or extend only partly through the material. The pulling may break the weakened portions at the cuts. The portions between the cuts 125 then will obtain different angles to the plane of the current collector before pulling/deformation.

[0154] Clearly, the cuts 125 may be made only in the polymer layer 121, if this is a laminate as described below, such as prior to the providing of the conducting layers 122 and 123, as the layers 122 and 123 usually will be so thin, such as 1-10 μm, such as 2-5 μm, such as about 2 μm, that they will not be able to keep the cuts 125 closed but will break and thus form the bores 124. The scoring or cuts 125 may be provided by feeding the laminate (or the layer 121) between two rollers whereof at least one roller has a number of knives performing the desired cuts. Alternatively, the laminate (or the layer 121) may be fed through a needle printer, such as a piezo electrically driven needle printer, which is configured to perform the cuts desired in highly accurate repeatable patterns using needles that have the specific forms and orientation best adapted to create the desired porosity while preserving the optimum electric and thermal conductivity.

[0155] Alternatively, the layers 122/3 may be applied to the material 121 when stretched.

[0156] Alternatively, the laminate or sheet can be fed through two rollers along with random sharp, hard particles that punch through or weaken the sheet at random positions and perhaps also roughen the surface not punched through. The punched-through holes then again facilitate liquid transport and the roughened surface will define an outer surface engaged by the electrode and a space between the current collector surface and the electrode surface along which liquid may travel.

[0157] The pulling is preferably substantially along a direction at an angle to that of the cuts. Cuts may be provided with different angles (see cut 125′) to the direction of pulling, and pulling may be performed along multiple directions, such as along directions at an angle, such as perpendicular, to each other.

[0158] All these alternative processes are possible to adapt for high speed roll to roll processing as they are general for printing or embossing of webs passed through roll to roll processing and as such can be performed at great speeds.

[0159] Again, a current collector is formed having an outer surface defined by the outwardly flaring portions and where the electrode layers are brought to abut these surfaces and also connect through the punctured holes in the current collector. The current collector thus assumes a much thicker 3D shape than the actual current collector material, and the increased size gives rise to an internal porosity or channel forming allowing liquid transport not only perpendicular to the thickness or general plane of the current collector but also in a direction in the plane thereof. This internal structure additionally allows for a compressibility of the current collector which may be desired to take up any dimensional change of the electrode layer during charging/discharging.

[0160] The structured current collector may then be further altered before appending or attaching the electrode layer, the current collector may be slightly compressed to ensure that all outwardly directed portions thereof extend to a predetermined plane 126 to one or both sides, such as between parallel planes with a predetermined distance between them. Thus, when the outwardly directed portions are deformed or forced to adapt to a particular plane, these will form better electrical connections to the electrode material. Clearly, this deformation or altering will maintain at least part of the internal structure of the layer so that the liquid transport is possible.

[0161] The outer or main surface of the current collector thus is formed by the outwardly extending portions and any post processing these may be exposed to. This surface preferably is very open, so as to allow liquid transport into the current collector and between the two sides of electrode materials on both sides of the current collector and through it. Actually, the surface may be defined by a plurality of outwardly extending portions between which the liquid may flow.

[0162] In addition, the structural integrity of the connection between the metallic layer and the current collector core layer 121 can be enhanced by feeding the current collector core through a plasma process that nano roughens the surface prior to the deposition of the metallic layer. This will, combined with the physical deformation during the hole puncturing, increase the surface area of the current collector prior to the deposition of the anode metal or respectively the cathode metal layer. To further increase the connection between the current collector core and the added metal layer, the core itself can be made from a thermally and electrically conductive polymer such as polymers with a large proportion of graphene by wt %. Sputtering upon graphene filled polymer enhances the sputtered layers thermal, electric and mechanical attachment to the polymer core because the graphene flakes in the surface area upon the plasma treatment increase the surface area and embed the connection deeper into the core polymer than the polymer chains in the core material.

[0163] The outwardly extending portions may extend from a more central portion of the current collector. From this portion or such portions, which may be more plane without having to be completely plane, portions may extend in multiple directions so as to have portions extending toward both electrode layers if two are provided. The extending portions thus may be sheet-shaped or flat and may have any width and length.

