Systems and methods for improving security features in electrochemical cells

Abstract

Embodiments described herein generally relate to systems and methods for improving safety features in electrochemical cells. In particular, the systems and methods as described herein may address safety issues associated with gas generation in electrochemical cells. An electrochemical cell includes a housing including a first portion having a first sealing region and a second portion having a second sealing region.

Description

[0001] This application is a divisional application of the invention patent application entitled “System and method for improving safety features in electrochemical batteries”, with an international application date of February 1, 2018, an international application number of PCT / US2018 / 016406, and a national application number of 201880018682.5.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to and the benefit of U.S. Provisional Patent Application Serial No. 62 / 453,197, filed on February 1, 2017, entitled “Systems and Methods for Improving Safety Features in Electrochemical Cells,” the entire disclosure of which is incorporated herein by reference. Background Art

[0004] Although lithium-ion batteries (or electrochemical cells) have become popular, consumer safety of these devices has also become critical. In normal operation, electrochemical reactions occur inside lithium-ion batteries to generate electricity. These reactions also produce byproducts. In particular, the gaseous products produced during the formation, operation and storage of lithium-ion batteries pose huge technical challenges. The gases released during formation require additional degassing processes, thereby increasing production costs. Gas escape during the cycle of the formed battery, especially under overcharge conditions, can lead to internal pressure accumulation, performance degradation and potential safety failures. Gas generation during storage, especially at high temperatures, can lead to a shortened shelf life of the product. The dilemma is also challenging for batteries packaged in soft foil laminated plastics due to potential harmful dimensional changes and packaging damage. Summary of the invention

[0005] Embodiments described herein generally relate to systems and methods for improving safety features in electrochemical cells. In particular, the systems and methods described herein can address safety issues related to gas generation in electrochemical cells.

[0006] In certain embodiments, a device includes a housing for an electrochemical cell, the housing including a first portion having a first sealing area and a second portion having a second sealing area. The first portion of the housing can be configured to partially define a first cavity, the first cavity being configured to receive a cathode, and the second portion of the housing can be configured to partially define a second cavity, the second cavity being configured to receive an anode. A separator is arranged between the cathode and the anode, and the separator is coupled to a portion of the first sealing area and a portion of the second sealing area. A fluid flow path is arranged between a portion of the first sealing portion and the second sealing portion, and the fluid flow path is configured to allow gas generated during operation of the electrochemical cell to flow from at least one of the first cavity and the second cavity to an area outside the housing.

[0007] In some embodiments, the device may include a third cavity fluidly coupled to at least one of the first cavity and the second cavity, the third cavity being configured to receive the gas generated during operation of the electrochemical cell. In some embodiments, the third cavity is external to the housing. In some embodiments, the third cavity is fluidly coupled to at least one of the first cavity and the second cavity in a first configuration and fluidly isolated from the first cavity and the second cavity in a second configuration. In some embodiments, the third cavity is configured to be removable from the housing in the second configuration. In some embodiments, the third cavity has a volume between about 5% and about 50% of the volume of the housing.

[0008] In some embodiments, the device is configured so that the separator extends through the first sealing area and the second sealing area to form the fluid flow path from at least one of the first cavity and the second cavity to the area outside the housing. In some embodiments, the portion of the separator forming the fluid flow path is porous. In some embodiments, the fluid flow path is configured to fluidically communicate the gas without interfering with the normal operation of the electrochemical cell. In some embodiments, the porous portion of the separator has a porosity of about 1% to about 90%. In some embodiments, the porous portion of the separator has pores with a size of about 1 μm to about 200 μm.

[0009] In certain embodiments, the device includes a housing for an electrochemical cell, the housing including a first portion having a first sealing area and a second portion having a second sealing area. The first portion of the housing is configured to partially define a first cavity, the first cavity is configured to receive a cathode, and the second portion of the housing is configured to partially define a second cavity, the second cavity is configured to receive an anode. A separator is disposed between the cathode and the anode, and the separator is coupled to a portion of the first sealing area and a portion of the second sealing area.

[0010] In certain embodiments, the device may include a safety mechanism that is operably coupled to the electrochemical cell and is configured to terminate the electrical operation of the electrochemical cell when the gas pressure in at least one of the first cavity and the second cavity exceeds a threshold value. In certain embodiments, the safety mechanism may include a thinned portion of the housing that is configured to open when the gas pressure in at least one of the first cavity and the second cavity exceeds the threshold value. In certain embodiments, the threshold gas pressure is between about 5 psi and about 2000 psi. In certain embodiments, the threshold gas pressure is greater than about 40% of the predicted gas pressure that will cause the electrochemical cell to fail suddenly. In certain embodiments, the thinned portion has a thickness ratio of less than about 0.5 compared to other portions of the housing.

[0011] In certain embodiments, the safety mechanism may include a circuit interruption device configured to disconnect the electrochemical cell from the circuit when the gas pressure in at least one of the first cavity and the second cavity exceeds the threshold. In certain embodiments, the device also includes a cathode tab electrically coupled to the cathode and an anode tab electrically coupled to the anode. In certain embodiments, the circuit interruption device may include a narrow portion formed in at least one of the cathode tab and the anode tab, the narrow portion configured to rupture when the gas pressure in at least one of the first cavity and the second cavity exceeds the threshold.

[0012] In certain embodiments, the device is configured such that the cathode is electrically coupled to a cathode current collector and the safety mechanism is configured to physically separate the cathode from at least one of the cathode current collector and the separator when the gas pressure within at least one of the first cavity and the second cavity exceeds the threshold, thereby terminating electrical operation of the electrochemical cell.

[0013] In certain embodiments, the apparatus is configured such that the anode is electrically coupled to an anode current collector and the safety mechanism is configured to physically separate the anode from at least one of the anode current collector and the separator when the gas pressure within at least one of the first cavity and the second cavity exceeds the threshold, thereby terminating electrical operation of the electrochemical cell.

