GB2554860A

GB2554860A - Thin printed battery

Info

Publication number: GB2554860A
Application number: GB1616835.3A
Authority: GB
Inventors: Prakash Deep; Ali Moazzam; Engler Bjorn
Original assignee: Saralon GmbH
Current assignee: Saralon GmbH
Priority date: 2016-10-04
Filing date: 2016-10-04
Publication date: 2018-04-18
Also published as: GB201616835D0

Abstract

A thin battery 400 with a top foil 410 with a first and second opening 413, 414. The middle foil 430 has an anode terminal with a first conducting layer 437 and cathode terminal with second conducting layer 438, with first and second cuts 433, 434 around the terminals, allowing them to be pushed up through the first and second openings by a first and second push-up layer 453, 454 on the bottom foil 450, such that a portion of the first and second terminal conducting layers 437b, 438b face through the first and second openings. At least two battery cells are connected in series with at least one anode layer 415 and one cathode layer 416 on the first surface 412 of the top foil 410 connected by first and second connecting conducting layers 417, 418 to the first and second terminals 437, 438. Cathode and anode layers 455, 456 may be provided opposite the first surface, with separators 421, 422, 461, 462 between with electrolytes 423, 463, 424, 464 between them. Current collector layers 419, 459 may be used. First and second adhesive layers 441, 442 e.g. pressure, water, heat, or UV activated, may be placed on the terminals. The pushing-up arrangement is designed to avoid difficulties connecting terminals (fig 1A, fig 2A vs. fig 3B) for a laminate printing method (fig 5).

Description

(54) Title ofthe Invention: Thin printed battery

Abstract Title: Thin printable battery with terminals in middle foil projected from bottom foil through top foil, and cells arranged between the top and bottom foils (57) A thin battery 400 with a top foil 410 with a first and second opening 413, 414. The middle foil 430 has an anode terminal with a first conducting layer 437 and cathode terminal with second conducting layer 438, with first and second cuts 433, 434 around the terminals, allowing them to be pushed up through the first and second openings by a first and second push-up layer 453, 454 on the bottom foil 450, such that a portion of the first and second terminal conducting layers 437b, 438b face through the first and second openings. At least two battery cells are connected in series with at least one anode layer 415 and one cathode layer 416 on the first surface 412 of the top foil 410 connected by first and second connecting conducting layers 417, 418 to the first and second terminals 437, 438. Cathode and anode layers 455, 456 may be provided opposite the first surface, with separators 421,422, 461,462 between with electrolytes 423, 463, 424, 464 between them. Current collector layers 419, 459 may be used. First and second adhesive layers 441,442 e.g. pressure, water, heat, or UV activated, may be placed on the terminals. The pushing-up arrangement is designed to avoid difficulties connecting terminals (fig 1A, fig 2A vs. fig 3B) for a laminate printing method (fig 5).

FIGURE 4

1/5

FIGURE. ΙΑ 1 (Prior art)

FIGURE IB

2/5

FIGURE 2A (Prior art)

272 _z 270

FIGURE 2C

3/5

300

FIGURE 3 A

FIGURE 3B

4/5

FIGURE 4

5/5

580 and 581: Printing anode current collector layer s (419, 420) and cathode current collector layer s (420, 459).

585: Printing connecting conducting layers (417, 418), terminal conducting layer s (437, 438) and conducting layers (459).

Figure 5

-1TITLE

Thin printed battery

CROSS-RELATION TO OTHER APPLICATIONS [0001] None

FIELD OF THE INVENTION [0002] The present disclosure relates to a thin printed battery having a plurality of layers disposed between two foils, in which the layers are produced by printing methods using functional inks.

BACKGROUND OF THE INVENTION [0003] The demand for thin battery is increasing as the demand for smart and intelligent packages are also increasing. As used in this disclosure, the term “thin battery” refers to a battery, which comprises a plurality of layers with a total maximum thickness of 1 mm, including the foil thickness. Printing machines have been known for centuries for printing colour inks and are available all over the world. The same existing printing machines can also be used to print electronic devices e.g. battery, by replacing colour inks with so-called functional inks. The terms “print,” “printability,” “printing,” “printable” and “printed” as used in this disclosure refer to production methods using the functional inks. More specifically, these production methods include, but are not limited to, screen-printing, stenciling, flexography, gravure, off-set and ink-jet printing. These printing methods can be roll-to-roll or sheet-fed or manual. The term “ink” as used in this disclosure refers to a material that is in liquid or semisolid or paste form. It will be understood that, after printing of an ink on a surface, a drying or curing process may be required to convert the ink into a solid or a gel form. Typically, heat and/or radiation are used for the drying or curing processes. The drying or curing processes can be also self-activated.

