METHOD FOR MANUFACTURING BATTERIES, AND BATTERY OBTAINED BY THIS METHOD

Abstract

Battery comprising at least one anode and at least one cathode, arranged one above the other in an alternating manner, said battery comprising lateral edges comprising an anode connection zone and a cathode connection zone, preferably laterally opposite the anode connection zone, and longitudinal edges, wherein the anode comprises a current collector substrate, at least one anode layer, and optionally a layer of an electrolyte material, and the cathode comprises a current collector substrate, at least one cathode layer, and optionally a layer of an electrolyte material so that the battery successively comprises at least one anode layer, at least one layer of an electrolyte material and at least one cathode layer, characterized in that each anode and each cathode comprises a respective main body, separated from a respective secondary body by a space free of any electrode material,electrolyte and / or current collector substrate connecting opposite side edges of the battery.,

Description

Title of the invention: METHOD FOR MANUFACTURING BATTERIES, AND BATTERY OBTAINED BY THIS METHOD Technical field of the invention

[0001] The present invention relates to the manufacture of batteries. It can be applied in particular to lithium ion batteries. The invention relates to a new method for manufacturing batteries, and in particular lithium ion batteries. It also relates to the batteries obtained by this method, which have a new architecture which gives them an improved service life. State of the art

[0002] In order to increase the production efficiency of rechargeable batteries with high energy density and high power density, such as all-solid-state batteries or batteries impregnated with a liquid electrolyte, the simultaneous manufacture of several batteries can be carried out from a superposition of alternating anode and cathode sheets previously coated with a layer of electrolyte.

[0003] WO 2016 / 001584 (LTEN) describes sheets comprising a conductive substrate successively covered with an electrode layer covered with an electrolyte layer; these sheets are cut, before or after deposition, according to patterns, in particular in a U shape. These sheets are stacked alternately in order to constitute a stack of several elementary cells. The cutting patterns of the anodes and cathodes are placed in a "head to tail" configuration so that the stack of cathode and anode layers is laterally offset. After the stacking step, it is known from this document to deposit an encapsulation system in a thick layer of around ten microns and conformal, typically a polymeric layer, on the stack and in the available cavities present within the stack.This ensures, on the one hand, the rigidity of the structure at the cutting planes and, on the other hand, the protection of the battery cell from the atmosphere. Once the stack is made and encapsulated in a rigid structure, it is cut along cutting planes to obtain unit batteries, with the cathode and anode connections of the batteries being exposed on each of the cutting planes. It turns out that during these cuts, the encapsulation system can be torn off, which results in a discontinuity in the sealing of the battery. It is also known to add terminations (i.e. electrical contacts) at the level where these cathode and anode connections are visible.

[0004] This state of the art is explained here in greater detail with reference to [Fig. 12] which illustrates a lithium ion battery structure described in WO 2016 / 001584. The battery 200 comprises several anodes 230 and several cathodes 210, which are arranged one below the other in an alternating manner. Each anode and each cathode comprises a layer of a respective anode or cathode active material, called anode layer, respectively cathode layer. Furthermore, a layer of an electrolyte material, not shown in [Fig. 12], is interposed between the anode and the cathode, so that this electrolyte material separates two facing active layers. The thickness of the different layers which constitute them does not normally exceed 10 μm, and is often between 1 μm and 4 μm. The battery has, on a first lateral edge 201, anode connections 230' located one below the other. Furthermore, on the opposite longitudinal edge 202, cathode connections 210' are provided, located one below the other. The stack of anodes 230 and cathodes 210 is laterally offset.The cathode connections 210' are located protruding from the free face 230" of the anode. Similarly, on the opposite edge 202, the free face 210" of the cathode is located set back from the free face of the anode on which anode connections 230' are subsequently deposited.

[0005] This known solution, however, has certain drawbacks. Indeed, depending on the positioning of the electrodes, in particular the proximity of the edges of the electrodes for multi-layer batteries and the cleanliness of the cutouts, a leakage current may appear on the ends, typically in the form of a creeping short circuit. It reduces the performance of the battery, despite the use of an encapsulation system around the battery and around the cathode and anode connections. Furthermore, an unsatisfactory deposition of the encapsulation system on the battery is sometimes observed, in particular on the edges of the battery at the level of the spaces created by the lateral offsets of the electrodes on the edges of the battery.

[0006] Furthermore, given that the terminations, respectively anode and cathode, are located set back from the adjacent layers, respectively cathode and anode, it is necessary to make a large cut. Such a cut must then be filled with an insulating material. Given its large dimensions, this cut leads to a substantial loss of useful materials, for the production of the battery itself. Furthermore, it requires depositing large thicknesses of insulation, in the available cavities present within the stack. A thick insulator risks weakening the entire encapsulation system of the battery, because during cutting, the encapsulation system deposited in a thick layer tends to delaminate. The architecture according to the state of the art therefore has both technical and economic disadvantages.

[0007] The present invention aims to remedy at least in part certain drawbacks of the prior art mentioned above.

[0008] It aims in particular to increase the production yield of rechargeable batteries with high energy density and high power density and to produce more efficient encapsulations at lower cost.

[0009] It aims in particular to propose a process which reduces the risk of short circuit, and which makes it possible to manufacture a battery with low self-discharge.

[0010] It aims in particular to propose a method which makes it possible to manufacture in a simple, reliable and rapid manner a battery having a very long service life.

[0011] It also aims to propose such a method, which uses a cutting step of better quality than in the prior art.

[0012] It also aims to propose such a method, which makes it possible to improve the encapsulation phases and the encapsulation itself, occurring during the production of the final battery.