[0164] The extending portions may be generated in any desired manner. Preferably, the extending portions extend from a central portion and are integral with it. The extending portions may be formed from an initial current collector element, such as a sheet, and caused extend from a plane of that portion or sheet. The above-mentioned drawing may be one manner of providing this extension or redirection. Another manner would be to permanently deform the extending portions, such as due to or during heating thereof.

[0165] When a portion extends from the central portion, the portion may leave an opening in the central portion, which opening then allows liquid flow through the current collector.

[0166] Naturally, if two electrode layers 14/16 are provided, the bore/slit forming structure may be performed from both sides of the current collector if such flaring portions are desired toward both electrode layers.

[0167] When the electrode material is provided at or on both sides of the layer or laminate, the electrode material may extend also through the bores/slits/channels of the layer or laminate. This may facilitate capillary liquid transportation such that drying once commenced will be completed to even dryness and similarly electrolyte filling also will be completed completely.

[0168] The current collector laminate may be manufactured in any desired manner, such as by depositing layers 122 and 123 on the layer 121 by lamination, sputtering, electro deposition or the like.

[0169] Clearly, the slits 124 and bores 142/162 need not be positioned as extensions of each other, as liquid or fluid may travel along the interface between the current collector and the anode/cathode, i.e. from a bore 162 to a slit 124 and further to a bore 142.

[0170] In FIG. 1, the electrode layers 14 and 16 are illustrated as laminates of a number of individual layers. The providing of the electrode layer as a laminate of a plurality of layers has a number of advantages.

[0171] One advantage is that the e.g. anode may now be provided as a laminate of layers with different properties and/or made by different process steps.

[0172] Such different properties can range from differences in porosity, difference in thermal conductivity, differences in electric conductivity, differences in charge holding properties and differences in particle size and shape, for example. The porosity differences in a 3D controlled electrode, such as an anode, can create electrolyte channels that increase the overall flow of e.g. Lithium ions while also creating denser areas where the thermal and/or electric conductivity is enhanced. The thermal and/or electric conductivity can also be enhanced by thin layers of metal alloys deposited by sputtering or plasma arch deposition and these layers may also comprise charge holding alloys, where Antimony based alloys are of particular interest and includes especially ZnSb, SnSb, CoSb and CuSb. Van der Waal forces are part of the forces that that hold the anode together and is impacted by the 3D shapes and sizes of the materials used. Long fibrous materials may hold the anode together with less usage of binder and may aid in the electric conductivity through larger anisotropic electric conductance.

[0173] As is described above, different layers may be provided with different materials, properties, porosity and the like. Different layers may be provided in different steps using different techniques if desired. In one situation, it is desired that the porosity of the electrode material decreases so that the porosity at the centre of the electrode material and at the current collector is high, so as to allow liquid transport. At the outer portions of the electrode material, the porosity may be adapted to other purposes such as a compromise between openness and the amount of material provided.

[0174] Preferably, however, the printing is performed so that the channels 162/142 are generated from the beginning. An alternative would be to provide the e.g. anode as a complete layer of the desired material and then provide the channels/bores by punching, laser ablation, cutting or the like. This providing of the channels/bores may break the integrity of the layer, as this layer preferably is quite thin. By providing the layer 14/16 by printing, no such working and thus no such risk is required.

[0175] In fact, another aspect of the invention relates to the above forming of an electrode as a number of, preferably at least substantially parallel, layers. Thus, the above advantages of the anode/cathode may be obtained. Naturally, in this aspect, the providing of the through-going bores 142/162 are only optional.

[0176] In FIG. 4, a wound or rolled-up laminate is seen. Clearly, an empty space will be seen at both the inner end of the laminate as well as at the outer end, when this cylindrical laminate is provided in a corresponding, cylindrical housing. It is desired to utilize all space in the housing. Thus, it is desired that the laminate is as thin as possible at least at the inner and outer ends, as this reduces the amount of space wasted.

