Patent Application
20230198024
The present invention relates to the field of batteries, and more particularly to lithium-ion batteries. The invention concerns a new method of manufacturing batteries, and in particular lithium-ion batteries which have a new architecture which gives them an improved service life.
All-solid-state rechargeable lithium-ion batteries are known. WO 2016/001584 (I-TEN) describes a lithium-ion battery manufactured from anode foils comprising a conductive substrate successively covered with an anode layer and an electrolyte layer, and cathode foils comprising a conductive substrate successively covered with a cathode layer and an electrolyte layer; these foils are cut, before or after deposition, according to U-shaped patterns. These foils are then alternately stacked in order to constitute a stack of several unit cells. The patterns of cutting the anode and cathode foils are placed in a “head-to-tail” configuration so that the stack of the cathodes and anodes is laterally offset. Then an encapsulation system with a thickness of about ten microns is deposited on the stack and in the available cavities present within the stack. This encapsulation system ensures the rigidity of the structure at the cutting planes and protects the battery cell from the atmosphere. Once the stack has been made and encapsulated, it is cut along cutting planes to obtain unit batteries, with the exposure, on each of the cutting planes, of the cathode connection zones and the anode connection zones of the batteries. It is found that during these cuts, the encapsulation system can be torn off, resulting in a discontinuity in the sealing of the battery. It is also known to add terminations (i.e. electrical contacts) where these cathode and anode connection zones are apparent.
It appeared that this known solution may however have some drawbacks. Indeed, depending on the positioning of the electrodes, in particular the proximity of the edges of the electrodes for multilayer batteries and the cleanliness of the cuts, a leakage current may appear on the ends, typically in the form of a creeping short-circuit. This creeping short-circuit decreases the battery performance despite the use of an encapsulation system around the battery and around the cathode and anode connection zones. Moreover, there is sometimes an unsatisfactory deposition of the encapsulation system on the battery, in particular on the edges of the battery at spaces created by the lateral offsets of the electrodes on the edges of the battery.
The present invention aims at overcoming at least in part some drawbacks of the prior art which are mentioned above, in particular at obtaining rechargeable lithium-ion batteries with high energy density and high power density.
It aims in particular at increasing the production efficiency of rechargeable lithium-ion batteries with high energy density and high power density, and at making more efficient encapsulations at lower cost.
It aims in particular at proposing a method which reduces the risk of a creeping or accidental short-circuit and which allows manufacturing a battery having a low self-discharge.
It aims in particular at proposing a method which allows simply, reliably and quickly manufacturing a battery having a very long life service.
It also aims at proposing a method for manufacturing simple, fast and cost-effective batteries.
A first object of the invention is a battery for manufacturing at least one battery (1000), each battery comprising at least one anode entity (110) and at least one cathode entity (140), disposed one above the other in an alternating manner in a frontal direction (ZZ) of the battery (1000), in which battery, the anode entity (110) comprises: an anode current collector substrate (10), at least one anode layer (20), and possibly a layer of an electrolyte material (30) or a separator (31) impregnated with an electrolyte, and in which battery the cathode entity (140) comprises a cathode current collector substrate (40), at least one cathode layer (50), and possibly a layer of an electrolyte material (30) or a separator (31) impregnated with an electrolyte.
The battery (1000) has six faces, namely, two faces called front faces (F1, F2) which are mutually opposite, in particular mutually parallel, generally parallel to each anode entity (110) and, to each cathode entity (140), two faces called lateral faces (F3, F5) which are mutually opposite, in particular mutually parallel; and two faces called longitudinal faces (F4, F6), which are mutually opposite, in particular mutually parallel. Given that the first longitudinal face (F6) of the battery comprises at least one anode connection zone (1002) and that a second longitudinal face (F4) of the battery comprises at least one cathode connection zone (1006), the anode (1002) and cathode (1006) connection zones being laterally opposite, each anode entity (110) and each cathode entity (140) comprising a respective primary body (111, 141), separated from a respective secondary body (112, 142) by a free space (113, 143) of any material of electrode, electrolyte and current collector substrate.
When the battery comprises several free spaces (113), in the frontal direction (ZZ) of the battery: the free spaces formed between each primary body (111) and each secondary body (112) of each anode entity (110) are superimposed; the free spaces formed between each primary body (141) and each secondary body (142) of each cathode entity (140) are superimposed; and the free spaces of each anode entity (110) and each cathode entity (140) are not coincident.
The manufacturing method comprises: a) making a stack (I) comprising, in top view, x rows with x strictly greater than 1 as well as y line(s) with y greater than or equal to 1, so as to form a number (x*y) of batteries, this stack being formed by an alternating succession of strata (SA, SC) respectively cathode (SC) and anode (SA) strata, each cathode stratum (SC) being intended to form a number (x*y) of cathode entities (140) while each anode stratum (SA) is intended to form a number (x*y) of anode entities (110), each stratum (SA, SC) comprising a plurality of primary preforms (111′, 141′), respectively anode (111′) and cathode (141′) primary preforms, each of which is intended to form a respective primary body (111, 141), a plurality of secondary preforms (112′, 142′), respectively anode (112′) and cathode (142′) secondary preforms, each of which is intended to form a respective secondary body (112, 142), the primary preform (111′, 141′) and the secondary preform (112′, 142′) being mutually separated by a zone called empty zone (80″, 70″), which is intended to form at least one of the free spaces (113, 143), and when the battery comprises several free spaces (113), in the frontal direction (ZZ) of the battery; the empty zones (80″) of the different anode strata (SA) are superimposed; the empty zones (70″) of the different cathode strata (SC) are superimposed; and the empty zones (80″, 70″) of each anode stratum (SA) and each cathode stratum (SC) are not coincident.