[0013] It also aims to propose a battery manufacturing process which results in less loss of materials. Objects of the invention

[0014] At least one of the above objectives is achieved by means of at least one of the objects according to the invention as presented below. The present invention proposes as a first object a battery comprising at least one anode and at least one cathode, arranged one above the other in an alternating manner, said battery comprising lateral edges comprising an anode connection zone and a cathode connection zone, preferably laterally opposite the anode connection zone, and longitudinal edges, wherein the anode comprises - a current collector substrate, - at least one anode layer, and - possibly a layer of an electrolyte material or a separator impregnated with an electrolyte,

[0015] and the cathode comprises - a current collector substrate, - at least one cathode layer, and - possibly a layer of an electrolyte material or a separator impregnated with an electrolyte,

[0016] so that the battery successively comprises at least one anode layer, at least one layer of an electrolyte material or of a separator impregnated with an electrolyte and at least one cathode layer,

[0017] characterized in that each anode and each cathode comprises a respective main body, and a respective secondary body, said main bodies and secondary bodies being separated by a space free of any electrode material, electrolyte and / or current collector substrate connecting opposite side edges of the battery.

[0018] The present invention proposes as a second object a battery comprising at least one anode and at least one cathode, arranged one above the other in an alternating manner, said battery comprising lateral edges comprising an anode connection zone and a cathode connection zone, preferably laterally opposite the anode connection zone, and longitudinal edges, in which the anode comprises - a current collector substrate, - at least one anode layer, and - possibly a layer of an electrolyte material or a separator impregnated with an electrolyte,

[0019] and the cathode comprises - a current collector substrate, - at least one cathode layer, and - optionally a layer of an electrolyte material or a separator impregnated with an electrolyte,

[0020] such that the battery successively comprises at least one anode layer, at least one layer of an electrolyte material or of a separator impregnated with an electrolyte, and at least one cathode layer,

[0021] characterized in that each anode and each cathode comprises a respective main body, separated from a respective secondary body by a space free of any electrode material, electrolyte and / or current collector substrate connecting the opposite lateral edges of the battery.

[0022] Advantageously, the battery comprises an encapsulation system completely covering four of the six faces of said battery, the two remaining faces comprising an anode connection zone and a cathode connection zone.

[0023] Advantageously, the encapsulation system comprises: - at least one first covering layer, preferably chosen from parylene, parylene type F, polyimide, epoxy resins, silicone, polyamide, sol-gel silica, organic silica and / or a mixture thereof, deposited on the battery, - at least one second covering layer composed of an electrically insulating material, deposited by atomic layer deposition on said at least one first covering layer,

[0024] it being understood that this sequence of at least one first covering layer and at least one second covering layer can be repeated z times with z > 1.

[0025] Advantageously, the anode connection zone and the ca- connection zone Theodic are covered by a termination system.

[0026] Advantageously, the termination system successively comprises: - a first layer of a graphite-loaded material, preferably based on graphite-loaded epoxy resin, - a second dense layer of metallic copper arranged on the first layer of the termination system, and - optionally, a third layer based on a tin-zinc alloy of tin, placed on the second layer, - optionally, a fourth layer based on tin or based on an alloy of silver, palladium and copper, placed on the third layer of the termination system.

[0027] Advantageously, the width of the free space is between 0.01 mm and 0.5 mm. Advantageously, the width of the secondary bodies is between 0.05 mm and 2 mm.

[0028] Another object of the invention is a method of manufacturing a battery, said battery comprising at least one anode and at least one cathode, arranged one above the other in an alternating manner, said battery comprising longitudinal edges and lateral edges,

[0029] wherein the anode comprises - a current collector substrate, - at least one anode layer, and - possibly a layer of an electrolyte material or a separator impregnated with an electrolyte,

[0030] and the cathode comprises - a current collector substrate, - at least one cathode layer, and - possibly a layer of electrolyte material or a separator impregnated with an electrolyte

[0031] so that the battery successively comprises at least one anode layer, at least one layer of an electrolyte material or of a separator impregnated with an electrolyte, and at least one cathode layer,

[0032] each anode comprising an anode connection zone, located in the vicinity of a first lateral edge of the battery, while each cathode comprises a cathode connection zone, located on a second lateral edge of the battery, opposite said first edge,

[0033] said manufacturing method comprising: has. the supply of a stack of alternating sheets, this stack comprising first sheets or anode sheets each of which is

[0034]

[0035]

[0036]

[0037]

[0038] intended to form an anode layer of several batteries, as well as second sheets or cathode sheets each of which is intended to form a cathode layer of several batteries, each anode sheet comprising at least one anode slot and each cathode sheet comprising at least one cathode slot, said anode and cathode slot respectively comprising two longitudinal parts at least partly superimposed, intended to delimit the lateral edges of the battery, as well as a lateral part connecting said two longitudinal parts, the lateral part of the anode slot and the lateral part of the cathode slot extend mutually offset, a. carrying out a heat treatment and / or a mechanical compression of the stack of alternating sheets previously supplied, b. making two cutouts extending at least partially inside said slots, the first cutout extending between the lateral portion of the anode slot and the facing end of the longitudinal portions, while the second cutout extends between the lateral portion of the cathode slot and the facing end of the longitudinal portions. Advantageously, after step c), the encapsulation of the cut stack is carried out by depositing: - at least one first covering layer, preferably chosen from parylene, parylene type F, polyimide, epoxy resins, silicone, polyamide, sol-gel silica, organic silica and / or a mixture thereof, on the battery, and then - at least one second covering layer composed of an electrically insulating material, deposited by atomic layer deposition on said at least one first covering layer, provided that the sequence of at least one first covering layer and at least one second covering layer may be repeated z times with z > 1. Advantageously, after step d) of encapsulating the cut stack, the cut and encapsulated stack is impregnated with a lithium ion-carrying phase such as liquid electrolytes or an ionic liquid containing lithium salts. Advantageously, the battery terminations are made by successively depositing: - a first layer of a graphite-loaded material, preferably based on graphite-loaded epoxy resin, - a second dense layer of metallic copper arranged on the first layer of the termination system, and - optionally, a third layer based on a tin-zinc alloy of tin, arranged on the second layer of the termination system, - optionally, a fourth layer based on tin or based on an alloy of silver, palladium and copper, arranged on the third layer of the termination system.

[0039] Advantageously, the two cuts are made through at least a majority of the anodes and cathodes, in particular through all of the anodes and cathodes.

[0040] Advantageously, the distances between each cutout and the opposite ends of the longitudinal parts are identical. Advantageously, its distances are between 0.05 mm and 2 mm.