[0004] The thin batteries produced by printing methods, as used in this disclosure refer to primary or secondary batteries. In prior art there are different kind of thin batteries known e.g. US 8574742 B2, US 8119278 B2, US 6838209 B2 and US 6485862 BI. In most of the cases, battery unit cells are laminated between two foil as shown in Figure 1 and Figure 2. In order to electrically accesses the battery unit cells, which are laminated between foils, conducting

-7terminal layers are used. These conducting terminal layers are used to connect the battery to an outside circuit. Figure 1A and Figure 2 A show the structures of two prior art thin batteries with two different conducting terminal layers. In Figure 1 A, the battery 100 comprises two foils 110 and 150. Cathode, anode, separator and electrolyte layers are sandwiched between the top foil 110 and the bottom foil 150. The top foil 110 comprises a first opening 113 and a second opening 114. A first terminal conducting layer 137 and a second terminal conducting layer 138 are used for electrically connecting the battery to an outside circuit. A portion of the first terminal conducting layer 137 works as anode terminal 137b of the battery 100. A portion of the second terminal conducting layer 138 works as cathode terminal 138b of the battery 100. Figure IB shows a cross section view of the battery 100, placed on a surface 171 of a substrate 170. The surface 171 comprises two conducting layers to connect the battery cathode terminal 138b and the anode terminal 137b. The Figure IB shows that the cathode terminal 138b of the battery 100 faces a conducting layer 172. The problem in this setup is that the thickness of the foil 110 is hindering the cathode terminal 138b to touch the conducting layer 172. In order to make electrical contacts with the battery 100, a thick layer of conducting glue are filled in the opening 114. From production point of view, this is not an easy process.

[0005] In Figure 2A, a battery 200 comprises a top foil 210 and a bottom foil 250. Cathode, anode, separator and electrolyte layers are sandwiched between the top foil 210 and the bottom foil 250. The top foil 210 is smaller than the bottom foil 250. A first terminal conducting layer 237 and a second terminal conducting layer 238 are provided on a second surface 251 of the bottom foil 250 to bring electrical connections from the battery unit cells to outside. A portion of the first terminal conducting layer 237 works as anode terminal 237b of the battery 200. A portion of the second terminal conducting layer 238 works as cathode terminal 238b of the battery 200. Figure 2B and Figure 2C show two different ways to connect the battery 200 on to a substrate 270. Figure 2B and Figure 2C show cross sectional view of the battery 200 on a surface 271 of the substrate 270. In Figure 2B, the conducting layer 272 provided on the surface 271 is facing the cathode terminal 238b of the battery 200. It can be seen that the cathode terminal 238b of the battery 200 is not touching the conducting layer 272 and they are separated by a gap. In order to connect the cathode terminal 238b to the conducting layer 272, the gap is filled by a thick layer of conducting glue. In Figure 2C, the cathode terminal 238b of the battery 200 is connected to the conducting layer 271 through a conducting adhesive tape. In both cases, fixing a thin battery 200 on a substrate 270 is a difficult task from the production point of view.

-3Therefore, there is a need to develop a thin battery that can easily be fixed on a substrate and can easily electrically connects to printed conducting layers on the substrate.