[0014] In certain embodiments, the device includes a housing for an electrochemical cell, the housing including a first portion having a first sealing area and a second portion having a second sealing area. The first portion of the housing is configured to partially define a first cavity, the first cavity is configured to receive a cathode, and the second portion of the housing is configured to partially define a second cavity, the second cavity is configured to receive an anode. A separator is arranged between the cathode and the anode, and the separator is coupled to the first sealing area and the second sealing area, and a portion of the separator extends through the first sealing area and the second sealing area to create a fluid flow path from at least one of the first cavity and the second cavity to an area outside the housing.

[0015] In some embodiments, the portion of the separator that forms the fluid flow path is porous. In some embodiments, the porous portion of the separator has a porosity of about 1% to about 90%. In some embodiments, the porous portion of the separator has pores with a size of about 1 μm to about 200 μm. In some embodiments, the porous portion of the separator is configured to allow the gas generated during the operation of the electrochemical cell to flow from at least one of the first cavity and the second cavity to the area outside the housing. In some embodiments, the fluid flow path is configured to fluidly communicate the gas without interfering with the normal operation of the electrochemical cell. In some embodiments, the gas is formed in at least one of the three situations during the formation of the electrochemical cell, during the normal operation of the electrochemical cell, and when the gas pressure in the housing exceeds a threshold. In some embodiments, the threshold gas pressure is between about 5 psi and about 2000 psi. In some embodiments, the threshold gas pressure is greater than about 40% of the predicted gas pressure that will cause the electrochemical cell to fail suddenly. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figures 1A to 1C A schematic diagram of an electrochemical cell including a vent for releasing gases generated during operation of the cell is shown according to an embodiment.

[0017] FIG. 2A to FIG. 2CA schematic diagram of an electrochemical cell using a porous separator to release gases generated during operation of the cell is shown according to an embodiment.

[0018] Figure 3 A schematic diagram of an electrochemical cell including an auxiliary bag to absorb gas and regulate gas pressure within the cell is shown according to an embodiment.

[0019] FIG. 4A to FIG. 4C A schematic diagram of an electrochemical cell including a single-pouch circuit interruption device to protect the cell from over-pressure due to gas generation is shown according to an embodiment.

[0020] Figure 5 A schematic diagram of an electrochemical cell including a needle within the battery housing to protect the battery from overpressure is shown according to an embodiment.

[0021] FIG. 6A to FIG. 6C A schematic diagram illustrating a safety mechanism employing layering of electrodes according to certain embodiments. DETAILED DESCRIPTION

[0022] Embodiments described herein generally relate to systems and methods for improving safety features in electrochemical cells. In particular, the systems and methods described herein can improve safety with respect to gas generation in electrochemical cells.

[0023] Gas generation due to electrolyte decomposition is often one of the major issues for high-performance rechargeable batteries, especially lithium-ion (“Li-ion”) based batteries. For example, continuous gassing due to oxidation and reduction of electrolyte solvents is a common problem in high-voltage LiN1 0.5 Mn 1.5 In addition, metal dissolution in the electrolyte and decomposition products caused by high potentials can have an adverse effect on gas production, especially in the first charging cycle (i.e., during the formation of the graphite solid-electrolyte interface layer).

[0024] Among various designs of lithium-ion batteries, pouch cells are widely used because they are flexible and lightweight and can achieve high packaging efficiency (e.g., about 90% to 95%). In a typical pouch cell, conductive foil tabs are welded to the electrodes and sealed to the pouch to bring the positive and negative terminals of the pouch to the outside of the pouch.

[0025] In pouch cells, gas generation can cause swelling, and the pressure from the swelling can rupture the battery cover open and in some cases disconnect the display or electronic circuitry. Conventionally, manufacturers add excess film to create an "air pocket" on the outside of the pouch cell to contain the gas during the first charge. The air pocket can then be cut off and the package released as part of the finishing process. However, this approach does not address the problem of gas accumulation during subsequent charges, especially after the battery is delivered to the customer.

[0026] In certain embodiments, a device includes a housing for an electrochemical cell, the housing including a first portion having a first sealing area and a second portion having a second sealing area. The first portion of the housing can be configured to partially define a first cavity, the first cavity being configured to receive a cathode, and the second portion of the housing can be configured to partially define a second cavity, the second cavity being configured to receive an anode. A separator is arranged between the cathode and the anode, and the separator is coupled to a portion of the first sealing area and a portion of the second sealing area. A fluid flow path is arranged between a portion of the first sealing portion and the second sealing portion, and the fluid flow path is configured to allow gas generated during operation of the electrochemical cell to flow from at least one of the first cavity and the second cavity to an area outside the housing.

[0027] In some embodiments, the device may include a third cavity fluidly coupled to at least one of the first cavity and the second cavity, the third cavity being configured to receive the gas generated during operation of the electrochemical cell. In some embodiments, the third cavity is external to the housing. In some embodiments, the third cavity is fluidly coupled to at least one of the first cavity and the second cavity in a first configuration and fluidly isolated from the first cavity and the second cavity in a second configuration. In some embodiments, the third cavity is configured to be removable from the housing in the second configuration. In some embodiments, the third cavity has a volume between about 5% and about 50% of the volume of the housing.

[0028] In some embodiments, the device is configured so that the separator extends through the first sealing area and the second sealing area to form the fluid flow path from at least one of the first cavity and the second cavity to the area outside the housing. In some embodiments, the portion of the separator forming the fluid flow path is porous. In some embodiments, the fluid flow path is configured to fluidically communicate the gas without interfering with the normal operation of the electrochemical cell. In some embodiments, the porous portion of the separator has a porosity of about 1% to about 90%. In some embodiments, the porous portion of the separator has pores with a size of about 1 μm to about 200 μm.