[0041] Advantageously, each slot has an overall H shape, the longitudinal parts forming the main vertical recesses of the H, while the lateral part forms the channel of the H.

[0042] Advantageously, each lateral part of the slots delimits a space free of any electrode material, electrolyte and / or current collector substrate connecting the opposite lateral edges of the battery, said free space separating, for each anode and each cathode, a main body from a secondary body.

[0043] Advantageously, the width of the lateral part is between 0.05 mm and 2 mm.

[0044] Advantageously, each sheet belonging to said stack comprises several slit lines arranged next to each other, and in that the two cuts are made through all the slits of the same line.

[0045] Advantageously, each sheet comprises several rows of slots arranged one below the other.

[0046] Advantageously, the distance separating adjacent cutouts, made in neighboring lines, is between 0.05 mm and 5 mm.

[0047] Advantageously, the number of lines is between 10 and 500, while the number of rows is between 10 and 500.

[0048] Advantageously, each cut is made by a sawing process, by a dicing process, by guillotine, or by laser. Figures

[0049] The attached figures, given as non-limiting examples, represent different aspects and embodiments of the invention. [Fig. 12] represents a battery according to the state of the art.

[0050] [Fig.l] is a perspective view of the anode and cathode sheets intended to form a stack according to the battery manufacturing method according to the invention.

[0051] [Fig.2] is a front view, illustrating one of the leaves of [Fig.l].

[0052] [Fig.3] is a front view, on a larger scale, illustrating H-shaped slots arranged in adjacent leaves.

[0053] [Fig.4] is a perspective view, also on a large scale, illustrating these slits in H-shaped structures formed in adjacent leaves.

[0054] [Fig.5] is a top view, illustrating a cutting step carried out on different slots made in the stacking of the previous figures.

[0055] [Fig.6] is a top view, illustrating on a larger scale the cutouts made on an H-shaped slot.

[0056] [Fig.7] and [Fig.8] are sectional views, along the respective lines VII-VII and VIII- VIII indicated in [Fig.6].

[0057] [Fig.9], [Fig. 10] and [Fig.1 1] are views respectively from above, from the front, and from perspective, illustrating a battery in accordance with the invention, which can be obtained in particular according to the method of the preceding figures.

[0058] [Fig. 12] is a perspective view illustrating a battery according to the prior art.

[0059] [Fig. 13] is a top view, illustrating a cutting step carried out on different H-shaped slots provided on an anode or cathode sheet according to a second variant of the invention.

[0060] [Fig. 14] is a top view, illustrating on a larger scale the cutouts made on H-shaped slots according to the second variant of the invention.

[0061] [Fig. 15] is a perspective view, illustrating a battery according to the invention, which can be obtained in particular according to the second variant of the invention.

[0062] The following references are used in these figures and in the description which follows:

[0063] [Table 1]: benchmarks used in the present application I stack of anode and cathode sheets 1 cathode sheet XH / XH' horizontal median axis of slots 14 and 34, respectively of slots 1014 and 1034 3 anode sheet D, D', Dn, D n, Dn+1, D'n+1 Cutout 10 perforated central zone of the cathode sheet 100 / 1100 Battery according to the invention 12 peripheral frame of the cathode sheet 40 / 1040 material scraps XX longitudinal or horizontal direction of the stack 41 cathode material scraps YY vertical or transverse direction of the stack 43 anode material scraps L line of slots X 100 Y 100 longitudinal and transverse centerlines of 100 R row of slots 101 / 102 lateral edges of 100 20 / 1020 bridges of material between two lines 103 / 104 longitudinal edges of 100 H20 / H1020 heights of the bridges 110 / 1110 cathode layers 22 strips of material between two rows 130 / 1130 anode layers L22 width of the strips 111, 131 / 1111, 1131 main body of 110, respectively of 130 / main body of 1110, respectively of 1130 14 / 1014 H-shaped slots in the cathode sheets 112, 132 / 1112, 1132 secondary body of 110, respectively of 130 / secondary body of 1110, respectively of 1130 16 / 1016 vertical main recesses of 14 113 / 1113 free space between 111 and 112, respectively between 1111 and 1112, of any electrode material,of electrolyte and / or current collector substrate 18 / 1018 horizontal channel of 14 133 / 1133 free space between 131 and 132, respectively between 1131 and 1132, of any electrode, electrolyte and / or current collector substrate material H14 total height of the slot L113 / L1113 width of the free space between 111 and 112, respectively between 1111 and 1112 L14 total width of the slot L112 / Li 112 width of the secondary body 112, respectively 1112 L16 width of each nr, 112', free faces respectively of 111, , main recess 16 131', 132' 112, 131, 132 H18 height of each channel 18 200 prior art batteries see figure 12 Dis distance between the top of 16 and 18 210 / 230 cathode / anode 34 / 1034 H-shaped slots in the anode sheets, analogous to the slots 14 / 1014 201 / 202 side edges 36 / 1036 vertical main recesses of 34 210' / 230' free faces of the cathode / anode. 1101 / 1102 side edges of 1100 210” / 230” free faces of the cathode / anode located indented 38 / 1038 horizontal channel of 34 D20 distance between the cutout Dn and the opposite face of the channel 18 2 Perforations present at the four ends of the anode and cathode sheets D40 distance between the cutout D'n and the opposite face of the channel 38 D1020 distance between the cutout Dn and the opposite face of the channel 1018 D38 distance between the top of 36 and 38 Description of the invention

[0064] The method according to the invention firstly comprises a step in which a stack I of alternating sheets is produced, these sheets being referred to below, as appropriate, as "anode sheets" and "cathode sheets". As will be seen in more detail, each anode sheet is intended to form the anode of several batteries, and each cathode sheet is intended to form the cathode of several batteries. In the example illustrated in [Fig.l], five cathode sheets 1 and five anode sheets 3 are shown. In practice, this stack is formed by a higher number of sheets, typically between ten and a thousand. In an advantageous embodiment, all these sheets have perforations 2 at their four ends so that when these perforations 2 are superimposed, all the cathodes and all the anodes of these sheets are arranged specifically, as will be explained in greater detail below (see figures 1 and 2). These perforations 2 at the four ends of the sheets can be made by any suitable means, in particular on anode and cathode sheets after manufacture or on anode and / or cathode sheets coated with a layer of electrolyte or coated with a separator so that this layer of electrolyte or this separator is interposed between two sheets of opposite polarity, i.e. between the anode sheet and the cathode sheet.