[0177] On the other hand, the thickness of the laminate defines the loading capacity thereof, so a rather larger thickness is generally desired. In general, the thickness of the laminate scales more or less linearly with the loading capacity thereof, as the primary manner of reducing the thickness is the reduction of the thickness of the electrodes. Often, the current collector and the separator, which is usually provided between the anodes and cathodes of a battery, are not easily reduced in thickness.

[0178] A solution to this waste of space is seen in FIG. 5 where the outer ends of the laminate are made thinner so as to reduce the amount of space wasted while the majority of the length of the laminate has the desired thickness so that the desired loading capacity is obtained.

[0179] Naturally, a number of alternatives or additions may be used or utilized if desired. For example, as is known already, a PEDOT material or layer may be provided between the current collector, such as a woven/nonwoven or one or both layers 122/123, and the neighbouring anode/cathode. PEDOT materials are known for increasing electrical connectivity which is a sought-for advantage in batteries. Thus, the PEDOT material would form part of the current collector and thus also take part in forming the outer or main surfaces of the current collector.

[0180] A PEDOT layer also may reduce corrosion of the anode and cathode current collectors and thus increase the number of cycles the battery is able to obtain. PEDOT may fuse the electrode to the current collector and prevent separation from of the two, which both increase the Wh/kg, Wh/L and the charge and discharge characteristics of the battery. Further, the PEDOT layer may be viewed as part of the electrode as it can contain charge holding and electric conductive materials such as Carbon Fullerenes and in particular graphene for anodes and fluorographenes for cathodes.

[0181] In FIG. 6, a manner of providing a tab-less connection of an electrode with material layers 14 and 16 in a battery structure comprising another electrode with a current collector 22 and an anode/cathode material 141, separated by a separator 15. The left/lower side of the current collector 12 is connected to the cap 20. The outer electrode 22 may be contacted directly from the outer side thereof.

[0182] The ideal connection of a battery is along the entire length of the current collector because this in one and the same go provides the shortest thermal and electric pathways which consequently provides the least thermal and electric resistance. In a 18650 battery, 8 tabs are required to almost match the electric connection of a battery electrode in a coin cell. This impractical as the two tabs in an 18650 weigh 1% of the total weight and are costly to manufacture and connect. 8 tabs would increase the weight by 8% and cost about the same. Many problems in batteries arise from the tabs as the electric current from the current collector is routed through a thin tab that heat up and cause local early thermal damage to the battery electrodes nearby. Due to the resistance considerable Ohmic losses reduce the roundtrip efficiency of the batteries.

[0183] The embedded current collector connects electrically and thermally to the electrode along its entire area and extends out of the electrode as does the separator 15 that is inserted between the electrode materials 16/14 and 141. The connection to the cap 20 is made feasible by combing the extending separators and current collector to one side which create a spiral of current collector flanked by two spirals of separators one under underside of the current collector and one partly covering the current collector spiral. The separator extending on the underside of electrode material 14 ensures that there is no risk of short circuiting due to contact between the current collector 12 and the electrode material 141. Thus, the extent to which the separator 15 extends out of the laminate, i.e. compared to the electrode materials 16/14 and 141, so far that when bent to follow the underside of the laminate, it will cover the thickness of the material 141, thus preventing any contacting between the current collector 12 and the material 141 and the current collector 22. Now, the outwardly extending separator portions may be bent to one side, as may the outwardly extending current collector portions. As the separator portions are automatically positioned closer to the material 141, the separator portions will cover the material 141, so that the current collector portions 12 may extend as far as desired, and may all be contacted directly from below.