[0029] In certain embodiments, the device includes a housing for an electrochemical cell, the housing including a first portion having a first sealing area and a second portion having a second sealing area. The first portion of the housing is configured to partially define a first cavity, the first cavity is configured to receive a cathode, and the second portion of the housing is configured to partially define a second cavity, the second cavity is configured to receive an anode. A separator is disposed between the cathode and the anode, and the separator is coupled to a portion of the first sealing area and a portion of the second sealing area.

[0030] In certain embodiments, the device may include a safety mechanism that is operably coupled to the electrochemical cell and is configured to terminate the electrical operation of the electrochemical cell when the gas pressure in at least one of the first cavity and the second cavity exceeds a threshold value. In certain embodiments, the safety mechanism may include a thinned portion of the housing that is configured to open when the gas pressure in at least one of the first cavity and the second cavity exceeds the threshold value. In certain embodiments, the threshold gas pressure is between about 5 psi and about 2000 psi. In certain embodiments, the threshold gas pressure is greater than about 40% of the predicted gas pressure that will cause the electrochemical cell to fail suddenly. In certain embodiments, the thinned portion has a thickness ratio of less than about 0.5 compared to other portions of the housing.

[0031] In certain embodiments, the safety mechanism may include a circuit interruption device configured to disconnect the electrochemical cell from the circuit when the gas pressure within at least one of the first cavity and the second cavity exceeds the threshold. In certain embodiments, the device also includes a cathode tab electrically coupled to the cathode and an anode tab electrically coupled to the anode. In certain embodiments, the circuit interruption device may include a narrow portion formed in at least one of the cathode tab and the anode tab, the narrow portion configured to rupture when the gas pressure within at least one of the first cavity and the second cavity exceeds the threshold.

[0032] In certain embodiments, the device is configured such that the cathode is electrically coupled to a cathode current collector and the safety mechanism is configured to physically separate the cathode from at least one of the cathode current collector and the separator when the gas pressure within at least one of the first cavity and the second cavity exceeds the threshold, thereby terminating electrical operation of the electrochemical cell.

[0033] In certain embodiments, the apparatus is configured such that the anode is electrically coupled to an anode current collector and the safety mechanism is configured to physically separate the anode from at least one of the anode current collector and the separator when the gas pressure within at least one of the first cavity and the second cavity exceeds the threshold, thereby terminating electrical operation of the electrochemical cell.

[0034] In certain embodiments, the device includes a housing for an electrochemical cell, the housing including a first portion having a first sealing area and a second portion having a second sealing area. The first portion of the housing is configured to partially define a first cavity, the first cavity is configured to receive a cathode, and the second portion of the housing is configured to partially define a second cavity, the second cavity is configured to receive an anode. A separator is arranged between the cathode and the anode, and the separator is coupled to the first sealing area and the second sealing area, and a portion of the separator extends through the first sealing area and the second sealing area to create a fluid flow path from at least one of the first cavity and the second cavity to an area outside the housing.

[0035] In some embodiments, the portion of the separator that forms the fluid flow path is porous. In some embodiments, the porous portion of the separator has a porosity of about 1% to about 90%. In some embodiments, the porous portion of the separator has pores with a size of about 1 μm to about 200 μm. In some embodiments, the porous portion of the separator is configured to allow the gas generated during the operation of the electrochemical cell to flow from at least one of the first cavity and the second cavity to the area outside the housing. In some embodiments, the fluid flow path is configured to fluidly communicate the gas without interfering with the normal operation of the electrochemical cell. In some embodiments, the gas is formed in at least one of the three situations during the formation of the electrochemical cell, during the normal operation of the electrochemical cell, and when the gas pressure in the housing exceeds a threshold. In some embodiments, the threshold gas pressure is between about 5 psi and about 2000 psi. In some embodiments, the threshold gas pressure is greater than about 40% of the predicted gas pressure that will cause the electrochemical cell to fail suddenly.

[0036] In certain embodiments, an electrochemical cell structure is designed to remove excess gas in the battery formation stage. In certain embodiments, an electrochemical cell structure is placed with strategically placed vents, the vents being designed to relieve the increased pressure caused by the gas generated during the normal operating conditions of the electrochemical cell. In certain embodiments, an electrochemical cell structure is strategically sealed with an engineered separator within a laminated electrode, the laminated electrode being designed to relieve the increased pressure caused by the gas generated during the normal operating conditions of the electrochemical cell. In certain embodiments, a safety mechanism is used to delaminate the electrodes to handle electrochemical cells that exceed a predetermined pressure threshold. In certain embodiments, a safety mechanism is used to terminate the electrical connection at the connector tab including an engineered fuse for handling electrochemical cells that exceed a predetermined pressure threshold. In certain embodiments, a safety mechanism is used to prevent sudden failures in electrochemical cells by using strategically placed pins in a can battery or a battery rack including a pouch battery.

[0037] As used herein, the terms "about" and "approximately" generally mean plus or minus 10% of the stated value, for example, about 250 μm would include 225 μm to 275 μm, and about 1000 μm would include 900 μm to about 1100 μm.

[0038] Figures 1A to 1CA schematic diagram of an electrochemical cell 100 is shown that includes a gas vent (also referred to simply as a vent) to address gas generation and potential high pressures in the cell. This method can be used at various stages of its production and service life.