[0065] The physicochemical structure of each anode or cathode sheet, which may be of a known type, is not part of the invention and will only be described briefly. Each anode sheet, respectively cathode sheet, comprises an active anode layer, respectively an active cathode layer. Each of these active layers may be solid, i.e. dense or porous in nature. Furthermore, in order to avoid any electrical contact between two adjacent sheets, an electrolyte layer or a separator impregnated with a liquid electrolyte is arranged on at least one of these two sheets, in contact with the facing sheet. The electrolyte layer or the separator impregnated with a liquid electrolyte, not shown in the figures describing the present invention, is interposed between two sheets of opposite polarity, i.e. between the anode sheet and the cathode sheet.

[0066] The mechanical structure of one of the cathode sheets 1 will now be described, it being understood that the other cathode sheets have an identical structure. Furthermore, as will be seen in the following, the anode sheets 3 have a structure very similar to that of the cathode sheets 1.

[0067] As can be seen in [Fig.2], the cathode sheet 1 has a quadrilateral shape, substantially of the square type. It delimits a central zone 10 called perforated, in which H-shaped slots are arranged which will be described below. With reference to the positioning of these H-shaped slots, a so-called vertical direction YY of the sheet is defined, which corresponds to the vertical direction of these Hs, as well as a so-called horizontal direction XX of the sheet, perpendicular to the YY direction. The central zone 10 is bordered by a peripheral frame 12 which is solid, namely without slots. The function of this frame is in particular to ensure easy handling of each sheet.

[0068] The H-shaped slots are distributed along lines Lx to Ly, arranged one below the other, as well as along rows Ri to Rx provided next to each other. As non-limiting examples, in the context of the manufacture of surface-mountable component (hereinafter CMS) type microbatteries, the anode and cathode sheets used may be 100 mm x 100 mm plates. Typically, the number of lines of these sheets is between 10 and 500, while the number of rows is between 10 and 500. Depending on the desired capacity of the battery, its dimensions can vary and the number of lines and rows per anode and cathode sheets can be adapted accordingly. The dimensions of the anode and cathode sheets used can be modulated according to requirements. As shown in [Fig.2], two adjacent lines are separated by bridges of material 20, whose height is noted H20, which is between 0.05 mm and 5 mm. Two adjacent rows are separated by strips of material, whose width is noted L 22, which is between 0.05 mm and 5 mm. These bridges and strips of material of the anode and cathode sheets give them sufficient mechanical rigidity so that they can be handled easily.

[0069] The slots 14 are through-slots, namely they open onto the upper and lower faces respectively of the sheet. The slots 14 can be made in a manner known per se, directly on the substrate, before any deposition of anode or cathode materials by chemical etching, electroforming, laser cutting, microperforation or stamping. These slots can also be made on substrates coated with anode or cathode materials, on anode or cathode sheets coated with a layer of electrolyte or a separator, in a manner known per se, for example by laser cutting, femtosecond laser cutting, microperforation or stamping. The slots 14, made in all the anodes, are superimposed as shown in particular in [Fig. 3].

[0070] One of the H-shaped slots 14 will now be described, it being understood that all of the cutouts in the anode sheet are identical. The slot 14 is formed by two main vertical and parallel recesses 16, which are connected in their upper part by a horizontal channel 18, preferably perpendicular to the two main vertical recesses 16. Note H14 the height of the entire slot, which is typically between 0.25 mm and 10 mm; • Li4 its width, which is typically between 0.25 mm and 10 mm; • Li6 the width of each main recess, which is typically included between 0.02 mm and 5 mm; • Hi8 the height of each channel, which is typically between 0.01 mm and 0.5 mm; • Di8 the difference in height between the top of the main recesses and the top of the channel, which is typically between 0.05 mm and 2 mm.

[0071] Each cathode is also provided with different lines and rows of slots 34, provided in the same number as the slots 14. As shown in particular in [Fig. 4], the structure of each slot 34 is substantially similar to that of each slot 14, namely that this slot 34 comprises two main vertical recesses 36, connected by a channel 38. The dimensions of the main vertical recesses 36 are identical to those of the main vertical recesses 16 and, similarly, the dimensions of the channels 38 are similar to those of the channels 18.

[0072] In top view, the main vertical recesses 36 are superimposed with those 16. The only difference between the slots 14 and 34 lies in the fact that the channels 38 are provided in the lower part. As shown in particular in [Fig. 3], the channels 18 and 38 are mutually symmetrical in top view, relative to the median axis of the H, which is noted XH.

[0073] It is assumed that the stack, described above, is subjected to steps aimed at ensuring its overall mechanical stability. These steps, of a type known per se, include in particular the heat pressing of the different layers. As will be seen below, this stack allows the formation of individual batteries, the number of which is equal to the product between the number of lines Y and the number of rows X.

[0074] For this purpose, with reference to [Fig. 5], three lines Ln.i to Ln+i have been illustrated, as well as three rows Rn.i to Rn+i. In accordance with the invention, two cuts Dn and D'n are made per line of slots. Each cut, which is made in a through manner, namely that it extends over the entire height of the stack, is made in a manner known per se. As non-limiting examples, mention may be made of cutting by sawing, in particular dicing, guillotine cutting or laser cutting.

[0075] As shown in particular in [Fig.6], which is a larger scale view of one of the slots of [Fig.5], each cut is made between a respective channel and the opposite end of the H. It is assumed that the thickness of said cut is neglected. Under these conditions, with reference to this [Fig.6], as non-limiting examples, we note: • the distance D20 between the cutout Dn and the opposite face of the horizontal channel 18 is between 0.05 mm and 2 mm, it being understood that this distance D20 is less than or equal to Di8; • the distance D4o between the cutout D'n and the opposite face of the horizontal channel 38, between 0.05 mm and 2 mm, it being understood that this distance D4o is less than or equal to D38.