[0184] The exposed current collector 12 is exposed for connection to the cap by applying a conductive material. The conductive material not shown in the drawing can be chosen among several options such as low melting point solders such as SnSb alloys or conductive glues such as PEDOT. The solder can be pre coated upon the cap and activated by applying heat that liquefy the solder without harming the separators or the current collector or the cap. For lower solder fuse temperature a solder paste that is essentially powder metal solder suspended in a thick flux medium. The solder paste acts as a temporary adhesive, holding the components in place until the soldering process melts the solder and fuses the parts together. By use of flux the solder temperature can be decreased. Solder paste can be printed onto the cap or can be applied through holes in the cap not shown in the drawing. Connecting with PEDOT or other electrically conductive glues widely used in the electronics industry for SMD component can applied in the same ways as the solder paste only the glues usually are two component where the polymerization is induced by applying heat or UV radiation. For applying either UV or heat the holes in the cap are useful. Alternatively, the cap can be made from a UV transmissive material such as polymer or ceramics. As the cap function as a part of the thermal pathway transparent versions should be chosen among materials with good thermal conductivity such as par example diamond, diamond like carbon, Silicon Carbide. For electric conductivity the cap should be connected to a conductive material from where the conduction of current to the battery terminals. Alternatively, the cap can be made from opaque materials such as conductive materials as for instance metals like steel, aluminum, copper, titanium, nickel, lithium, silicium or alloys hereof. Clear many other metals could be used and alloys hereof but the sort after properties are lightweight easy solder and glue connection and low cost, so alloys involving aluminium are probably the go to solution. The issue with soldering on especially aluminum can be sorted by coating the metal cap design with a layer of copper or nickel which is a well-established practice in the electronics industry.

[0185] The FIG. 6 shows a connection of a battery with a U shaped laminate (Applicant's co-pending application PCT/EP2020/064868) but is equally useful for a design where the anode and cathode current collectors are folded and connected in each end of a jelly roll. And similarly if the laser shrinking is performed in register with the subsequent winding the anode and the cathode current collectors can connect to different areas of the same cap. Cutting a laminate with separators, anodes and cathodes will leave the anode and cathode equally protruding inside the separators, which will make connection challenging. The challenge can however be resolved by heat shrinking the cathode current collector or the anode current collector. For this process to function the heat shrink temperature has to be applied separately to either the anode current collector or the cathode current collector. This can be achieved by selecting the separator from materials that withstand heat such as non-woven aramid fiber separators combined with a focused laser heating that created the desired shrinking temperature in a specific depth. Additional the laser can be operated from the side where the current collector to be shrunk is closest and additionally the laser shrinking can be performed when the laminate is on a cooled roller and additionally the wave length of the laser can be tuned to be absorbed to a greater extend by either the anode current collector or the cathode current collector.

[0186] Two areas respectively for the anode and the cathode current collector connection will suffice but if so desired a multitude of connecting areas for both the anode current collector and the cathode current collector can be provided.

[0187] The flexibility of the current collector, which was introduced with the openings created for liquid flow through the current collector, ensures that when the ends of the separators and current collectors are combed to one side they will fold over each other and expose a spiral of current collector overlaying a layer of separator. The combing allows the addition of PEDOT or similar electric conductive glue that connect the entire length of the current collector to a conductive cap, which ensure as short as possible thermal and electric pathways.

[0188] In FIG. 7, a manner of providing a tab-less connection of the electrodes 16/14 and of another electrode formed by the material 141 and the current collector 22 (see FIG. 6) to the cap 20 via the current collector 12 of the electrode 16/14 and current collector 22 of the electrode material 141. FIG. 6 illustrates a connection of a battery with a U-shaped jelly roll laminate. For normal industry standard laminates, the solution can be cap systems in both ends. However, it is advantageous for many cells to keep the connection of both the anode and the cathode current collectors on the same side which is seen in FIG. 7.

[0189] A standard battery laminate comprises a separator, an anode, a separator, and a cathode. For the preferred roll to roll production it is advantageous to produce the complete laminate prior to winding it up and even more preferably before the laminate is not completely dried. This requires the general laminate to be separated into laminates for specific battery sizes such as coin cells, stacked pouch, stacked prismatic, jelly roll pouch, jelly roll prismatic and jelly roll cylindrical. This can be done one by one, before they are stacked to form the final laminate, but it is very advantageous to do the entire process at web level by stacking the laminate first, before separating into laminates destined for each battery (coin cells, stacked pouch, stacked prismatic, jelly roll pouch, jelly roll prismatic and jelly roll cylindrical).

[0190] After the separation into single-battery laminates, it is desired that both current collectors are engageable from the same end of the laminate. In fact, the separator and both current collectors may extend outside of the electrode area to the same degree, which prevents the simplified combing process illustrated in FIG. 6 because both the anode and a cathode spiral will be addressable.