[0039] The electrochemical cell 100 includes a cathode 110 (also referred to as cathode material) disposed on a cathode current collector 112, an anode 120 (also referred to as anode material) disposed on an anode current collector 122, and a separator 130 disposed therebetween. The components of the cathode 110, the cathode current collector 112, the anode 120, the anode current collector 122, and the separator 130 may be substantially contained in a bag 140, which is sealed along a sealing perimeter 142. The cathode tab 115 may be electrically connected to the cathode current collector 112 and extend beyond the bag 140 for connection to an external circuit. Similarly, the anode tab 125 is electrically connected to the anode current collector 115 and extends beyond the bag 140 for connection to an external circuit. In certain embodiments, the cathode tab 115 may be a portion of the cathode current collector 112 extending from the sealing perimeter 142, and the anode tab 125 may be a portion of the anode current collector 122 extending from the sealing perimeter 142. In other words, the cathode tab 115 and the anode tab 125 can be formed integrally with their respective current collectors. The bag 140 can separate the electrochemical cell 100 from the adjacent one or more cells in the battery module or battery pack, thereby reducing the risk of defect propagation and fire. The electrochemical cell 100 also includes a vent 145 located on the cathode side of the bag 140 to release gases generated during testing and / or operation of the electrochemical cell 100, thereby regulating the pressure within the bag 140.

[0040] In certain embodiments, the cathode material 110 may include, for example, nickel cobalt aluminum (NCA), core shell gradient (CSG), spinel-based lithium ion (LMO), lithium iron phosphate (LFP), cobalt-based lithium ion (LCO), and nickel cobalt manganese (NCM).

[0041] The anode material 120 may be selected from a variety of materials. In some embodiments, the anode material 120 includes a carbon-based material, including but not limited to hard carbon, carbon nanotubes, carbon nanofibers, porous carbon, and graphene. In some embodiments, the anode material 120 includes a titanium-based oxide, including but not limited to spinel Li4Ti5O 12(LTO) and titanium dioxide (TiO2, titanium dioxide). In some embodiments, the anode material 120 includes alloys or non-alloy materials, including but not limited to silicon, silicon monoxide (SiO), germanium and tin oxide (SnO2). In some embodiments, the anode material 120 includes transition metal compounds (e.g., oxides, phosphides, sulfides and nitrides). The general formula of the transition compound can be written as M x N y , wherein M may be selected from iron (Fe), cobalt (Co), copper (Cu), manganese (Mn) and nickel (Ni), and N may be selected from oxygen (O), phosphorus (P), sulfur (S) and nitrogen (N).

[0042] In some embodiments, the anode material 120 includes an intermetallic compound. The intermetallic compound can be based on the expression MM', where M is a metal element and M' is a different metal element. The intermetallic compound can also include more than two metal elements. The M atoms of the intermetallic compound can be, for example, Cu, Li, and Mn, and the M' element of the intermetallic compound can be, for example, Sb. Exemplary intermetallic compounds include Cu2Sb, Li2CuSb, and Li3Sb, among others. In one example, the intermetallic compound in the anode material can have a completely disordered structure in which the M or M' atoms are arranged in a random manner. In another example, the intermetallic compound in the anode material has a partially disordered structure in which the M or M' atoms in the lattice are arranged in a non-random manner.

[0043] In some embodiments, the anode material 120 may be porous, thereby increasing the surface area and increasing the rate of lithium insertion reaction in the resulting electrode. In one example, the anode material 120 includes porous Mn2O3, which can be prepared by, for example, thermal decomposition of MnCO3 microspheres. In another example, the anode material 120 includes porous carbon fibers, which are prepared by, for example, electrospinning a blended solution of polyacrylonitrile and poly(l-lactide) and then carbonizing. In some embodiments, the porosity of the anode material 120 can be achieved or increased by using a porous current collector. For example, the anode material 120 may include Cu2Sb, which is uniformly deposited on a porous foam structure to have a certain degree of porosity.

[0044] In some embodiments, at least one of the anode material 120 or the cathode material 110 may include a semi-solid or condensed ion storage liquid reactant. The term "semi-solid" means that the material is a mixture of a liquid phase and a solid phase, for example, a semi-solid, a particle suspension, a colloidal suspension, an emulsion, a gel or a micelle. "Condensed ion storage liquid" or "condensed liquid" means that the liquid is not just a solvent as in the case of an aqueous flow cell cathode electrolyte or an anolyte, but that the liquid itself is redox active. This liquid form can also be diluted or mixed with another non-redox active liquid as a diluent or solvent, including mixing with such a diluent to form a low melting point liquid phase, an emulsion or a micelle containing an ion storage liquid. In some embodiments, a semi-solid electrode composition (also referred to herein as a "semi-solid suspension" and / or "slurry") may include a suspension of electrochemically active agents (anode particles and / or cathode particles) and optional electronically conductive particles. The cathode particles and the conductive particles are co-suspended in an electrolyte to produce a cathode semi-solid. The anode particles and the conductive particles are co-suspended in an electrolyte to produce an anode semi-solid. The semisolid can flow due to applied pressure, gravity, or other implemented fields that exert forces on the semisolid, and optionally with the aid of mechanical vibrations. An example of a battery utilizing a semisolid suspension is described in U.S. Patent No. 9,362,583, entitled "SEMI-SOLID ELECTRODES HAVING HIGH RATE CAPABILITY," the entire disclosure of which is incorporated herein by reference.

[0045] In some embodiments, one or both of the current collectors 112 and 122 may include a conductive substrate. In one example, the conductive substrate includes a metal material, such as aluminum, copper, lithium, nickel, stainless steel, tantalum, titanium, tungsten, vanadium, or a combination or alloy thereof. In another example, the conductive substrate includes a non-metallic material, such as carbon, carbon nanotubes, or a metal oxide (e.g., TiN, TiB2, MoSi2, n-BaTiO3, Ti2O3, ReO3, RuO2, IrO2, etc.).

[0046] In certain embodiments, one or both of the current collectors 112 and 122 may include a base substrate having one or more surface coatings to improve the mechanical, thermal, chemical or electrical properties of the current collector. In one example, one or more coatings on the current collector may be configured to reduce corrosion and change adhesion properties (e.g., hydrophilic or hydrophobic coatings, respectively). In another example, one or more coatings on the current collector may include a material with high electrical conductivity to improve the total charge transfer of the base substrate. In yet another example, the coating may include a material with high thermal conductivity to promote heat dissipation of the base substrate and protect the battery from overheating. In yet another example, the coating may include a heat-resistant or flame-retardant material to prevent the battery from catching fire. In yet another example, the coating may be configured to be rough, thereby increasing the surface area and / or adhesion to the anode material. In yet another example, the coating may include a material with good adhesion or gluing properties to the anode material.