[0076] Referring again to [Fig.5], each final battery is delimited, at the top and bottom, by the two cutouts and, on the right and left, by the inner faces of the main vertical recesses of the H. In this [Fig.5] the batteries 100 have been hatched once cut out by the cutting lines Dn and D'n, the zones 40 of the sheets of the stack, which do not form the batteries, have been illustrated with dots, while the volume of the slots is left blank.

[0077] Figures 7 and 8 are sectional views, taken along parallel section lines. Section VII-VII extends through the main vertical recesses of the H, while that the VIII-VIII cut crosses the material. In [Fig. 7], the zones 40, also illustrated in [Fig. 5], have been referenced, which correspond to material scraps, in particular scraps of anode materials 43 and cathode materials 41. In [Fig. 8] it is noted that the cuts are made both through the anodes and the cathodes, namely at a distance D20 from the channels of the H-shaped slots so as to have for each cathode 1, respectively each anode 3 of the battery 100 a main body 111, respectively 131, separated from a secondary body 112, respectively 132, by a space free of any electrode material, electrolyte and / or current collector substrate 113, respectively 133. This is a particularly advantageous characteristic of the invention, since it makes it possible to improve the quality of the cut with regard to the prior art and to avoid the presence of short circuit at the side edges of the battery.

[0078] Application WO 2016 / 001584 describes stacks of several elementary cells, consisting of anode and cathode sheets stacked alternately and laterally offset (see [Fig. 12]), encapsulated in an encapsulation system to ensure protection of the battery cell from the atmosphere. The cutting of these encapsulated stacks making it possible to obtain unit batteries, with exposed anode and cathode connections, is carried out along a cutting plane passing through an alternating succession of electrodes and encapsulation systems. Due to the difference in density existing between the electrode and the encapsulation system of the battery of the prior art, the cutting carried out along this cutting plane induces a risk of tearing off the encapsulation system near the cutting plane, and thus the creation of short circuits.In the prior art, during encapsulation, the encapsulation layer fills the interstices of the stack of sheets bearing U-shaped cutouts. This encapsulation layer introduced at the level of these interstices is thick and does not adhere very well to the stack, leading to this risk of tearing off the encapsulation system during subsequent cutting.

[0079] According to the present invention, this risk is eliminated with the use of sheets bearing H-shaped cutouts, because the H-shaped heat-pressed mechanical structure is extremely rigid around the cutout, due to the alternating superposition of cathode and anode sheets. The use of such a rigid structure, with the use of sheets bearing H-shaped cutouts, makes it possible to reduce the number of defects during cutting, to increase the cutting speed and thus to improve the production yield of the batteries.

[0080] According to the invention, the cuts D'n and Dn are carried out through the anodes and cathodes of comparable density, resulting in a clean cut of better quality. In addition, the presence of a space free of any electrode material, electrolyte and / or current collector substrate prevents any risk of short circuit.

[0081] Referring now to Figures 9 to 11, one 100 of the batteries according to the invention has been illustrated. X100 and Y100 denote the median longitudinal and transverse axes respectively of this battery. 101 and 102 denote the lateral edges, 103 and 104 the longitudinal edges of this battery. Furthermore, 110 denotes each cathode, and 130 each anode. The number of these cathodes, which is identical to the number of these anodes, corresponds to the number of cathode sheets and anode sheets of the stack above.

[0082] Each cathode 110 comprises a main body 111, a secondary body 112 located on a first lateral edge 101, as well as a space free of any electrode material, electrolyte and / or current collector substrate 113. The latter, whose width corresponds to that of the channel 18 of the slot 14 described above, extends between the longitudinal edges 103 and 104. Similarly, each anode 130 comprises a main body 131, as well as a secondary body 132 located on the lateral edge 102, opposite that 101. The main body 131 and the secondary body 132 are separated by a space 133 free of any electrode material, electrolyte and / or current collector substrate, connecting the edges 103 and 104. The 2 free spaces 113 and 133 are mutually symmetrical, with respect to the median axis Y100.

[0083] The width Ln3 of each free space 113 corresponds to the width of the channel 18, belonging to the slot described in the preceding figures. Furthermore, the width Ln2 of each secondary body 112 corresponds to the distance D2o, as described with reference to [Fig.6] or [Fig.8].

[0084] [Fig. 13] illustrates a further variant of the invention. In this [Fig. 13] the mechanical elements similar to those of figures 1 to 11 illustrating the first embodiment are assigned the same reference numbers increased by the number 1000.

[0085] This second variant embodiment differs from the first variant essentially in that the H-shaped slots 1014 are distributed along lines Lx to Ly, arranged one below the other, as well as along rows Ri to Rx provided next to each other. In this way, at least one of the main vertical recesses 1016 of the slot positioned in row Rn is merged with at least one of the main vertical recesses 1016 of the adjacent slot positioned in row Rn and / or Rn+i. In this case, the two adjacent rows are not separated by strips of material. As shown in [Fig.13], two adjacent lines are separated by bridges of material 1020, the height of which is noted H1020, which is between 0.05 mm and 5 mm. These bridges of material give the anode and cathode sheets sufficient mechanical rigidity so that they can be handled easily.

[0086] In this second variant of the invention, the H-shaped slots 1014 can preferably be the same as in the first variant. The slot 1014 is preferably formed by two main vertical and parallel recesses 1016, which are connected in their upper part by a horizontal channel 1018, preferably perpendicular to the two main vertical recesses 1016.

[0087] Each cathode is provided with different lines and rows of slots 1014. Each anode is also provided with different lines and rows of slots 1034, provided in the same number as the slots 1014.

[0088] The structure of each slot 1034 is substantially similar to that of each slot 1014, namely that this slot 1034 comprises two vertical main recesses 1036, connected by a channel 1038. The dimensions of the vertical main recesses 1036 are identical to those of the vertical main recesses 1016 and, similarly, the dimensions of the channels 1038 are similar to those of the channels 1018.