The manufacturing method further comprises: b) carrying out a heat treatment and/or a mechanical compression of the stack (I) obtained in step a) so as to form a consolidated stack; and c) making a pair of main cuts (DYn, DY′n) between two adjacent empty zones (80″, 70″), in top view, so as to expose the anode connection zone (1002) and the cathode connection zone (1006), and to separate a given battery, formed from a given row (Rn), from at least one other adjacent battery, formed from at least one adjacent row (Rn+1).
According to a first embodiment, each stratum (SA, SC) is formed by a foil in one piece, the empty zones corresponding in particular to material falls in the foil (70, 80, 70′, 80′).
According to another embodiment, each stratum (SA, SC) is formed by a plurality of independent strips (A1, A2, An, C1, C2, Cn), the empty zones (113′, 143′) being defined between the edges (LA, LC) facing the adjacent strips.
According to a first variant of the invention, empty zones called small empty zones (80, 70) referred to as slots are made, each empty zone, called small empty zone, is intended to form a single free space.
According to a second variant of the invention, empty zones called large empty zones (80′, 70′) referred to as notches are made, each large empty zone being intended to form a plurality of free spaces in the same row, in particular all free spaces of the same row (Rn).
According to an advantageous feature of the invention, the empty zones (70, 70′, 80, 80′) have a rectangular shape, in particular an I-shape.
According to one feature of the invention, one makes after step b), during a step d), a pair of accessory cuts (DXn, DX′n) allowing separating a given line (Ln) from at least one adjacent line (Ln−1, Ln+1) belonging to the consolidated stack.
According to another feature of the invention, one carries out, during a step e), the impregnation of the consolidated stack obtained in step b) or the impregnation of the line (Ln) of batteries (1000) obtained in step d) when step d) is carried out, by a lithium ion carrier phase such as liquid electrolytes or an ionic liquid containing lithium salts, such that the separator layer (31) is impregnated with an electrolyte.
According to one feature of the invention, one carries out, before step c) and after step e) if the latter is carried out or else, if step e) is not carried out, after step d) if step d) is carried out or else, if steps e) and d) are not carried out, after step b), a step f) of encapsulation of the consolidated stack or the line (Ln) of batteries (1000), preferably, in which one covers, by an encapsulation system (95), the outer periphery of the stack (I) or the line (Ln) of batteries (1000), preferably the front faces of the stack (F1, F2) or the line (Ln) of batteries (FF1, FF2), the lateral faces (F3, F5, FF3, FF5) and the longitudinal faces (F4, F6, FF4, FF6) of the stack (I) or the line (Ln) of batteries (1000).
The encapsulation system (95) preferably comprises: optionally, at least one first cover layer, preferably selected from parylene, parylene type F, polyimide, epoxy resins, silicone, polyamide, sol-gel silica, organic silica and/or a mixture thereof, deposited on the outer periphery of the stack (I) or the line (Ln) of batteries (1000); optionally a second cover layer composed of an electrically insulating material deposited by deposition of atomic layers, on the outer periphery of the stack (I) or on the outer periphery of the line (Ln) of batteries (1000) or on the first cover layer; and at least one third waterproof cover layer, preferably having a water vapor permeance (WVTR) of less than 10−5 g/m2·d, this third cover layer being composed of a ceramic material and/or a low melting point glass, preferably a glass whose melting point is less than 600° C., deposited on the outer periphery of the stack (I) or on the outer periphery of the line (Ln) of batteries (1000), or the first cover layer. Given that a sequence of at least one second cover layer and at least one third cover layer can be repeated z times withz≥1 and deposited on the outer periphery of at least the third cover layer, and that the last layer of the encapsulation system is a waterproof cover layer, preferably having a water vapor permeance (WVTR) of less than 10−5 g/m2·d and being composed of a ceramic material and/or a low melting point glass.
According to another feature of the invention, after step c), a step g) is carried out in which one covers at least the anode connection zone (1002), preferably at least the first longitudinal face (F6) comprising at least the anode connection zone (1002), by an anode contact member (97′), capable of ensuring the electrical contact between the stack (I) and an outer conductive element, and in that one covers at least the cathode connection zone (1006), preferably at least the second longitudinal face (F4) comprising at least the cathode connection zone (1006), by a cathode contact member (97″) capable of ensuring the electrical contact between the stack (I) and an outer conductive element, step (i) comprising: the deposition on at least the anode connection zone (1002) and on at least the cathode connection zone (1006), preferably, on at least the first longitudinal face (F6) comprising at least the anode connection zone (1002), and on at least the second longitudinal face (F4) comprising at least the cathode connection zone (1006), of a first electrical connection layer of material loaded with electrically conductive particles, the first layer being preferably formed of polymeric resin and/or a material obtained by a sol-gel method loaded with electrically conductive particles.
Optionally, when the first layer is formed of polymeric resin and/or a material obtained by a sol-gel method loaded with electrically conductive particles, a drying step followed by a step of polymerisation of the polymeric resin and/or the material obtained by a sol-gel method; and the deposition, on the first layer, of a second electrical connection layer comprising a metal foil disposed on the first electrical connection layer.
Optionally, the deposition on the second electrical connection layer, of a third electrical connection layer comprising a conductive ink.
According to yet another feature of the invention, the cuts made in step d) when this step is carried out, and/or in step c), are performed by laser ablation, preferably in that all cuts made in step d) when this step is carried out, and/or in step c) are performed by laser.