[0047] In some embodiments, one or both of the current collectors 112 and 122 may include a conductive substrate having a rough surface to improve mechanical, electrical, and thermal contact between the anode material and the current collector. The rough surface of the current collector can increase the physical contact area between the anode material and the current collector, thereby increasing the adhesion of the anode material to the current collector. The increased physical contact area can also improve the electrical and thermal contact (e.g., reduced electrical and thermal resistance) between the current collector and the anode material.

[0048] In some embodiments, one or both of the current collectors 112 and 122 may include a porous current collector, such as a wire mesh. The wire mesh (also referred to herein as a mesh) may include any number of filaments that may be assembled in various configurations using a suitable process, such as a regular pattern or structure generated by weaving, braiding, knitting, etc., or a more random pattern or structure generated by randomly distributing the wires and connecting them by welding, adhesives, or other suitable techniques. Moreover, the wires comprising the mesh may be any suitable material. For example, in some embodiments, the wires are metallic, such as steel, aluminum, copper, titanium, or any other suitable metal. In other embodiments, the wires may be conductive non-metallic materials, such as carbon nanofibers or any other suitable material. In some embodiments, the wires may include a coating. For example, the coating may be configured to reduce corrosion and enhance or reduce adhesion properties (e.g., hydrophilic or hydrophobic coatings, respectively). Examples of porous current collectors are described in U.S. Patent Publication No. US 2013 / 0065122 A1, entitled “SEMI-SOLID ELECTRODE CELL HAVING A POROUS CURRENT COLLECTOR AND METHODS OF MANUFACTURE,” the entire disclosure of which is incorporated herein by reference.

[0049] In certain embodiments, separator 130 can be a thinner microporous membrane, which electrically isolates anode 110 from cathode 110, but allows ions to pass through the pores between the two electrolytes during discharge and charge. In certain embodiments, separator 130 includes thermoplastic polymers, such as polyolefins, polyvinyl chloride, nylon, fluorocarbons, and polystyrene. In certain embodiments, separator 130 includes polyolefin materials, such as polyethylene, ultra-high molecular weight polyethylene, polypropylene, polybutylene, polymethylpentene, polyisoprene, copolymers thereof, and compositions thereof. Exemplary compositions may include, but are not limited to, mixtures containing two or more of the following polyethylene, ultra-high molecular weight polyethylene, and polypropylene, and mixtures of the aforementioned substances and copolymers such as ethylene-butene copolymers and ethylene-hexene copolymers.

[0050] The bag 140 in the electrochemical cell 100 basically includes the cathode 110, the cathode current collector 112, the anode 120, the anode current collector 122, and the separator 130. The bag 140 can physically separate the electrochemical cell 100 from adjacent electrochemical cells, thereby reducing or eliminating defect propagation and facilitating easy handling of the electrochemical cell 100 during battery manufacturing. When working with semi-solid electrodes, the bag 140 can also reduce the possibility of ignition of flammable electrolytes during possible welding processes that sometimes produce sparks in battery manufacturing.

[0051] In certain embodiments, cathode 110, cathode current collector 112, anode 120, anode current collector 122, and separator 130 are sealed in bag 140 (e.g., via vacuum sealing). In these embodiments, bag 140 can still reduce or eliminate the chance of exposure to sparks (e.g., from a welding process) that can ignite the electrolyte. A final sealing step can be performed after the welding process to seal one or more single pouch battery cells into an external bag or package, in which case the external bag or package can be used as a humidity control. An example of a battery architecture utilizing a single pouch battery cell is described in U.S. Patent Application Publication No. US 2017-0025646 A1, entitled “SINGLE POUCH BATTERY CELLS AND METHODS OF MANUFACTURE,” the entire disclosure of which is incorporated herein by reference.

[0052] In some embodiments, the bag 140 includes a three-layer structure, that is, an intermediate layer sandwiched between an outer layer and an inner layer, wherein the inner layer is in contact with the electrode and the electrolyte. For example, the outer layer may include a nylon-based polymer film. The inner layer may include a polypropylene (PP) polymer film, which may be resistant to acid corrosion or other electrolyte corrosion and is insoluble in the electrolyte solvent. The intermediate layer may include an aluminum (Al) foil. This structure allows the bag to have high mechanical flexibility and strength.

[0053] In some embodiments, the outer layer of the bag 140 includes a polymer material, such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), nylon, high-density polyethylene (HDPE), oriented polypropylene (o-PP), polyvinyl chloride (PVC), polyimide (PI), polysulfone (PSU), and combinations thereof.

[0054] In certain embodiments, the middle layer of the bag 140 includes a metal layer (foil, substrate, film, etc.) including aluminum (Al), copper (Cu), stainless steel (SUS), alloys thereof, and combinations thereof.

[0055] In certain embodiments, the inner layer of the bag 140 includes a material such as cast polypropylene (c-PP), polyethylene (PE), ethylene vinyl acetate (EVA), and combinations thereof.

[0056] In some embodiments, bag 140 comprises a double-layer structure, i.e., an outer layer and an inner layer. In some embodiments, the outer layer may comprise PET, PBT or other materials as described above. In some embodiments, the inner layer may comprise PP, PE or other materials as described above.

[0057] In some embodiments, bag 140 may include a waterproof layer and / or a gas barrier layer. In some embodiments, the barrier layer may include a metal layer and / or an oxide layer. In some embodiments, it may be beneficial for bag 140 to include an oxide layer because the oxide layer tends to be insulating and can prevent short circuits within the battery.