[0089] In top view, the main vertical recesses 1036 are superimposed with the main vertical recesses 1016. The only difference between the slots 1014 and 1034 lies in the fact that the channels 1038 are provided in the lower part. As shown in particular in [Fig. 14], the channels 1018 and 1038 are mutually symmetrical in top view, relative to the median axis of the H, which is noted XH'.

[0090] It is assumed that the stack of anode and cathode sheets, described above, is subjected to steps aimed at ensuring its overall mechanical stability. These steps, of a type known per se, include in particular the heat pressing of the different layers. As will be seen below, this stack allows the formation of individual batteries, the number of which is equal to the product between the number of lines Y and the number of rows X.

[0091] For this purpose, with reference to [Fig. 14], three lines Ln.i to Ln+i are illustrated, as well as three rows Rn.i to Rn+i. In accordance with the invention, two cuts Dn and D'n are made per line of slots. Each cut, which is made in a through manner, i.e. it extends over the entire height of the stack, is made in a manner known per se. Non-limiting examples include sawing, in particular dicing, guillotine cutting or laser cutting.

[0092] Each cutout is made between a respective channel and the opposite end of the H. It is assumed that the thickness of said cutout is neglected. The cutouts are made both through the anodes and the cathodes, namely at a distance Dio2o from the channels of the H-shaped slots so as to have for each cathode 1110, respectively each anode 1130 of the battery 1100, a main body 1111, respectively 1131, separated from a secondary body 1112, respectively 1132, by a space free of any electrode material, electrolyte and / or current collector substrate 1113, respectively 1133, as illustrated in [Fig.15]. This is a characteristic particularly advantageous of the invention, since this makes it possible to improve the quality of the cutting with regard to the prior art and to avoid the presence of short circuits at the lateral edges of the battery. Each final battery 1100 is delimited, at the top and bottom, by the two cutouts and, on the right and left, by the inner faces of the main vertical recesses of the H. In [Fig. 13] the batteries 1100 have been hatched once cut by the cutting lines Dn and D'n, the areas 1040 of the sheets of the stack, which do not form the batteries, have been illustrated with points, while the volume of the slots is left blank.

[0093] According to the invention, the cuts D'n and Dn are carried out through the anodes and cathodes of comparable density, resulting in a clean, high-quality cut. In addition, the presence of a space free of any electrode material, electrolyte and / or current collector substrate prevents any risk of short circuit.

[0094] As shown in [Fig.15], each cathode 1110 comprises a main body 1111, a secondary body 1112 located on a first lateral edge 1101, as well as a space 1113 free of any electrode material, electrolyte and / or current collector substrate. The latter, whose width corresponds to that of the channel 1018 of the slot 1014 described above, extends between the longitudinal edges. Similarly, each anode 1130 comprises a main body 1131, as well as a secondary body 1132 located on the lateral edge 1102, opposite that 1101. The main body 1131 and the secondary body 1132 are separated by a space 1133 free of any electrode material, electrolyte and / or current collector substrate, connecting the longitudinal edges. The two free spaces 1113 and 1133 are mutually symmetrical, with respect to the median axis Y100.

[0095] The width Lm3 of each free space 1113 corresponds to the width of the channel 1018, belonging to the slot described in the preceding figures. Furthermore, the width Lm2 of each secondary body 1112 corresponds to the distance Dio2o, as described previously.

[0096] The battery 1100 obtained according to the second variant of the invention is in all respects identical to that obtained according to the first variant of the invention even though the arrangement of the slots 1014 is different.

[0097] In a third variant of the invention which is not shown in the figures, the H-shaped slots 14 / 1014 may be distributed along lines Lx to Ly, arranged one below the other, as well as along rows Ri to Rx provided next to each other. In this way, on the same anode and / or cathode sheet, the H-shaped slots 14 / 1014 are arranged according to the first and second variants of the invention, on the anode and / or cathode sheets, so as to maintain sufficient mechanical rigidity so that these sheets can be handled easily and so that the stack can advantageously define a maximum number of unit batteries.

[0098] The battery 1100 obtained according to the third variant of the invention is in every respect identical to that obtained according to the first and / or second variants according to the invention even though the arrangement of the slots 14 / 1014 on the anode and / or cathode sheets is different.

[0099] The comparison between Figures 11 and 12 makes it possible to highlight the advantages of the invention. Indeed, substantially the entire overall volume of the battery is occupied by useful material, i.e. which contributes to the electrochemical operation of the battery 100. Indeed, only the two free spaces 133 / 1133, of very small size, cannot be considered as useful material. In this respect, with reference to [Fig. 10], it is noted that the free faces 112' of the secondary cathode bodies are flush with the free faces 131' of the main body of the anodes, whereas the free faces 132' of the secondary anode bodies are flush with the free faces 111' of the main body of the cathodes. In other words, the opposite lateral edges of the battery according to the invention, comprising electrode materials, are substantially continuous, compared with those of the prior art illustrated in [Fig. 12], which are discontinuous due to the presence of withdrawals.

[0100] Furthermore, the presence of free spaces on each anode layer, respectively cathode layer of the battery makes it possible to dispense with the use of any encapsulation system, i.e. any insulating material, such as parylene within the battery, these free spaces playing the role of electrical insulation. The final stages of battery manufacturing, such as encapsulation, are facilitated. It is no longer necessary, as in the prior art and illustrated in [Fig.12], to isolate the recessed regions 210”, 230” within the battery, i.e. to fill the interstices of the structure of the prior art with an encapsulation system, to fill the space present in the U-shaped cutouts positioned head to tail and offset by an encapsulation system to avoid any short circuit.The use of a rigid structure according to the invention, with the use of sheets bearing H-shaped cutouts, makes it possible to facilitate encapsulation and to reduce the encapsulation thicknesses with respect to the prior art. Multi-layer encapsulation systems with thinner and more rigid layers than those of the prior art can be envisaged.