The invention also relates to a battery (1000) comprising at least one anode entity (110) and at least one cathode entity (140), disposed one above the other in an alternating manner in a frontal direction (ZZ) to the main plane of the battery (1000), forming a stack (I), in which the anode entity (110) comprises: an anode current collector substrate (10), at least one anode layer (20), and possibly a layer of an electrolyte material (30) or a separator (31) impregnated with an electrolyte, and in which the cathode entity (140) comprises: a cathode current collector substrate (40), at least one cathode layer (50), and possibly a layer of an electrolyte material (30) or a separator (31) impregnated with an electrolyte.
The battery (1000) has six faces, namely, two faces called front faces (F1, F2) which are mutually opposite, in particular mutually parallel, generally parallel to each anode entity (110), to each cathode entity (140), to the anode current collector substrate(s) (10), to the anode layer(s) (20), to the layer(s) of an electrolyte material (30) or to the layer(s) of separator impregnated with an electrolyte (31), to the cathode layer(s) (50), and to the cathode current collector substrate(s) (40), two faces called lateral faces (F3, F5) which are mutually opposite, in particular mutually parallel, and two faces called longitudinal faces (F4, F6), which are mutually opposite, in particular mutually parallel.
Given that the first longitudinal face (F6) of the battery comprises at least one anode connection zone (1002) and that a second longitudinal face (F4) of the battery comprises at least one cathode connection zone (1006), the anode (1002) and cathode (1006) connection zones being laterally opposite, such that: each anode entity (110) and each cathode entity (140) comprises a respective primary body (111, 141), separated from a respective secondary body (112, 142) by a free space (113, 143) of any material of electrode, electrolyte and current collector substrate. When the battery comprises several free spaces (113), in a frontal direction (ZZ) to the main plane of the battery, the free spaces formed between each primary body (111) and each secondary body (112) of each anode entity (110) are superimposed, the free spaces formed between each primary body (141) and each secondary body (142) of each anode entity (110) are superimposed, and the free spaces of each anode entity (110) and each cathode entity (140) are not coincident.
The battery comprises an encapsulation system covering at least in part the outer periphery of the stack (I), the encapsulation system (95) covering the front faces of the stack (F1, F2), the lateral faces (F3, F5) and at least in part the longitudinal faces (F4, F6) such that only the anode (1002) and cathode (1006) connection zones, preferably, the first longitudinal face (F6) comprising at least the anode connection zone (1002), and the second longitudinal face (F4) comprising at least the cathode connection zone (1006), are not covered with the encapsulation system (95).
The encapsulation system (95) comprises: optionally, a first cover layer, preferably selected from parylene, parylene type F, polyimide, epoxy resins, silicone, polyamide, sol-gel silica, organic silica and/or a mixture thereof, deposited on at least part of the outer periphery of the stack (I), optionally a second cover layer composed of an electrically insulating material deposited by deposition of atomic layers, on at least part of the outer periphery of the stack (I), or on the first cover layer, at least one third waterproof cover layer, preferably having a water vapor permeance (WVTR) of less than 10−5 g/m2·d, this third cover layer being composed of a ceramic material and/or a low melting point glass, preferably a glass whose melting point is less than 600° C., deposited on at least part of the outer periphery of the stack (I), or on the first cover layer. Given that when the second cover layer is present, a succession of the second cover layer and the third cover layer can be repeated z times with z≥1 and deposited on the outer periphery of at least the third cover layer, the last layer of the encapsulation system being a waterproof cover layer, preferably having a water vapor permeance (WVTR) of less than 10−5 g/m2·d and being composed of a ceramic material and/or a low melting point glass.
According to an advantageous feature of the battery in accordance with the invention, the anode connection zone (1002), preferably the first longitudinal face (F6) comprising at least the anode connection zone (1002), is covered by an anode contact member (97′), and at least the cathode connection zone (1006), preferably the second longitudinal face (F4) comprising at least the cathode connection zone (1006), is covered by a cathode contact member (97″), given that the anode (97′) and cathode (97″) contact members are capable of ensuring the electrical contact between the stack (I) and an outer conductive element.
According to another feature of the battery in accordance with the invention, each of the anode (97′) and cathode (97″) contact members comprises: a first electrical connection layer, disposed on at least the anode connection zone (1002) and at least the cathode connection zone (1006), preferably on the first longitudinal face (F6) comprising at least the cathode connection zone (1002) and on the second longitudinal face (F4) comprising at least the cathode connection zone (1006), the first electrical connection layer comprising a material loaded with electrically conductive particles, preferably a polymeric resin and/or a material obtained by a sol-gel method, loaded with electrically conductive particles and even more preferably a polymeric resin loaded with graphite, and a second electrical connection layer comprising a metal foil disposed on the first layer of material loaded with electrically conductive particles.
According to a first embodiment, the battery in accordance with the invention has a capacity less than or equal to 1 mA h.
According to an alternative embodiment, the battery in accordance with the invention has a capacity greater than 1 mA h.
The appended figures, given by way of non-limiting examples, represent different aspects and embodiments of the invention.
One associates with this battery, by convention, the following geometric names.
ZZ the direction called frontal direction, namely perpendicular to the plane of the different stacked layers of the battery according to the invention
XX the direction called longitudinal direction, which is included in the plane of the stacked layers and which is parallel to the largest dimension of these layers forming the stack of the battery according to the invention, in top view, namely in the frontal direction
YY the direction called lateral or transverse direction, which is included in the plane of the stacked layers and which is parallel to the smallest dimension of these layers, in top view.