[0058] In some embodiments, there may be only one (or two) battery cell components within the pouch 140, and the pouch 140 may be substantially thinner than pouches typically used for multiple stacks of battery cells. In some embodiments, the pouch 140 may have a thickness of less than 200 μm, less than 100 μm, or less than 50 μm. In some embodiments, the thickness of the pouch 140 may be defined as the thickness of the film forming the pouch 140.

[0059] In some embodiments, the thickness of the bag 140 can depend on at least two aspects. In some embodiments, it may be desirable to achieve a higher energy density in the resulting battery cell, in which case a thinner bag may be helpful because a larger portion of the space within the battery cell can be reserved for electrode materials. In some embodiments, it may be desirable to maintain or improve the safety advantages of the bag 140. In some embodiments, a thicker bag may help, for example, to reduce the risk of fire. In some embodiments, the bag thickness may be quantified as the ratio of the volume occupied by the bag material to the total volume of the battery cell. In some embodiments, the bag thickness may be about 5% to about 40% in terms of the ratio as defined above. In some embodiments, the bag thickness may be about 10% to about 30% in terms of the ratio as defined above.

[0060] In certain embodiments, the thickness of electrochemical cell 100 (including the thickness of pouch 140 and the thickness of the electrodes) can be about 300 μm to about 3 mm (e.g., about 300 μm, about 400 μm, about 500 μm, about 1 mm, about 2 mm, or about 3 mm, including any values ​​and subranges therebetween).

[0061] In some embodiments, the bag 140 includes a single layer of a lower cost material that can be thinner. In some embodiments, the lower cost material that can be thinner can be a polypropylene or a combination of polyolefins that can be sealed together using heat or pressure (e.g., heat fusion or vacuum sealing).

[0062] In some embodiments, the bag 140 includes a single layer of flame retardant material, thereby preventing the fire hazard from propagating from one single pouch battery cell to another. In some embodiments, the bag 140 includes a gas barrier material, thereby preventing the gas released by one single pouch battery cell from propagating to another, thereby reducing defect propagation.

[0063] The vents 145 in the bag 140 can be created in various ways. In certain embodiments, the vents 145 can be created by thinning portions on the cathode side of the bag 140. When gas is generated within the bag 140 and the gas pressure increases accordingly, the increased pressure can break the thinning portions on the bag, thereby forming an opening (i.e., a vent) in the bag 140.

[0064] The thickness of the thinned portion can depend on the desired threshold pressure at which the vent 145 can be created. In some embodiments, the threshold pressure can be from about 5 psi to about 2000 psi (e.g., about 5 psi, about 10 psi, about 20 psi, about 50 psi, about 100 psi, about 200 psi, about 500 psi, about 1000 psi, or about 2000 psi, including any values ​​and sub-ranges therebetween). In some embodiments, the threshold pressure can be from about 10 psi to about 1000 psi (e.g., about 10 psi, about 20 psi, about 50 psi, about 100 psi, about 200 psi, about 500 psi, or about 1000 psi, including any values ​​and sub-ranges therebetween). In some embodiments, the threshold pressure can be from about 2 psi to about 50 psi (e.g., about 20 psi, about 30 psi, about 40 psi, or about 50 psi, including any values ​​and sub-ranges therebetween).

[0065] In some embodiments, the thinned portion may have a thickness of less than 100 μm (e.g., about 100 μm, about 90 μm, about 80 μm, about 70 μm, about 60 μm, about 50 μm, about 40 μm, about 30 μm, about 20 μm, or about 10 μm, including any values ​​and subranges therebetween). In some embodiments, the ratio of the thickness of the thinned portion compared to the thickness of the rest of the bag 140 may be less than 0.5 (e.g., about 0.5, about 0.4, about 0.3, about 0.2, or about 0.1, including any values ​​and subranges therebetween).

[0066] In some embodiments, the vent 145 can be created by a designated portion that is made of a different material than the material in other portions of the bag 140. For example, the designated portion can be made of a softer material so that increased pressure within the bag 140 can preferentially and selectively damage the designated portion.

[0067] The vent 145 can have a variety of shapes. In some embodiments, the vent 145 can be circular. In some embodiments, the vent 145 can be oval. In some embodiments, the vent 145 can be rectangular or square. In some embodiments, the vent 145 can be a narrow strip opening in the bag 140.

[0068] In some embodiments, the vent 145 can have a lateral dimension of about 1 μm to about 1 mm (e.g., about 1 μm, about 5 μm, about 10 μm, about 20 μm, about 50 μm, about 100 μm, about 200 μm, about 500 μm, or about 1 mm, including any values ​​and sub-ranges therebetween). In some embodiments, the area of ​​the vent 145 can be about 1 μm2 To about 1mm 2 (For example, about 1 μm 2 , about 5 μm 2 , about 10 μm 2 , about 20 μm 2 , about 50 μm 2 , about 100 μm 2 , about 200 μm 2 , about 500 μm 2 or about 1 mm 2 , including any values ​​and subranges therebetween).

[0069] Figures 1A to 1C For illustration purposes, only one vent 145 is shown. In practice, the electrochemical cell 100 may include more than one vent 145. In certain embodiments, the electrochemical cell 100 may include an array of vents.

[0070] In some embodiments, electrochemical cell 100 may include one or more vents 145 located at the bottom of pouch 140 (opposite the side of tabs 115 and 125). In some embodiments, vents 145 may be located at the side edges of pouch 140. In some embodiments, vents 145 may be located on the front surface of the cathode side of pouch 140.

[0071] In some embodiments, the vent 145 may also include a support structure, such as a cross made of a rigid material, to keep the vent 145 open. For example, the bag 140 may be made of a soft material, and the vent 145 may tend to collapse. The use of a support structure may keep the vent 145 open.

[0072] In some embodiments, the vent 145 can be sealable. For example, after the pressure within the bag 140 drops back to a safe level, the vent 145 can collapse back to a sealed state.