[0101] Advantageously, after the step of stacking the anode and cathode sheets, the heat treatment of the latter allowing the assembly of the battery is carried out at a temperature of between 50°C and 500°C, preferably at a temperature of less than 350°C, and / or the mechanical compression of the stack of anode and cathode sheets to be assembled is carried out at a pressure of between 10 and 100 MPa, preferably between 20 and 50 MPa. In a particular embodiment, it is advantageous, after the step of stacking and heat treatment of the latter, to encapsulate the stack by depositing an encapsulation system to ensure the protection of the battery cell from the atmosphere. The encapsulation system must be chemically stable, withstand high temperatures and be impermeable to the atmosphere to perform its barrier layer function. Advantageously, the stack of anode sheets and cathode sheets according to the invention may be covered with a sequence, preferably z sequences, of an encapsulation system comprising: - a first covering layer, preferably chosen from parylene, parylene type F, polyimide, epoxy resins, silicone, polyamide and / or a mixture thereof, deposited on the stack of anode and cathode sheets, - a second covering layer composed of an electrically insulating material, deposited by atomic layer deposition on said first covering layer.

[0102] This sequence can be repeated z times with z > 1. This multilayer sequence has a barrier effect. The more the sequence of the encapsulation system is repeated, the greater this barrier effect will be. It will be all the more important as the number of thin layers deposited is large.

[0103] Typically, the first covering layer is made of polymer, for example silicone (deposited for example by impregnation or by plasma-assisted chemical vapor deposition from hexamethyldisiloxane (HMDSO)), or epoxy resin, or polyimide, polyamide, or poly-para-xylylene (better known as parylene). This first covering layer makes it possible to protect the sensitive elements of the battery from its environment. The thickness of said first covering layer is preferably between 0.5 μm and 3 μm.

[0104] Advantageously, the first covering layer may be made of parylene type C, parylene type D, parylene type N (CAS 1633-22-3), parylene type F or a mixture of parylene type C, D, N and / or F. Parylene (also called poly-paraxylylene or poly(p-xylylene)) is a dielectric, transparent, semi-crystalline material which has high thermodynamic stability, excellent resistance to solvents and very low permeability. Parylene also has barrier properties making it possible to protect the battery from its external environment. The protection of the battery is increased when this first covering layer is made from parylene type F.This first covering layer is advantageously obtained from the condensation of gaseous monomers deposited by chemical vapor deposition (CVD) on the surfaces, which makes it possible to have a conformal, thin and uniform covering of all the accessible surfaces of the stack. This first covering layer is advantageously rigid; it cannot be considered a soft surface.

[0105] The second covering layer is composed of an electrically insulating material, preferably inorganic. It is deposited by atomic layer deposition (ALD), so as to obtain a conformal covering of all the accessible surfaces of the stack previously covered with the first covering layer. The layers deposited by ALD are very mechanically fragile and require a rigid support surface to ensure their protective role. The deposition of a fragile layer on a flexible surface would lead to the formation of cracks, causing a loss of integrity of this protective layer. Furthermore, the growth of the layer deposited by ALD is influenced by the nature of the substrate. A layer deposited by ALD on a substrate having zones of different chemical natures will have inhomogeneous growth, which may cause a loss of integrity of this protective layer.

[0106] ALD deposition techniques are particularly well suited to covering surfaces with high roughness in a completely sealed and conformal manner. They allow the production of conformal layers, free from defects, such as holes (so-called "pinhole free" layers, i.e. free from holes) and represent very good barriers. Their WVTR coefficient is extremely low. The WVTR coefficient (water vapor transmission rate) makes it possible to evaluate the water vapor permeance of the encapsulation system. The lower the WVTR coefficient, the more waterproof the encapsulation system is.

[0107] The second covering layer may be made of ceramic material, glassy material or glass-ceramic material, for example in the form of oxide, of the Al2O3 type, nitride, phosphates, oxynitride, or siloxane. This second covering layer preferably has a thickness of between 10 nm and 50 nm.

[0108] This second covering layer deposited by ALD on the first covering layer makes it possible, on the one hand, to ensure the sealing of the structure, i.e. to prevent the migration of water inside the object and, on the other hand, to protect the first covering layer, preferably of type F parylene, from the atmosphere, in particular from air and humidity, from thermal exposure in order to avoid its degradation. This second covering layer improves the lifetime of the encapsulated battery.

[0109] The stack of anode and cathode sheets thus encapsulated in this sequence of the encapsulation system, preferably in z sequences, can then be coated with a final covering layer so as to mechanically protect the stack thus encapsulated and possibly give it an aesthetic appearance. This final covering layer protects and improves the lifetime of the battery. Advantageously, this final covering layer is also chosen for withstand high temperature, and has sufficient mechanical strength to protect the battery during its subsequent use. Advantageously, the thickness of this last covering layer is between 1 μm and 50 μm. Ideally, the thickness of this last covering layer is around 10-15 μm, such a thickness range helps protect the battery from mechanical damage.

[0110] This last covering layer is preferably based on epoxy resin, polyethylene naphthalate (PEN), polyimide, polyamide, polyurethane, silicone, sol-gel silica or organic silica. Advantageously, this last covering layer is deposited by dipping.

[0111] The stack of anode and cathode sheets thus coated is then cut by any suitable means along the cutting lines D'n and Dn so as to expose the anode and cathode connections and to obtain unit batteries.

[0112] In the case of batteries impregnated with a liquid electrolyte, the impregnation of the battery with a liquid electrolyte is advantageously carried out, after obtaining the unit batteries whose anode and cathode connections are exposed, by a phase carrying lithium ions such as liquid electrolytes or an ionic liquid containing lithium salts; this phase carrying lithium ions penetrates into the battery by capillarity.

[0113] Terminations (electrical contacts) are added at the level where the cathodic, respectively anodic connections are visible (not coated with insulating electrolyte). These contact areas are preferably arranged on opposite sides of the battery stack to collect the current (lateral current collectors) or on adjacent sides. The connections are metallized using techniques known to those skilled in the art, preferably by immersion in a conductive epoxy resin and / or a molten tin bath. Preferably, the terminations are made, near the cathodic and anodic connections, of a first stack of layers successively comprising a first layer of a graphite-filled material, preferably graphite-filled epoxy resin, and a second layer comprising metallic copper obtained from an ink loaded with copper nanoparticles deposited on the first layer.This first stack of terminations is then sintered by infrared flash lamp so as to obtain a covering of the cathodic and anodic connections by a layer of metallic copper.