SUMMARY OF THE INVENTION [0006] The present invention relates to a thin battery. The thin battery comprises a top foil, a bottom foil and a middle foil. The top foil comprises a first surface, a first opening and a second opening. The bottom foil comprises a second surface. The middle foil comprises a third surface facing the first surface and a fourth surface facing the second surface. Two or more battery unit cells are connected in series and are provided between the top foil and the bottom foil such that at least one anode layer and at least one cathode layer are printed on the first surface. Each battery unit cell comprises an anode current collector layer, a cathode current collector layer, an anode layer, a cathode layer, at least one separator layer and at least one electrolyte layer. A first terminal conducting layer and a second terminal conducting layer are printed on the third surface, wherein a portion of the first terminal conducting layer is facing the first opening and a portion of the second terminal conducting layer is facing the second opening. A first cut and a second cut are provided on the middle foil, wherein the first cut is around a portion of a perimeter of the first terminal conducting layer and the second cut is around a portion of a perimeter of the second terminal conducting layer. A first connecting conducting layer and a second connecting conducting layer printed on the first surface, wherein the first connecting conducting layer connects the first terminal conducting layer to one of the at least one anode layer and the second connecting conducting layer connects the second terminal conducting layer to one of the at least one cathode layer. A first push-up layer and a second push-up layer are printed on the second surface, wherein the first push-up layer pushes a portion of the first cut into the first opening and the second push-up layer pushes a portion of the second cut into the second opening.

BRIEF DESCRIPTION OF THE DRAWINGS [0007] FIG. 1A is a prior art thin battery.

[0008] FIG. IB is a cross sectional view of a prior art thin battery on a substrate.

-4[0009] FIG. 2A is another prior art thin battery.

[00010] FIG. 2B is a cross sectional view of a prior art thin battery on a substrate.

[00011] FIG. 2C is a cross sectional view of a prior art thin battery on a substrate.

[00012] FIG. 3A is a thin battery, in accordance with an aspect of the present invention.

[00013] FIG. 3B is a thin battery on a substrate, in accordance with an aspect of the present invention.

[00014] FIG. 4 is an exploded view of a thin battery, in accordance with an aspect of the present invention.

[00015] FIG. 5 is a flow chart showing a manufacturing process to produce a thin battery according to one exemplary embodiment of the present disclosure.

DETAIFED DESCRIPTION OF THE PREFERRED EMBODIMENTS [00016] The invention will now be described in detail. Drawings and examples are provided for better illustration of the invention. It will be understood that the embodiments and aspects of the invention described herein are only examples and do not limit the protector’s scope of the claims in any way. The invention is defined by the claims and their equivalents. It will be understood that features of one aspect or embodiment of the invention can be combined with the feature of a different aspect or aspects and/or embodiments of the invention.

[00017] The present invention is about a thin printed battery. Figure 3 A shows the thin battery 300 according to an aspect of the present invention. The thin battery 300 comprises three foils - a top foil 310, a middle foil 330 and a bottom foil 350. These foils can be made of plastic or paper or textile. They can be mechanically flexible or mechanically rigid. They can be optically transparent or semi-transparent or opaque. They can be made of a single material or a laminate of different materials. The three foils can be of same thickness or of different thicknesses. In a non-limiting aspect, the thickness of the top foil 310 is in the range of 50 micrometers to 300 micrometers. In a non-limiting aspect, the thickness of the middle foil 330 is in the range of 50