[0073] FIG. 2A to FIG. 2CA schematic diagram of an electrochemical cell 200 is shown, which uses a porous separator extending beyond the sealed perimeter of the bag to release the gas generated in the bag. The electrochemical cell 200 includes a cathode 210 arranged on a cathode current collector 212, an anode 220 arranged on an anode current collector 222, and a separator 230 arranged therebetween. The components of the cathode 210, the cathode current collector 212, the anode 220, the anode current collector 222, and the separator 230 are substantially contained in a bag 240, which is sealed along the sealed perimeter 242. The cathode tab 215 is electrically connected to the cathode current collector 212 and extends beyond the bag 240 for connection to an external circuit. Similarly, the anode tab 225 is electrically connected to the anode current collector 215 and extends beyond the bag 240 for connection to an external circuit.

[0074] In certain embodiments, the separator 230 in the electrochemical cell 200 is porous, and at least a portion of the porous separator extends beyond the sealing perimeter 242, such as Figure 2C In this case, the gas in the bag 240 can slowly escape from the bag 240 by passing through the porous separator 230, thereby preventing the pressure in the bag 240 from being excessive.

[0075] The gas release rate (also referred to as the gas leakage rate) may depend on several parameters of the separator 230 , including the porosity of the separator 230 , the pore size of the separator 230 , and the thickness of the separator 230 .

[0076] In certain embodiments, the porosity of separator 230 can be about 1% to about 90% (e.g., about 1%, about 2%, about 5%, about 10%, about 20%, about 50%, about 60%, about 70%, about 80%, or about 90%, including any values ​​and sub-ranges therebetween).

[0077] In some embodiments, the size of the pores in the porous separator can be about 1 μm to about 200 μm (e.g., about 1 μm, about 2 μm, about 5 μm, about 10 μm, about 20 μm, about 50 μm, about 100 μm, about 150 μm, or about 200 μm, including any values ​​and sub-ranges therebetween).

[0078] In certain embodiments, the separator 230 may have a thickness of about 10 μm to about 1 mm (eg, about 10 μm, about 20 μm, about 50 μm, about 100 μm, about 200 μm, about 500 μm, about 750 μm, or about 1 mm, including any values ​​and subranges therebetween).

[0079] In some embodiments, the portion of the separator 230 extending beyond the sealing perimeter 242 can have a length of about 100 μm to about 5 mm (e.g., about 100 μm, about 200 μm, about 500 μm, about 1 mm, about 2 mm, or about 5 mm, including any values ​​and sub-ranges therebetween). In some embodiments, the portion of the separator 230 extending beyond the sealing perimeter 242 can be about 1% to about 25% of the total length of the separator 230 (e.g., about 1%, about 2%, about 5%, about 10%, about 15%, about 20%, or about 25%, including any values ​​and sub-ranges therebetween).

[0080] In some embodiments, only a portion of the separator 230 is porous. For example, a portion around the seal perimeter 242 may be porous, while other portions of the separator 230 may be non-porous. Gas within the bag 240 may escape through the porous portion of the separator 230. This localized porous section may reduce possible interference with the normal function of the separator 230.

[0081] In some embodiments, separator 230 may include a multi-layer structure to construct a gas permeable path within the separator. In this case, the gas within bag 240 may be released from bag 240 via the gas permeable path.

[0082] In some embodiments, separator 230 may include a base layer coated with particles or fibers. The particle coating may be gas permeable. As a result, the gas in bag 240 may be released via the particle coating on the surface of separator 230. In some embodiments, the particles may include ceramic particles and / or fibers. In some embodiments, the ceramic particles may include particles of Al2O3, TiO2, ZrO2, AlO(OH) and / or AlF3, etc.

[0083] In some embodiments, separator 230 may include a base layer coated with other plastic particles and fibers. The plastic coating may be gas permeable. As a result, the gas within bag 240 may be released via the particle coating on the surface of separator 230. In some embodiments, the particles may include polyimide (PI), polyamide-imide (PAI), polyetheretherketone (PEEK), polyethersulfone (PES), polyphenylene sulfide (PPS) and / or phenol polymers, etc.

[0084] In certain embodiments, the particle size may be about 1 μm to about 200 μm (e.g., about 1 μm, about 2 μm, about 5 μm, about 10 μm, about 20 μm, about 50 μm, about 100 μm, about 150 μm, or about 200 μm, including any values ​​and subranges therebetween).

[0085] In certain embodiments, the particle coating may have a thickness of about 1 μm to about 200 μm (e.g., about 1 μm, about 2 μm, about 5 μm, about 10 μm, about 20 μm, about 50 μm, about 100 μm, about 150 μm, or about 200 μm, including any values ​​and subranges therebetween).

[0086] Figure 3 A front view of an electrochemical cell 300 is shown, the electrochemical cell 300 including a degassing tail (also referred to as an auxiliary bag) for regulating gas pressure. The electrochemical cell 300 includes a cathode (not visible from the front view) arranged on a cathode current collector 312, an anode (not visible from the front view) arranged on an anode current collector, and a separator arranged therebetween. The components of the cathode, cathode current collector 312, anode, anode current collector, and separator are substantially contained in a bag 340, the bag 340 being sealed along a sealing perimeter 342. The cathode tab 315 is electrically connected to the cathode current collector 312 and extends beyond the bag 340 for connection to an external circuit. Similarly, the anode tab 325 is electrically connected to the anode current collector and extends beyond the bag 340 for connection to an external circuit.

[0087] The bag 340 includes a degassing tail 345 that is in fluid communication with the rest of the bag 340 that contains the cathode and the anode. Gas generated in the cathode can be contained in the degassing tail 345, thereby regulating the gas pressure within the bag 340.