Also by convention, the two orientations associated with each of these three directions are given with reference to the plane of the foil on which
For the direction XX, one therefore associates the rightward orientation and the leftward orientation, for the direction YY, one associates the forward orientation and the backward orientation, and for the direction ZZ, one associates the upward orientation and the downward orientation, with reference to the plane of the foil on which
Also by convention, one defines a first longitudinal orientation XX′ directed from right to left and a second longitudinal orientation XX″, opposite to the first longitudinal orientation XX′, namely directed from left to right, with reference to the plane of the foil on which
In order to characterise the barrier properties of an encapsulation system, one refers, in the present description, to the WVTR coefficient (Water Vapor Transmission Rate) which characterises the water vapor permeance of an encapsulation system. The lower the WVTR coefficient, the more waterproof the encapsulation system. The water vapor permeance (WVTR) can be determined using a method which is the subject of the U.S. Pat. No. 7,624,621 and which is also described in the publication “Structural properties of ultraviolet cured polysilazane gas barrier layers on polymer substrates” by A. Morlier et al., published in the journal Thin Solid Films 550 (2014) 85-89.
The present invention aims at manufacturing of a battery as shown in
As illustrated in
As represented in
As represented in
The battery according to the invention is formed from a stack I comprising, in the longitudinal direction XX, x rows with x strictly greater than 1 as well as y line(s) with y greater than or equal to 1, so as to form a number (x*y) of batteries. The stack I is formed by an alternating succession of strata respectively cathode SC, SC1, SC2, . . . SCn and anode SA, SA1, SA2, . . . SAn strata, each cathode stratum SC, SC1, SC2, . . . SCn being intended to form a number (x*y) of cathode entities 140 while each anode stratum SA, SA1, SA2, . . . SAn is intended to form a number (x*y) of anode entities 110.
Each anode stratum SA, SA1, SA2, . . . SAn of the stack I according to the invention comprises, in the frontal direction ZZ of the stack I, parallel to the frontal direction ZZ of the final battery 1000, an anode current collector substrate 10, at least one anode layer 20, and possibly a layer of an electrolyte material 30 or a separator 31 impregnated with an electrolyte.
Each cathode stratum SC, SC1, SC2, . . . SCn of the stack I according to the invention comprises, in the frontal direction ZZ of the stack I, parallel to the frontal direction ZZ of the final battery 1000, a cathode current collector substrate 40, at least one cathode layer 50, and possibly a layer of an electrolyte material 30 or a separator 31 impregnated with an electrolyte.
Each stratum SA, SA1, SA2, . . . SAn, SC, SC1, SC2, . . . SCn comprises: a plurality of primary preforms 111′, 141′, respectively anode 111′ and cathode 141′ primary preforms, each of which is intended to form a respective primary body 111, 141, a plurality of secondary preforms 112′, 142′, respectively anode 112′ and cathode 142′ secondary preforms, each of which is intended to form a respective secondary body 112, 142.
The primary preform 111′, 141′ and the secondary preform 112′, 142′ being mutually separated by a zone called empty zone 80″, 70″, which is intended to form at least one of the free spaces 113, 143 of the battery 1000.
According to the first embodiment of the invention, the method in accordance with the invention comprises firstly a step in which a stack I of alternating strata SA, SA1, SA2, . . . SAn, SC, SC1, SC2, . . . SCn is made. In this first embodiment, each of these strata is a foil made in one piece. In the following, these different foils are called, as the case, “anode foils” or “cathode foils”. As will be seen in more detail, each anode foil is intended to form the anode of several batteries, and each cathode foil is intended to form the cathode of several batteries. In the example illustrated in
In an advantageous embodiment, each of these foils has perforations 7 at the four corners thereof so that when these perforations 7 are superimposed, all cathodes and all anodes of these foils are arranged according to the invention, as this will be explained in greater detail hereinafter (see
Each anode foil comprises an anode current collector substrate 10 coated with an active layer of an anode material 20, hereinafter anode layer 20. Each cathode foil comprises a cathode current collector substrate 40 coated with an active layer 20 of a cathode material 50, hereinafter referred to as cathode layer 50. Each of these active layers can be solid, and more particularly of dense or porous nature. Moreover, in order to avoid any electrical contact between two active layers of opposite polarities, an electrolyte layer 30 or a layer of separator 31 which is subsequently impregnated with an electrolyte is disposed on the active layer of at least one of these current collector substrates previously coated with the active layer, in contact with the opposite active layer. The electrolyte layer 30 or the separator layer 31, may be disposed on the anode layer 20 and/or on the cathode layer 50; the electrolyte layer 30 or the separator layer 31 is an integral part of the anode foil and/or the cathode foil comprising it.
Advantageously, the two faces of the anode 10, respectively cathode 40, current collector substrate are coated with an anode layer 20, respectively with a cathode layer 50, and optionally with an electrolyte layer 30 or a separator layer 31, disposed on the anode layer 20, respectively on the cathode layer 50. In this case, the anode 10, respectively cathode 40, current collector substrate serves as a current collector for two adjacent unit cells 100, 100′. The use of these substrates in the batteries allows increasing the production efficiency of rechargeable batteries with high energy density and high power density.
The mechanical structure of one of the anode foils is described hereinafter, given that the other anode foils have an identical structure. Moreover, as will be seen in what follows, the cathode foils have a structure similar to that of the anode foils.