[0191] Compared to FIG. 6, removal of part of the first and second current collectors is desired to allow access to one but not the other.

[0192] In FIG. 7, the battery laminate is a roll. Thus, a portion of the current collector 22 and portions of the current collector 12 have been removed at portions of the laminate being in the upper half of the roll. Clearly, contacting at either end would be possible if portions of the current collector 12 were instead removed in portions at the lower half.

[0193] Now, the current collectors may, as is seen in FIG. 6, be bent outwardly. The separators preferably extend outwardly between the outwardly extending portions of current collectors 12 and 22 so as to, as in relation to FIG. 6, ensure no short circuiting between one electrode and the current collector of the other electrode. In this manner, the upper (in the drawing) surface of the battery roll (end) may be used for contacting to one electrode and the other to the other electrode.

[0194] Clearly, multiple portions of the current collector 12 may extend outwardly at different circumferential portions, as may multiple portions of the current collector 22.

[0195] Also, the bending may be easier if the current collection portions to be bent do not extend a large portion of the circumference of a winding of the roll. Thus, the outwardly extending portions of e.g. current collector 12 may be divided into several narrower portions.

[0196] Preferably, a portion of the separator is removed, cut or severed between neighbouring portions of the extending portions of current collectors 12 and 22, so that the separator may be bent in the same manner as the current collectors.

[0197] Naturally, the portions of the current collectors may be removed prior to lamination. Alternatively, as will be described below, the removal may take place on the laminated structure.

[0198] Naturally the combing can also be inwards or even inwards for a part and outwards for another part of the jelly roll.

[0199] If the laminate is not rolled but folded, the same technology may be used so that the current collectors extend away from the laminate at one side of a folded laminate, but the current collector 12 is removed at one or more first portions along that side and the current collector is removed at other, second positions along the side. Then, the current collector at the first portions may be bent to one side, again with the separator preventing short circuiting, and the current collector at the second portions may be the same. Connection then will be very simple.

[0200] Is it noted that by the present methods, each winding or layer of the laminate may be connected—even at multiple positions if desired.

[0201] One way to connect could be to design a cap with holes in register with respectively the anode spiral and the cathode spiral in a first not electric conductive part of the cap an then apply solder or glue through the holes in the cap and perform the soldering or glue process. Alternatively, the cap can have multiple holes and the solder paste or glue paste can be applied with a vision control robotics process. The latter process entails the advantage of not requiring the design to be in register and to being able to utilize the powers of vision control processing to our advantage. In the two first mentioned principles the precise character of the separator is not important unless the temperature in par example the solder process exceeds the thermal limits for the separator and thus induce risk of shrinking or other physical deformation processes that compromise the separation between the electrodes and or the current collectors from the electrodes. Choosing the separators from among separators that are ceramic, are ceramic coated or are made from polymers with high heat resistance, as par example Aramid fibres, can mitigate this thermal compromising risk.

[0202] For the following laser shrinking principle, the combing process may be preceded by a vision controlled laser shrinking procedure where the laser track the areas of the laminate where the protruding anode and cathode current collectors should be shrunk to avoid the risk of them being exposed in the spirals/roll on particular areas. When the vision control system has receded respectively the anode current collector and the cathode current collector there will be a pattern of connectable anode current collectors and cathode current collectors as seen in FIG. 7.

[0203] This allows the same cap mount principles as explained in relation to FIG. 6. Laser optics move fast and vision control is highly accurate so the process is highly accurate, fast, repeatable and cost effective in high volume production environments.

[0204] Alternatively to handling the preparation for current collector to cap connection post roll to roll the process can also be performed in roll to roll domain by use of a system where heat resistant separators are used in conjunction with lasers focused to heat up and thus perform shrinking in a predetermined range of depths. The lasers can be placed in rows and be configured to shrink portions which are in register, such that the battery when readied for connection between current collector and cap obtains the correct positioning of the current collectors even for wound jelly rolls.