-5micrometers to 300 micrometers. In a non-limiting aspect, the thickness of the bottom foil 350 is in the range of 50 micrometers to 300 micrometers. The top foil 310 comprises two openings - a first opening 313 and a second opening 314. A first cut 333 and a second cut 334 are provided on the middle foil 330. A portion 333a of the first cut 333 is inserted into the first opening 313. A portion 334a of the second cut 334 is inserted into the second opening 314. An anode terminal 337b is provided on the portion 333a of the first cut 333. The anode terminal 337b is a part of a first terminal conducting layer 337. A cathode terminal 338b is provided on the portion 334a of the second cut 334. The cathode terminal 338b is a part of a second terminal conducting layer 338. A first conducting adhesive layer 341 is provided on top of the anode terminal 337b. A second conducting adhesive layer 342 is provided on top of the cathode terminal 338b. In a non-limiting aspect, the conductive adhesive layers 341 and 342 can be pressure sensitive conducting layers. In another non-limiting aspect, the conductive adhesive layers 341 and 342 can be heat activated conductive adhesive layers. In another non-limiting aspect, the conductive adhesive layers 341 and 342 can be UV activated conductive adhesive layers. In another non-limiting aspect, the conductive adhesive layers 341 and 342 can be water activated conductive adhesive layers. Figure 3B shows a cross sectional view of the battery 300, placed on a surface 371 of a substrate 370. A conducting layer 372 provided on the surface 371 is facing the cathode terminal 338b of the battery 300. The portion 334a of the second cut 334 on the middle foil 330 raises the level of the cathode terminal 338b such that the cathode terminal 338b is in physical contact and hence in electrical contact with the conducting layer 372 through the second conducting adhesive layer 342. An advantage of the battery 300 is that it can easily be electrically connected to an external circuit, just by placing the battery 300 on a substrate 370 at an appropriate position. Another advantage of the battery 300 is that adhesion of the anode and cathode terminals of the battery on the conducting layers of the substrate do not become weaker by the vibration of the substrate. The first cut 333 and the second cut 334 are made of flexible material, as the middle foil 330 is made of plastic. The flexible nature of the first cut 333 and the second cut 334 makes the thin battery 300 to withstand vibration. In one non-limiting aspect, the substrate 370 can be made of paper and that can be a part of a package. The package needs to be transported, that causes mechanical vibration of the package. The adhesion of the battery can withstand a certain degree of mechanical vibration because of spring-like characteristic of the first cut 333 and the second cut 334. The first cut 333 and the second cut 334 are made of the same material as the middle foil 330 and the middle foil is made of flexible plastic. The flexibility of the first cut 333 and the second cut 334 provides them spring-like characteristics.

-6[00018] Figure 4 is an exploded view of a thin battery 400, in accordance with an aspect of the present invention. The thin battery 400 comprises a top foil 410, a middle foil 430 and a bottom foil 450. The top foil 410 comprises a first surface 412 and a fifth surface 411. The bottom foil

450 comprises a second surface 451 and a sixth surface 452. The middle foil 430 comprises a third surface 431 and a fourth surface 432. The third surface 431 is facing the first surface 412 of the top foil 410. The fourth surface 432 is facing the second surface 451 of the bottom foil 450. The top foil 410 comprises a first opening 413 and a second opening 414. The area of each of the first opening 413 and the second opening414 is in the range of 0.25 cm² to 10 cm². The first opening 413 and the second opening 414 can be of any shape e.g. rectangular, circular, elliptical etc. In a non-limiting aspect, an edge 410a of the top foil 410 is physically connected to an edge 430a of the middle foil 430 and an another edge 410b of the top foil 410 is physically connected to an edge 450b of the bottom foil 450.

[00019] On the first surface 412 of the top foil 410 are printed at least one anode current collector layer 419 and at least one cathode current collector layer 420. On the second surface

451 of the bottom foil 450 are printed at least one anode current collector layer 460 and at least one cathode current collector layer 459. In a non-limiting aspect, the anode current collecting layers and the cathode current collecting layers are based on carbon particles. On top of the anode current collecting layer 419 is printed at least one anode layer 415. On top of the anode current collecting layer 460 is printed at least one anode layer 456. On top of the cathode current collecting layer 420 is printed at least one cathode layer 416, facing the at least one anode layer 456. On top of the cathode current collecting layer 459 is printed at least one cathode layer 455, facing the at least one anode layer 415. The anode layer 415 and 456 are printed by using an anode functional ink which comprises substantially, but is not limited to, at least one anode active powder, at least one polymeric binder and at least one solvent. The cathode layer 416 and 455 are printed by using a cathode functional ink which comprises substantially, but is not limited to, at least one anode active powder, at least one polymeric binder and at least one solvent. The anode active powder and the cathode active powder of the thin battery can be selected from an appropriate electrochemical-couple, such as, but not limited to, a zincmanganese dioxide, lithiummanganese oxide-titanium dioxide, lithium manganese oxidevanadium oxide, etc. In one non-limiting example, the polymeric binder is water soluble e.g polyethyleneoxide, polyvinylalcohol, polyvinylpyrrolidone etc. In another non-limiting

-Ί example, the polymeric binder is water insoluble e.g. polystyrene, poly(methyl methacrylate) PMMA, ethyl cellulose, polyvinylidene fluoride etc.