As shown in
The slots 80 are distributed along lines L1 to Ly, disposed one below the other, as well as along rows R1 to Rx provided next to each other. By way of non-limiting examples, in the context of the manufacture of surface mounted component type microbatteries (hereinafter SMC), the used anode and cathode foils can be plates of 100 mm×100 mm. Typically, the number of lines of these foils is comprised between 10 and 500, while the number of rows is comprised between 10 and 500. Depending on the desired capacity of the battery, these dimensions may vary and the number of lines and rows by anode and cathode foils can be adapted accordingly. The dimensions of the used anode and cathode foils can, in other words, be modulated according to the needs. As shown in
The slots 70, 80 are through slots, namely that they open onto the opposite faces, respectively upper and lower faces of the foil, as will be seen in more detail hereinafter. These slots 70, 80 preferably have a quadrilateral shape, typically of rectangular type. In the illustrated example, these slots each have an I-shape, which makes them very easy to use. These slots 70, 80 can be made in a manner known per se, directly on the current collector substrate, before any deposition of anode or cathode materials by chemical etching, by electroforming, by laser cutting, by microperforation or by stamping.
These slots 70, 80 can also be made: on current collector substrates coated with an anode or cathode material layer, or on current collector substrates coated with an anode or cathode material layer, itself coated with an electrolyte layer or a separator layer, i.e. on anode or cathode foils.
When the slots 70, 80 are made on such coated substrates, the slots 70, 80 can be made in a manner known per se, for example by laser cutting (or laser ablation), by femtosecond laser cutting, by microperforation or by stamping.
As illustrated in
In top view and as illustrated in
One will now describe the slots 70, 80 as illustrated in
Each anode slot 80 has, preferably, a quadrilateral shape, typically of rectangular type. It bears noting: I80 the width of the entire anode slot 80, which is typically comprised between 0.25 mm and 10 mm; and L80 the length thereof which is typically comprised between 0.01 mm and 0.5 mm.
As shown in particular in
As seen above, the structures of the anode 80 and cathode 70 slots are similar. Moreover, in top view, the anode slots 80 are offset relative to the cathode slots 70, in the longitudinal direction XX. In this manner, in top view, the anode 80 and cathode 70 slots are not coincident and are distinct from each other.
The stack I comprises an alternating arrangement of at least one anode foil 2e having slots 80 and of at least one cathode foil 5e having slots 70. Thus, at least one unit cell 100 is obtained, comprising successively an anode current collector substrate 10, an anode layer 20, a layer of an electrolyte material 30 and/or a separator layer 31 subsequently impregnated with an electrolyte, a cathode layer 50, and a cathode current collector substrate 40.
This stack I is made such that in a top view: the cathode slots 70 made in all cathode foils 5e are coincident, i.e. are mutually superimposed, the anode slots 80 made in all anode foils 2e are coincident, i.e. are mutually superimposed, and the anode 80 and cathode 70 slots are not coincident and are distinct from each other.
In the case where the battery comprises a plurality of unit cells 100, 100′, 100″, the unit cells 100, 100′, 100″ are disposed one below the other, namely superimposed in a frontal direction ZZ to the main plane of the battery as represented in
It is assumed that the stack I, described above, is subjected to steps aimed at ensuring the overall mechanical stability thereof. These steps, of a type known per se, include in particular the heat and/or mechanical treatment of the various different foils 2e, 5e having slots 80, 70. As will be seen below, this stack thus consolidated allows the formation of individual batteries, whose number is equal to the product between the number of lines Y and the number of rows X.
To this end, with reference to
As shown in particular in
With reference again to
The anode foil 2e having small empty zones, i.e. slots comprises an anode current collector substrate 10 coated with an anode layer 20, itself optionally coated with an electrolyte layer 30 or a layer of separator 31 subsequently impregnated with an electrolyte. Each cathode foil 5e having small empty zones, ie slots comprises a cathode current collector substrate 40 coated with an active layer of a cathode material 50, itself optionally coated with an electrolyte layer 30 or a layer of separator 31 subsequently impregnated with an electrolyte. In order to avoid any electrical contact between two active layers of opposite polarity, i.e. between the anode layer 20 and the cathode layer 50, at least one electrolyte layer 30 and/or at least one layer of separator 31 impregnated or subsequently impregnated with an electrolyte is/are disposed. In
Advantageously, the anode current collector substrate 10 of a unit cell 100′ can be joined to the anode current collector substrate 10 of the adjacent unit cell 100″. Similarly, the cathode current collector substrates of two adjacent unit cells 100, 100′ can be joined to each other.
In an advantageous embodiment, the anode 10, respectively cathode 40, current collector substrate can serve as a current collector for two adjacent unit cells, as illustrated in particular in
As represented in
In
This feature is particularly advantageous, since it allows improving the quality of the cut relative to the prior art and avoiding the presence of a short-circuit at the longitudinal faces F6, F4 of the battery, avoiding the presence of leakage current, and facilitating electrical contact at the anode 1002 and cathode 1006 connection zones. With reference to
Advantageously, after making the stack of the anode foils having slots 2e and cathode foils having slots 5e, the stack I is consolidated by heat and/or mechanical treatment (this treatment can be a thermocompression treatment, comprising the simultaneous application of a pressure and a high temperature). The heat treatment of the stack allowing the assembly of the battery is advantageously carried out at a temperature comprised between 50° C. and 500° C., preferably at a temperature below 350° C. The mechanical compression of the stack of the anode foils having slots 2e and cathode foils having slots 5e to be assembled is carried out at a pressure comprised between 10 MPa and 100 MPa, preferably between 20 MPa and 50 MPa.
Making the consolidated stack of foils which constitute the battery has just been described. It is then possible, when the stack I comprises several lines also called hereinafter battery lines Ln, to make a first pair of cuts called accessory cuts DXn and DX′n allowing separating a given line Ln of batteries 1000 from at least one other line Ln−1, Ln+1 of batteries formed from the consolidated stack. Each cut, which is performed right through, namely which extends over the entire height of the stack, is carried out in a manner known per se, as indicated above.