[0114] Depending on the final use of the battery, the terminations may additionally comprise a second stack of layers arranged on the first stack of terminations successively comprising a first layer of a tin-zinc alloy deposited, preferably by dipping in a bath of molten tin-zinc, in order to ensure the sealing of the battery at lower cost and a second layer based on pure tin deposited by electrodeposition or a second layer comprising an alloy based on silver, palladium and copper deposited on this first layer of the second stack.

[0115] The terminations allow the electrical connections to be made alternately positive and negative on each of the ends. These terminations allow the electrical connections to be made in parallel between the different battery elements. For this, only the cathode connections come out on one end, and the anode connections are available on another end.

Claims

1. Claims A method of manufacturing a battery, said battery comprising at least one anode (3) and at least one cathode (1), arranged one above the other in an alternating manner, said battery (100) comprising longitudinal edges (103,104) and lateral edges (101,102), wherein the anode (3) comprises - a current collector substrate, - at least one anode layer, and - optionally a layer of an electrolyte material or a separator impregnated with an electrolyte, and the cathode (1) comprises - a current collector substrate, - at least one cathode layer, and - optionally a layer of an electrolyte material or a separator impregnated with an electrolyte such that the battery successively comprises at least one anode layer, at least one layer of an electrolyte material or of a separator impregnated with an electrolyte, and at least one cathode layer, each anode (3) comprising an anode connection zone, located in the vicinity of a first lateral edge of the battery, while each cathode (1) comprises a cathode connection zone, located on a second lateral edge of the battery, opposite said first edge, said manufacturing method comprising: - supplying a stack (I) of alternating sheets, this stack comprising first sheets or anode sheets each of which is intended to form an anode layer of several batteries, as well as second sheets or cathode sheets each of which is intended to form a cathode layer of several batteries, each anode sheet comprising at least one anode slot (34) and each cathode sheet comprising at least one cathode slot (14), said anode and cathode slot respectively comprising two longitudinal parts (16, 36) at least partly superimposed, intended to delimit the longitudinal edges (103, 104) of the battery, as well as a lateral part (18, 38) connecting said two longitudinal parts longitudinal, the lateral part of the anode slot (38) and the lateral part of the cathode slot (18) extend mutually offset, said slots being through, - carrying out a heat treatment and / or a mechanical compression of the stack of alternating sheets previously supplied, the stack of anode and cathode sheets is then coated and then cut by any suitable means along the cutting lines D'n and Dn so as to expose the anode and cathode connections and to obtain unit batteries; the two cuts (Dn, D'n) extend at least partially inside said slots, the first cut extending between the lateral part of the anode slot and the facing end of the longitudinal parts, while the second cut extends between the lateral part of the cathode slot and the facing end of the longitudinal parts.

2. Method according to claim 1, characterized in that, after obtaining the unit batteries whose anode and cathode connections are exposed, the stack is impregnated with a phase carrying lithium ions such as liquid electrolytes or an ionic liquid containing lithium salts, said phase carrying lithium ions penetrating into the battery by capillarity.

3. Method according to claim 2, characterized in that the stack of anode sheets and cathode sheets is covered with a sequence, preferably z sequences, of an encapsulation system comprising: - a first covering layer, preferably chosen from parylene, F-type parylene, polyimide, epoxy resins, silicone, polyamide and / or a mixture thereof, deposited on the stack of anode and cathode sheets, - a second covering layer composed of an electrically insulating material, deposited by atomic layer deposition on said first covering layer, this sequence can be repeated z times with z > 1.

4. Method according to claim 2 or the claims, characterized in that the terminations of the battery are produced by successively depositing - a first layer of a graphite-filled material, preferably based on graphite-filled epoxy resin, - a second dense layer of metallic copper arranged on the first layer of the termination system, and - optionally, a third layer based on a tin-zinc alloy of tin, arranged on the second layer of the termination system, - optionally, a fourth layer based on tin or based on an alloy of silver, palladium and copper, arranged on the third layer of the termination system.

5. Method according to any one of claims 1 to 4, characterized in that the two cuts (Dn, D'n) are made through at least a majority of the anodes and cathodes, in particular through all of the anodes and cathodes.

6. Method according to claim 5, characterized in that the distances between each cutout and the opposite ends of the longitudinal parts are identical.

7. Method according to claim 6, characterized in that its distances are between 0.05 mm and 2 mm.

8. Method according to any one of claims 1 to 7, characterized in that each slot has an overall H shape, the longitudinal parts forming the main vertical recesses of the H, while the lateral part forms the channel of the H.

9. Method according to any one of claims 1 to 8, characterized in that each lateral part of the slots delimits a space free of any electrode material, electrolyte and / or current collector substrate connecting the opposite lateral edges of the battery, said free space separating, for each anode and each cathode, a main body from a secondary body.

10. Method according to claim 9, characterized in that the width of the lateral part is between 0.05 mm and 2 mm.

11. Method according to any one of claims 1 to 10, characterized in that each sheet belonging to said stack comprises several slit lines arranged next to each other, and in that the two cuts are made through all the slits of the same line.

12. Method according to any one of claims! to 11, characterized in that each sheet comprises several rows of slots arranged one below the other.

13. Method according to claim 12, characterized in that the distance separating adjacent cutouts, made in neighboring lines, is between 0.05 mm and 5 mm.

14. Method according to one of claims 12 or 13, characterized in that the number of lines is between 10 and 500, while the number of rows is between 10 and 500.

15. Battery obtained according to the method of any one of claims 1 to 14, characterized in that each anode and each cathode comprises a respective main body (111, 131), separated from a respective secondary body (112, 132) by a free space (113, 133) of any electrode material and current collector substrate, said free space connecting the opposite longitudinal edges (103, 104) of the battery.

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