[00020] The anode layer 415 and 456 and/or the cathode layer 416 and 455 can further comprise electrically conducting particles, which enhance movement of electrons inside the layer. In one non-limiting example, the electrically conducting particles can be graphite, carbon black, carbon nanotube, graphene etc. The anode functional ink and the cathode functional ink can further comprise additives to enhance printability of the inks, to improve surface adhesion, to improve dispersion of the particles in the ink, to adjust viscosity, to increase battery voltage, to increase current density and to lower gas evolution. In one non-limiting example, the anode layer and the anode current collecting layer are made of the same materials. That means a single layer will serve the dual purpose of working as a battery anode and transferring the generated current to outside of the battery unit cell. In one non-limiting example, the cathode layer and the cathode current collecting layer are made of the same materials. That means a single layer will serve the dual purpose, working as a battery cathode and transferring the generated current to outside of the battery unit cell. On top of the anode layers 415 and 456 are printed separator layers 421 and 462, respectively. On top of the cathode layers 416 and 455 are printed separator layers 422 and 461, respectively. The separator layers 421, 462, 422 and 461 are produced by printing a separator functional ink. The separator functional ink comprises, but not limited to, cellulose fibers, solvent and binders. The binders are used in the separator functional ink to interconnect cellulose fibers after the separator functional ink is printed. On top of at least one of the separator layers 421, 462, 422 and 461 is printed at least one electrolyte layer 423, 424, 463 and 464. In a non-limiting aspect, the electrolyte layers can be printed on a portion of the separator layers. The electrolyte layers substantially comprise, but is not limited to, at least one solvent and at least one electrolyte salt. The electrolyte salt can be selected based on electrochemistry of the battery. For example, for a zinc-manganese dioxide battery the electrolyte salt can be a zinc chloride salt and for a lithium manganese oxide-titanium dioxide battery the electrolyte salt can be lithium chloride or lithium nitrate or lithium sulphate or a mixture of different lithium salts. The at least one anode layer 415 is electrochemically connected to the at least one cathode layer 455 through the separator layers 421 and 461 and the electrolyte layers 423 and 463 such that at least one battery unit cell is created. The at least one cathode layer 416 is electrochemically connected to the at least one anode layer 456 through the separator layers 422 and 462 and the electrolyte layers 424 and 464 such that at least one another battery unit cell is created. At least two openings 435 and 436 are provided on the

-8middle foil 430 which function as the boundary of the unit cell batteries. At least one conducting layer 459, printed on the surface 451 or on the surface 412 or on both the surfaces 412 and 451 connect one battery unit cell to another battery unit cell to establish a series connection of the batteries. In a non-limiting aspect, the battery comprises two battery unit cells. In another nonlimiting aspect, the battery comprises four battery unit cells. In another non-limiting aspect, the battery comprises more than four battery unit cells.

[00021] A first terminal conducting layer 437 and a second terminal conducting layer 438 are printed on top of the third surface 431 of the middle foil 430. A first cut 433 is made on the middle foil 430 around a portion of a perimeter of the first terminal conducting layer 437. A second cut 434 is made on the middle foil 430 around a portion of a perimeter of the second terminal conducting layer 438. A first connecting conducting layer 417 is printed on the first surface 412 of the top foil 410. The first connecting conducting layer 417 electrically connect one of the anode layer 415 to the first terminal conducting layer 437. An end 417a of the first connecting conducting layer 417 is in electrical contact with an end 437a of the first terminal conducting layer 437. The second connecting conducting layer 418 electrically connects one of the cathode layer 416 to the second terminal conducting layer 438. An end 418a of the second connecting conducting layer 418 is in electrical contact with an end 438a of the second terminal conducting layer 438. A first push-up layer 453 and a second push-up layer 454 are printed on the second surface 451 of the bottom foil 450. The first push-up layer 453 pushes a portion 433a of the first cut 433 into the first opening 413, such that the level of the plane of the first cut is raised from the plane of the third surface 431. Hence, the plane of a portion 437b of the first terminal conducting layer 437 is also raised. The portion 437b of the first terminal conducting layer 437 is called here the anode terminal. The second push-up layer 454 pushes a portion 434a of the second cut 434 into the second opening 414, such that the level of the plane of the second cut is raised from the plane of the third surface 431. Hence, the plane of a portion 438a of the second terminal conducting layer 438 is also raised. The portion 438a of the second terminal conducting layer 438 is called here the cathode terminal. In a non-limiting example, the thickness of the first push-up layer 453 and the second push-up layer 454 are in the range of 50 micrometers to 300 micrometers. A first conducting adhesive layer 441 is provided on top of the anode terminal 437b. A second conducting adhesive layer 442 is provided on top of the cathode terminal 438b. In a non-limiting aspect, the conductive adhesive layers 441 and 442 can be pressure sensitive conducting adhesive layers. In another non-limiting aspect, the conductive adhesive layers 441 and 442 can be heat activated conductive adhesive layers. In