When a separator is used as a host matrix of an electrolyte, the previously obtained consolidated stack or the line Ln of batteries 1000 can be impregnated when the initial stack I comprises several battery lines Ln and a first pair of cuts (DXn, DX′n) was made in order to separate the given line (Ln) of batteries (1000) from at least one other line (Ln−1, Ln+1) of batteries (1000) formed from the consolidated stack. The impregnation of the previously obtained consolidated stack or the line Ln of batteries 1000 can be carried out, with a lithium ion carrier phase such as liquid electrolytes or an ionic liquid containing lithium salts, such that the separator layer (31) is impregnated with an electrolyte.
In general, within the scope of the present invention, it is possible to impregnate the separator, but also the electrodes. The structure can also include a combination of impregnated solid and/or mesoporous electrodes and/or can include a solid electrolyte and/or an impregnated separator.
After making a consolidated stack I or a line Ln of batteries 1000, possibly impregnated with a lithium ion carrier phase, this stack or this line Ln of batteries 1000 is encapsulated by depositing an encapsulation system 95 to ensure the protection of the battery cell from the atmosphere, as represented in
The battery line Ln thus encapsulated has six faces, namely: two faces called front faces FF1, FF2 which are mutually opposite, in the example mutually parallel, generally parallel to the anode entities, generally parallel to the cathode entities, generally parallel to the anode current collector substrate(s) 10, to the anode layer(s) 20, to the layer(s) of an electrolyte material 30 or to the layer(s) of separator impregnated with an electrolyte 31, to the cathode layer(s) 50, and to the cathode current collector substrate(s) 40; two faces called lateral faces FF3, FF5 which are mutually opposite, in particular mutually parallel and parallel to the lateral faces F3, F5 of the battery 1000; and two faces called longitudinal faces FF4, FF6, which are mutually opposite, in particular mutually parallel and parallel to the longitudinal faces F4, F6 of the battery 1000.
The encapsulation system must advantageously be chemically stable, withstand high temperature and be impermeable to the atmosphere in order to perform its function as a barrier layer. The stack can be covered with an encapsulation system comprising: optionally a first dense and insulating cover layer, preferably selected from parylene, parylene type F, polyimide, epoxy resins, silicone, polyamide, sol-gel silica, organic silica and/or a mixture thereof, deposited on the outer periphery of the stack I of anode 2e and cathode 5e foils, and, preferably, also in the free spaces 113, 143 present between the primary 111, 141 and secondary 112, 142 bodies of each anode entity 110 and each cathode entity 140; optionally a second cover layer composed of an electrically insulating material, deposited by deposition of atomic layers on the outer periphery of the stack I of anode 2e and cathode 5e foils, and, preferably, also in the free spaces 113, 143 present between the primary 111, 141 and secondary 112, 142 bodies of each anode entity 110 and each cathode entity 140, or on the first cover layer; and particularly advantageously, at least one third waterproof cover layer, preferably having a WVTR coefficient of less than 10−5 g/m2·d. The third cover layer is composed of a ceramic material and/or a low melting point glass, preferably a glass whose melting point is less than 600° C., deposited on the outer periphery of the stack I of anode 2e and cathode 5e foils, and, preferably, also in the free spaces 113, 143 present between the primary 111, 141 and secondary 112, 142 bodies of each anode entity 110 and each cathode entity 140 or on the first cover layer. Given that a sequence of at least one second cover layer and at least one third cover layer can be repeated z times with z 1 and deposited on the outer periphery of at least the third cover layer, and that the last layer of the encapsulation system is a waterproof cover layer, preferably having a WVTR coefficient of less than 10−5 g/m2·d which is composed of a ceramic material and/or a low melting point glass. This sequence can be repeated z times with z 1. It has a barrier effect, which is all the more significant the higher the value of z. A rigid and waterproof encapsulation is thus obtained, which prevents, in particular, the passage of water vapor at the interface between the encapsulation system and the contact members (see interface AA represented in
Typically, the first cover layer, which is optional, is selected from the group formed by: silicones (deposited for example by impregnation or by plasma-enhanced chemical vapor deposition from hexamethyldisiloxane (HMDSO)), resins epoxy, polyimide, polyamide, poly-para-xylylene (also called poly (p-xylylene, but better known as parylene), and/or a mixture thereof. When a first cover layer is deposited, it allows protecting the sensitive elements of the battery from its environment. The thickness of the first cover layer is, preferably, comprised between 0.5 μm and 3 μm.
This first cover layer is useful especially when the electrolyte and electrode layers of the battery have porosities: it acts as a planarization layer, which also has a barrier effect. By way of example, this first layer is capable of lining all accessible surfaces of the stack or the line Ln of batteries 1000, in particular the outer periphery of the stack or the line line Ln of batteries 1000, to close the access of the through-microporosities present on the surface of the stack I or of the line Ln of batteries 1000.
In the first cover layer, different variants of parylene can be used. It can 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 is a dielectric, transparent, semi-crystalline material which has a high thermodynamic stability, excellent resistance to solvents as well as very low permeability. Parylene also has barrier properties. Within the scope of the present invention, parylene type F is preferred.
This first cover layer is advantageously obtained from the condensation of gaseous monomers deposited by Chemical Vapor Deposition (CVD) on the surfaces of the stack of the battery, which allows having a conformal, thin and uniform covering of all accessible surfaces of the stack. This first cover layer is advantageously rigid; it cannot be considered as a soft surface.