[0205] In order to protect the protruding current collector, which is not to be shrunk, the laser treatment can take place upon a cooled roller that limit the heating. Further, the wavelength of the laser can be tuned to be especially heating of one or more of the compound materials in the respective anode or cathode current collector, such that the light energy impinging upon the to-be-shrunk current collector will have a bigger effect upon it than upon the other current collector. The vision control system can further control the x,y laser focussing such that is mostly avoided to direct laser energy towards the current collector not to be shrunk as the upper current collector constantly shadows the current collector not to be shrunk.

[0206] Alternatives such as cutting with knife or handling the laser shrinking without the laminate have been formed are also conceivable. For example, each laminate layer would be required to be handled separately and then adjourned into the desired laminates.

[0207] The combing can be to either side and there are advantages for both sides. In the direction inwards to the centre of a jellyroll the spiral becomes smaller than the perimeter of the wound jelly roll, which is advantageous because there are no issues with the part of the combed materials jutting out and the cap can be produced in slightly smaller size and still connect all spirals. In the outward direction the combing action is naturally performed during the winding.

[0208] It should be mentioned that the combing will be facilitated when the current collectors are flexible, such as based on the laminate of FIG. 1.

[0209] One of the major advantages of the present connection manner is, beside the fact that the multiple connections to the roll will reduce resistive heat generation and associated losses, is that batteries connected in this way also achieves considerably better round trip efficiency through lower Ohmic resistance and far better charge and discharge rates as well as a much longer projected lifetime. Single or few tab connected standard batteries are plagued with local fast aging due to heat generation concentration due to heterogeneous electric field lines concentration that expend the part of the battery where there initially are the best electric conductivity. The tab-less mode uses the entire electrode laminate more evenly as a consequence the of more evenly distributed electric connectivity.

[0210] Another major advantage is that not only is less heat generated in response to Ohmic losses this heat generation is much lowered during high charge and discharge rates and moreover the heat is better ported out of the battery because the caps are feasible to connect thermally over a large area to the casing.

[0211] A last major advantage is the combing increase the space available for the jelly roll through increasing the length in both end relative to standard batteries where the void over and below the jelly roll is used for extensions of the separators and current collectors. This detail increases the Wh/kg and Wh/L and the Wh/$ by allowing proportionally more space and weight for the jelly roll.

[0212] When the battery is winded and connected to one or more caps it can be inserted into either a centrifugal dryer or a vacuum drying oven. The completion of the stack or jellyroll greatly reduce the volume of the laminates to be dried and thus the space consumption inside the vacuum oven and the energy consumption because the energy consumption scale with volume of the vacuum oven and the permeability of the laminate. Pre-drying with a centrifugal dryer greatly reduces the amount of solvent required to be removed and thus the time, volume and energy expenditure of the vacuum drying ovens. The centrifugal drying step can be further enhanced through forcing inert gas such as argon through the laminate. The centrifugal and gas forcing drying can be combined and reduce the drying time and temperature which limits the corrosion damaging of the electrode materials as the remaining vacuum oven drying can be performed faster and at lower. It should be noted that anodes frequently use demineralised water as solvent, which would lead to damaging corrosion of the cathode material. However, the anodes are generally less sensitive to heating so aggressive laser drying could dry out the anodes completely prior to the assembly of the laminate.

[0213] In FIG. 8a an electrode is shown before final calendaring and in 8b after the calendaring. Embossing electrolyte channels after calendaring defies the purpose because the embossing cause a steep local decrease in the porosity in and around the sidewalls of the electrolyte channels which naturally renders the embossed electrolyte channels completely useless waste of space and materials. However, provided the electrolyte channels are made oversize before the electrode is entering the final calendaring process the final electrolyte channels will be diffusion open for both slurry solvent drying and electrolyte infusion. As the electrode material implode into the oversize flow channels seen in FIG. 8a the gradient of porosity increases towards the centre of the flow channels. Relatively to par example laser ablation this collapsing electrode layer approach removes no materials and there is no risk of dust contamination or heat damage of the electrode materials. Further the process can be completed well in time before the drying out of the electrode material solvent begins.

[0214] Naturally, the laminate may alternatively be folded so as to fit into pouch type batteries or prismatic type batteries.