-9another non-limiting aspect, the conductive adhesive layers 441 and 442 can be UV activated conductive adhesive layers. In another non-limiting aspect, the conductive adhesive layers 441 and 442 can be water activated conductive adhesive layers. At least one non-conducting adhesive layer (not shown in the Figure 4) is printed on a portion of at least one of the first surface 412, the second surface 451, the third surface 431 and the fourth surface 432 such that the battery unit cells are sandwiched between the top foil 410 and the bottom foil 450. In a nonlimiting aspect, the at least one adhesive layer can be a pressure sensitive adhesive. In another non-limiting aspect, the at least one adhesive layer can be a heat sensitive adhesive.

[00022] The thin battery 400 can be produced according to the following exemplary process, as illustrated in Figure 5:

[00023] In the step 579, a top foil 410, a bottom foil 450 and a middle foil 430 are provided. In a non-limiting aspect, an edge 410a of the top foil 410 is physically connected to an edge 430a of the middle foil 430 and an another edge 410b of the top foil 410 is physically connected to an edge 450b of the bottom foil 450.

[00024] In the step 580, at least one anode current collector layer 419 and at least one cathode current collector layer 420 are printed on a first surface 412 of the top foil 410.

[00025] In the step 581, at least one anode current collector layer 460 and at least one cathode current collector layer 459 are printed on a second surface 451 of the bottom foil 450. In a nonlimiting aspect, the step 580 and the step 581 can be done by a single printing process.

[00026] In the step 582, at least one anode layer 415 and at least one anode layer 456 are printed on top of the at least one anode current collector layer 419 and on the top of the at least one anode current collector layer 460, respectively.

[00027] In the step 583, at least one cathode layer 416 and at least one cathode layer 455 are printed on top of the at least one cathode current collector layer 420 and on the top of the at least one cathode current collector layer 459, respectively.

-10[00028] In the step 584, separator layers 421, 422, 461 and 462 are printed on top of the at least one anode layer 415, the at least one cathode layer 416, the at least one cathode layer 455 and the at least one anode layer 456, respectively.

[00029] In the step 585, a first connecting conducting layer 417 and a second connecting conducting layer 418 on the first surface 412, a first terminal conducting layer 437 and a second terminal conducting layer 438 on the third surface 431 and at least one conducting layer 459 on at least one of the first surface 412 and the second surface 451 are printed.

[00030] In the step 586, a first push-up layer 453 and a second push-up layer 454 are printed on the second surface 651.

[00031] In the step 587, a first conducting adhesive layers 441 and a second conductive adhesive layer 442 are printed on the anode terminal layer 437b and on the cathode terminal layer 438b, respectively.

[00032] In the step 588, at least one non-conducting adhesive layer is printed on at least a portion of at least one of the first surface (412), the second surface (451), the third surface (431) and the fourth surface (432) are printed.

[00033] In the step 589, a first opening 413 and a second opening 414 of the top foil 410, at least two openings 435 and 436 on the middle foil 430 and a first cut 433 and a second cut 433 on the middle foil 430 are provided. The first cut 433 is around a portion of a perimeter of the first terminal conducting layer 437 and the second cut 434 is around a portion of a perimeter of the second terminal conducting layer 438.

[00034] In the step 590, at least one electrolyte layer 423, 424, 463 and 464 are printed on at least one of the separator layers 421, 422, 461 and 462.