The second cover layer, which is also optional, is composed of an electrically insulating material, preferably inorganic. It is deposited by Atomic Layer Deposition (ALD), by PECVD, by HDPCVD (High Density Plasma Chemical Vapor Deposition) or by ICPCVD (Inductively Coupled Plasma Chemical Vapor Deposition), so as to obtain a conformal covering of all accessible surfaces of the stack which is previously covered with the first cover layer. The layers deposited by ALD are very fragile mechanically and require a rigid bearing 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. Moreover, 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 an inhomogeneous growth, which may cause a loss of integrity of this protective layer. For this reason, it is preferable for this second optional layer, if it is present, to bear on the first optional layer, which ensures a chemically homogeneous growth substrate.
The ALD deposition techniques are particularly well adapted for covering surfaces having a high roughness in a completely sealed and compliant manner. They allow making conformal layers, free of defects, such as holes (layers called “pinhole free” layers, i.e. free of holes) and represent very good barriers. Their WVTR coefficient is extremely low. The thickness of this second layer is advantageously selected depending on the desired gas tightness level, i.e. the desired WVTR coefficient and depends on the used deposition technique, in particular among ALD, PECVD, HDPCVD and ICPCVD.
The second cover layer can be made of ceramic material, of vitreous material or of glass-ceramic material, for example in the form of oxide, of Al2O3, Ta2O5, nitride, phosphates, oxynitride, or siloxane type. This second cover layer preferably has a thickness comprised between 10 nm and 5 μm, preferably between 10 nm and 50 nm. The second cover layer deposited by ALD, by PECVD, by HDPCVD or by ICPCVD on the first cover layer allows, on the one hand, ensuring the waterproofness the structure, i.e. preventing the migration of water inside the object and, on the other hand, protecting the first cover layer, preferably of parylene type F, from the atmosphere, in particular air and humidity, thermal exposures in order to avoid its degradation. This second cover layer thus improves the service life of the encapsulated battery. The second cover layer can also be deposited directly on the stack of anode and cathode foils, that is to say in a case where the first cover layer has not been deposited.
The third cover layer must be waterproof and preferably has a WVTR coefficient of less than 10−5 g/m2·d. This third cover layer being composed of a ceramic material and/or a low melting point glass, preferably a glass whose melting point is less than 600° C., deposited on the outer periphery of the stack of anode and cathode foils or the first cover layer. The ceramic and/or glass material used in this third layer is advantageously selected from: a low melting point glass (typically <600° C.), preferably SiO2—B2O3; Bi2O3—B2O3, ZnO—Bi2O3—B2O3, TeO2—V2O5, PbO—SiO2, and oxides, nitrides, oxynitrides, SixNy, SiO2, SiON, amorphous silicon or SiC. These glasses can be deposited by molding or by dip-coating. The ceramic materials are advantageously deposited by PECVD or preferably by HDPCVD or by ICP CVD at low temperature; these methods allow depositing a layer having good sealing properties.
As represented in particular in
Advantageously and as represented in
According to the invention, and in a particularly advantageous manner, the second pair of cuts DYn, DY′n as represented in
Thus, one covers at least the anode connection zone 1002, preferably at least the first longitudinal face F6 comprising at least the anode connection zone 1002, and more preferably the first longitudinal face F6 comprising at least the anode connection zone 1002 as well as the ends 97′a of the faces F1, F2, F3, F5 adjacent to this first longitudinal face F6, by an anode contact member 97′, capable of ensuring the electrical contact between the stack I and an outer conductive element. Moreover, one covers at least the cathode connection zone 1006, preferably at least the second longitudinal face F4 comprising at least the cathode connection zone 1006, and more preferably the second longitudinal face F4 comprising at least the cathode connection zone 1006 as well as the ends 97″a of the faces F1, F2, F3, F5 adjacent to this second longitudinal face F4, by a cathode contact member 97″, capable of ensuring the electrical contact between the stack I and an outer conductive element (see
Preferably, in the vicinity of the cathode 1006 and anode 1002 connection zones as previously indicated, the contact members 97, 97′, 97″ consist of, a stack of electrical connection layers comprising successively a first electrical connection layer comprising a material loaded with electrically conductive particles, preferably a polymeric resin and/or a material obtained by a sol-gel method, loaded with electrically conductive particles and even more preferably a polymeric resin loaded with graphite, and a second layer consisting of a metal foil disposed on the first electrical connection layer.
The first electrical connection layer allows fastening the second subsequent electrical connection layer while providing “flexibility” to the connectivity without breaking the electrical contact when the electrical circuit is subjected to thermal and/or vibratory stresses.
The second electrical connection layer is advantageously a metal foil. This second electrical connection layer is used to permanently protect the batteries from humidity. In general, for a given thickness of material, metals allow making very waterproof films, more waterproof than those based on ceramics and even more waterproof than those based on polymers which are generally not very hermetic to the passage of water molecules. It allows increasing the calendar service life of the battery by reducing the WVTR coefficient at the contact members.
Advantageously, a third electrical connection layer comprising a conductive ink can be deposited on the second electrical connection layer; it is used to reduce the WVTR coefficient, which increases the service life of the battery.
The contact members 97, 97′, 97″ allow resuming the alternately positive and negative electrical connections on each of the ends. These contact members 97, 97′, 97″ allow making the electrical connections in parallel between the different battery elements. For this, only the cathode connections are available on one end, and the anode connections are available on another end.