[00035] In the step 591, the top foil 410, the middle 430 and the bottom foil 450 are laminated together such that the lamination process causes the first push-up layer 453 to push a portion 433 a of the first cut 433 into the first opening 413 and the second push-up layer 454 to push a portion 434a of the second cut 434 into the second opening 414. The lamination process also causes an end 417a of first connecting conducting layer 417 to electrically connects an end 437a

-11of the first terminal conducting layer 437 and an end 418a of second connecting conducting layer 418 to electrically connects an end 438a of the second terminal conducting layer 438. The lamination process creates at least two battery unit cells such that each battery unit cell is a sandwich structure of an anode current collector layer, an anode layer, separator layers, electrolyte layers, cathode layer and cathode current collector layer.

[00036] In a non-limiting aspect, the steps (579 to 591) mentioned above can further comprises printed of additional layers on any of the top foil (410), the bottom foil (450) and the middle foil (430). The printing of the additional layers can be done before the step 579 or after the step 591 or between the step 579 and the step 591. Is it understood that after printing the functional inks, the printed layer might need to be solidified. This solidification can be done by drying out the solvent present in the printed layer or by curing the printed layer by electromagnetic radiation e.g. UV, infrared etc. In a non-limiting aspect, the steps (579 to 591) mentioned above can be in a different order.

Claims

1. A thin battery (400), comprising:

a top foil (410) comprising a first surface (412), a first opening (413) and a second opening (414);

a bottom foil (450) comprising a second surface (451);

a middle foil (430) comprising a third surface (431) facing the first surface (412) and a fourth surface (432) facing the second surface (451);

at least two battery unit cells connected in series, provided between the top foil (410) and the bottom foil (450), wherein at least one anode layer (415) and at least one cathode layer (416) are provided on the first surface (415);

a first terminal conducting layer (437) and a second terminal conducting layer (438) provided on the third surface (431), wherein a portion (437b) of the first terminal conducting layer (437) is facing the first opening (413) and a portion (438b) of the second terminal conducting layer (438) is facing the second opening (414);

a first cut (433) and a second cut (434) on the middle foil (430), wherein the first cut (433) is around a portion of a perimeter of the first terminal conducting layer (437) and the second cut (434) is around a portion of a perimeter of the second terminal conducting layer (438); a first connecting conducting layer (417) and a second connecting conducting layer (418) provided on the first surface (412), wherein the first connecting conducting layer (417) connects the first terminal conducting layer (437) to one of the at least one anode layer (415) and the second connecting conducting layer (418) connects the second terminal conducting layer (438) to one of the at least one cathode layer (416); and a first push-up layer (453) and a second push-up layer (454) provided on the second surface (451), wherein the first push-up layer (453) pushes a portion (433a) of the first cut (433) into the first opening (413) and the second push-up layer (454) pushes a portion (434a) of the second cut (434) into the second opening (414).

2. The thin battery (400) as claimed in claim 1, wherein the at least two battery unit cells further comprise at least one cathode layer (455) and at least one anode layer (456) provided on the second surface (451), wherein the at least one cathode layer (455) facing the at least one anode layer (415) and the at least one anode layer (456) facing the at least one cathode layer (416).

-133. The thin battery (400) as claimed in claims 1 and 2, wherein at least one separator layer (421) is provided on the at least one anode layer (415), at least one separator layer (422) is provided on the at least one cathode layer (416), at least one separator layer (461) is provided on the at least one cathode layer (455) and at least one separator layer (462) is provided on the at least one anode layer (456).

4. The thin battery (400) as claimed in claims 1, 2 and 3, wherein at least one electrolyte layer (423, 463) sandwiched between the at least one separator layer (421) and the at least one separator layer (461) and at least one electrolyte layer (424, 464) sandwiched between the at least one separator layer (422) and the at least one separator layer (462).

5. The thin battery (400) as claimed in claim 1, wherein the middle foil (430) further comprises at least two openings (435, 436), wherein each of the at least two openings (435, 436) functions as a boundary for a battery unit cell.

6. The thin battery (400) as claimed in claim 1, wherein each of the first push-up layer (453) and the second push-up layer (454) comprises more than one printed layers.

7. The thin battery (400) as claimed in claim 1, wherein at least one anode current collector layer (419) provided between the first surface (412) and the at least one anode layer (415), at least one cathode current collector layer (420) provided between the first surface (412) and the at least one cathode layer (416), at least one anode current collector layer (460) provided between the second surface (451) and the at least one anode layer (456) and at least one cathode current collector layer (459) provided between the second surface (451) and the at least one cathode layer (455).

8. The thin battery (400) as claimed in claim 1, wherein a first conducting adhesive layer (441) provided on a portion (437b) of the first terminal conducting layer (437) and a second conducting adhesive layer (442) provided on a portion (438b) of the second terminal conducting layer (438).

-149. The thin battery (400) as claimed in claims 1 and 8, wherein the first conducting adhesive layer (441) and the second conducting adhesive layer (442) are pressure sensitive conducting adhesive.

10. The thin battery (400) as claimed in claims 1 and 8, wherein the first conducting adhesive layer (441) and the second conducting adhesive layer (442) are water activated conductive adhesive.

11. The thin battery (400) as claimed in claims 1 and 8, wherein the first conducting adhesive layer (441) and the second conducting adhesive layer (442) are heat activated conductive adhesive.

12. A method of producing a thin battery (400), comprising the steps of:

a. providing a top foil (410) comprising a first surface (412), a bottom foil (450) comprising a second surface (451) and a middle foil (430) comprising a third surface (431) facing the first surface (412) and a fourth surface (432) facing the second surface (451);

b. printing at least one anode layer (415) on the first surface (412) and at least one anode layer (456) on the second surface (451);

c. printing at least one cathode layer (416) on the first surface (412) and at least one cathode layer (455) on the second surface (451);

d. printing at least one separator layer (421) on the at least one anode layer (415), at least one separator layer (422) on the at least one cathode layer (416), at least one separator layer (461) on the at least one cathode layer (455) and at least one separator layer (462) on the at least one anode layer (456);

e. printing a first connecting conducting layer (417) and a second connecting conducting layer (418) on the first surface (412), a first terminal conducting layer (437) and a second terminal conducting layer (438) on the third surface (431) and at least one conducting layer (459) on at least one of the first surface (412) and the second surface (451).

f. printing a first push-up layer (453) and a second push-up layer (454) on the second surface (451);

g. printing a first conducting adhesive layer (441) on a portion (437b) of the first terminal conducting layer (437) and a second conductive adhesive layer (442) on a portion (438b) of the second terminal conducting layer (438);

-15h. printing at least one non-conducting adhesive layer on at least a portion of at least one of the first surface (412), the second surface (451), the third surface (431) and the fourth surface (432).

i. providing a first opening (413) and a second opening (414) on the top foil (410), at least two openings (435, 436) on the middle foil (430) and a first cut (433) and a second cut (434) on the middle foil (430), wherein the first cut (433) is around a portion of a perimeter of the first terminal conducting layer (437) and the second cut (434) is around a portion of a perimeter of the second terminal conducting layer (438);

j. printing at least one electrolyte layer (423, 424, 463, 464) on at least one of the at least one separator layer (421), the at least one separator layer (461), the at least one separator layer (422) and the at least one separator layer (462); and

k. laminating the top foil (410), the middle (430) and the bottom foil (450), wherein the lamination process causes the first push-up layer (453) to push a portion (433a) of the first cut (433) into the first opening (413), the second push-up layer (454) to push a portion (434a) of the second cut (434) into the second opening (414), an end (417a) of first connecting conducting layer (417) to electrically connects an end (437a) of the first terminal conducting layer (437) and an end (418a) of second connecting conducting layer (418) to electrically connects an end (438a) of the second terminal conducting layer (438).

13. The method of claim 12, further comprising the steps of providing at least one anode current collector layer (419) between the at least one anode layer (415) and the first surface (412), providing at least one anode current collector layer (460) between the at least one anode layer (456) and the second surface (451), providing at least one cathode current collector layer (420) between the at least one cathode layer (416) and the first surface (412) and providing at least one cathode current collector layer (459) between the at least one cathode layer (455) and the second surface (451).

14. The method of claim 12, further comprising the steps of solidifying at least one of the printed layer by at least one of drying step and curing step.

Intellectual

Property

Office

Application No: GB1616835.3 Examiner: Mr Robin Newman