The application WO 2016/001584 describes stacks of several unit cells, consisting of anode and cathode foils stacked alternately and laterally offset (see
According to the present invention, this risk is eliminated with the use of foils according to the invention carrying slots where, in top view: the cathode slots 70 (which will form the free spaces 143, 70 of any material of electrolyte, separator, current collector substrate and electrode, in particular of cathode) made in all cathode foils 5e are coincident, i.e. are mutually superimposed, the anode slots 80 (which will form the free spaces 113, 80 of any material of electrolyte, separator, current collector substrate and electrode, in particular of anode) made in all anode foils 2e are coincident, i.e. are mutually superimposed, and the anode 80 and cathode 70 slots are not the coincident and are distinct from each other.
In this manner, each cathode entity 140 of the battery 1000 comprises a primary body 141 separated from a secondary body 142 by a free space 143, 70 of any material of electrolyte, separator, current collector substrate and electrode, in particular of cathode. Similarly, each anode entity 110 of the battery 1000 comprises a primary body 111 separated from a secondary body 112 by a free space 113, 80 of any material of electrolyte, separator, current collector substrate and electrode, in particular of anode (see
The heat-pressed mechanical structure of the stack is extremely rigid in the vicinity of the cuts along the cutting lines DY′n and DYn, due to the alternating superimposition of cathode and anode foils. The use of such a rigid structure, with the use of foils carrying slots, allows reducing the number of defects during the cuts, increasing the cutting speed, improving the production efficiency of the batteries while minimizing the material falls.
According to the invention, the cuts DY′n and DYn are performed through anode foils having slots 2e and cathode foils having slots 5e of comparable density inducing a clean cut of better quality. In addition, the presence of a free space of any material of electrode, electrolyte and/or current collector substrate prevents any risk of short-circuit.
As represented in
The anode connection zones 1002 and the cathode connection zones 1006 are preferably laterally opposite as illustrated in
The batteries according to the invention can be made according to different variants.
In this manner, the slot 70, 80 positioned in line Ln is coincident with at least one of the adjacent slots positioned in line Ln−1 and/or Ln+1. In this case and as illustrated in
To this end, with reference to
In
This second embodiment therefore differs, in other words, from the first embodiment essentially in that the different strips, respectively anode and cathode strips, are independent of each other. In this manner, each respective anode strip A1, A2, A3, A4 and cathode strip C1, C2, C3, C4 is not connected to a solid peripheral frame so as to form an anode, respectively cathode, foil as previously indicated.
According to the second embodiment of the invention, for a given row Rx, the anode strip A1, A2, A3, A4 is common to all lines L1 to Ly, disposed one below the other, and the cathode strip C1, C2, C3, C4 is common to all lines L1 to Ly, arranged one below the other.
According to the second embodiment of the invention and as illustrated in
It is assumed that the stack of anode and cathode strips, 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 treatment and/or the mechanical compression of the stack of the different strips, as has been previously described. As previously indicated, this stack allows the formation of individual batteries, whose number is equal to the product between the number of lines Y and the number of rows X.
To this end, with reference to
The subsequent steps of impregnating, encapsulating, cutting along the cutting lines DYn and DY′n, as illustrated in
According to the variant of
The method according to the invention is particularly adapted for the manufacture of fully solid batteries, i.e. batteries whose electrodes and electrolyte are solid and do not comprise a liquid phase, even impregnated in the solid phase. The method according to the invention is particularly adapted for the manufacture of batteries considered to be quasi-solid comprising at least one separator 31 impregnated with an electrolyte. The separator is preferably a porous inorganic layer having: a porosity, preferably a mesoporous porosity, greater than 30%, preferably comprised between 35% and 50%, and even more preferably between 40% and 50%, and pores of average diameter D50 less than 50 nm.
The thickness of the separator is advantageously less than 20 μm, and preferably comprised between 5 μm and 10 μm, so as to reduce the final thickness of the battery without reducing its properties. The pores of the separator are impregnated with an electrolyte, preferably with a lithium ion carrier phase such as liquid electrolytes or an ionic liquid containing lithium salts. The liquid which is “nano-confined” or “nano-trapped” in the porosities, and in particular in the mesoporosities, can no longer come out. It is linked by a phenomenon called herein “absorption in the mesoporous structure” (which does not seem to have been described in the literature in the context of lithium-ion batteries) and it can no longer come out even when the cell is put under vacuum. The battery is then considered as quasi-solid.
The battery according to the invention can be designed and dimensioned so as to have: a capacity less than or equal to about 1 mA h (commonly called “microbattery”), or a capacity greater than about 1 mA h.
Typically, the microbatteries are designed to be compatible with microelectronics manufacturing methods.
The batteries of each of these power ranges can be made: either with “all solid” type layers, i.e. devoid of impregnated liquid or pasty phases (the liquid or pasty phases can be a conductive medium of lithium ions, capable of acting as an electrolyte), either with mesoporous “all solid” type layers, impregnated with a liquid or pasty phase, typically a lithium ion conductive medium, which spontaneously enters inside the layer and which no longer comes out from this layer, such that this layer can be considered as quasi-solid, or with impregnated porous layers (i.e. layers having a network of open pores which can be impregnated with a liquid or pasty phase, and which gives these layers wet properties).
The following references are used in these figures and in the following description:
| Number | Date | Country | Kind |
|---|---|---|---|
| 2005140 | May 2020 | FR | national |
The present application is a National Stage Application of PCT International Application No. PCT/IB2021/054292 (filed on May 19, 2021), under 35 U.S.C. § 371, which claims priority to French Patent Application No. FR 2005140 (filed on May 20, 2020), which are each hereby incorporated by reference in their complete respective entireties.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2021/054292 | 5/19/2021 | WO |