[0088] In some embodiments, the degassing tail 345 is in direct communication with the rest of the bag 340. In some embodiments, the degassing tail 345 can be separated from the rest of the bag 340 by a pressure regulating membrane. Excess gas pressure in the bag 340 can push the pressure regulating membrane and release the gas into the degassing tail 345. In some embodiments, the boundary between the degassing tail 345 and the rest of the bag 340 can be partially sealed. For example, a series of sealing points can be applied at the boundary between the degassing tail 345 and the rest of the bag 340. In some embodiments, the bag 340 can extend beyond / over the cathode foil tab and the anode foil tab, and the degassing tail 345 is positioned between the cathode tab and the anode tab or is positioned around the cathode tab or the anode tab.

[0089] The degassing tail 345 can have various shapes. In some embodiments, the degassing tail 345 can be rectangular (including square). In some embodiments, the degassing tail 345 can be circular. In some embodiments, the degassing tail 345 can be elliptical. In some embodiments, the degassing tail 345 can be polygonal.

[0090] In certain embodiments, the volume ratio between the deaeration tail 345 and the bag 340 (i.e., the ratio of the volume of the deaeration tail 345 to the volume of the entire bag 340) can be about 5% to about 50% (e.g., about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, or about 50%, including any values ​​and sub-ranges therebetween).

[0091] In some embodiments, the degassing tail 345 can be configured to absorb 20% of the gas produced in the cathode. In some embodiments, the degassing tail 345 can be configured to absorb 30% of the gas produced in the cathode. In some embodiments, the degassing tail 345 can be configured to absorb 40% of the gas produced in the cathode. In some embodiments, the degassing tail 345 can be configured to absorb 50% of the gas produced in the cathode. In some embodiments, the degassing tail 345 can be configured to absorb 60% of the gas produced in the cathode.

[0092] In some embodiments, the degassing tail 345 and the bag 340 can be made of the same material. In some embodiments, the degassing tail 345 and the bag 340 can be made of different materials. For example, the bag 340 can be made of a heat-resistant material, while the degassing tail 345 can be made of a pressure-resistant or flexible material.

[0093] In some embodiments, the degassing tail 345 can be arranged at the top of the bag 340 between the two tabs 315 and 325 (eg, Figure 3 ). In some embodiments, the degassing tail 345 can be arranged at the bottom of the bag 340 opposite to the two protrusions 315 and 325. In some embodiments, the degassing tail 345 can be arranged on the left and / or right side of the bag 340. In some embodiments, the degassing tail 345 can be arranged on the front and / or back side of the bag 340. In some embodiments, the degassing tail 345 can be arranged at the top of the bag 340 outside the cathode or anode.

[0094] In some embodiments, the electrochemical cell 300 may include only one degassing tail. In some embodiments, the electrochemical cell 300 may include more than one degassing tail. For example, the electrochemical cell 300 may include a first degassing tail (e.g., between the two tabs 315 and 325) Figure 3 ) and a second degassing tail at the bottom of the bag 340. In certain embodiments, the electrochemical cell 300 may include a first degassing tail on the left side of the bag 340 and a second degassing tail on the right side of the bag 340.

[0095] FIG. 4A to FIG. 4CA schematic diagram of an electrochemical cell 400 is shown, which includes a circuit interrupting device (CID) in a bag to protect the cell 400 from overvoltage. The electrochemical cell 400 includes a cathode (not visible from the front view) arranged on a cathode current collector 412, an anode (not visible from the front view) arranged on an anode current collector, and a separator arranged therebetween. The assembly of the cathode, cathode current collector 412, anode, anode current collector, and separator is substantially contained in a bag 440, which is sealed along a sealing perimeter 442. The cathode tab 415 is electrically connected to the cathode current collector 412 and extends beyond the bag 440 for connection to an external circuit. Similarly, the anode tab 425 is electrically connected to the anode current collector and extends beyond the bag 440 for connection to an external circuit.

[0096] Figure 4B The cathode tab 415 is shown to include a neck portion 415c between two regular portions: a top portion 415a and a bottom portion 415b. The neck portion 415c has a reduced width compared to the other portions 415a and 415b. Figure 4C The bag 440 is shown to be made of two films 440a and 440b that are sealed by heat sealing. The top portion 415a is coupled to the top sealing area 442a of the first film 440a, and the bottom portion 415b is coupled to the bottom sealing area 442b of the second film 440b. Figure 4C As shown in , top seal area 442a is located above neck portion 415c, and bottom seal area 442b is located below neck portion 415c. Therefore, when gas is generated in bag 440, gas can fill any space in the bag until the seal area (442a and 442b). Since top seal area 442 is higher than bottom seal area 442b, gas can enter the space between film 440a and neck portion 415c. However, because the area exceeds seal area 442b, gas will not enter the space between neck portion 415c and bottom seal area 442b. As a result, gas can apply a force vertical to neck portion 415c. When the force is higher than a threshold value, the force can destroy neck portion 415c and disconnect electrochemical cell 400 from an external circuit, thereby protecting battery 400 and an external circuit.

[0097] In some embodiments, the width ratio of the neck portion 415c to the top portion 415a / bottom portion 415b can be about 0.1 to about 0.9 (e.g., about 0.1, about 0.2, about 0.3, about 0.4, about 0.5, about 0.6, about 0.7, about 0.8, or about 0.9, including any values ​​and sub-ranges therebetween).

[0098] In some embodiments, the absolute width of the neck portion 415c can be about 200 μm to about 2 mm (e.g., about 200 μm, about 300 μm, about 500 μm, about 750 μm, about 1 mm, about 1.2 mm, about 1.4 mm, about 1.6 mm, about 1.8 mm, or about 2 mm, including any values ​​and sub-ranges therebetween).

[0099] In some embodiments, the length of the neck portion 415c can be about 1 mm to about 10 mm (e.g., about 1 mm, about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, or about 10 mm, including any values ​​and sub-ranges therebetween).

[0100] In some embodiments, the neck portion 415c and the top portion 415a / bottom portion 415b may be made of the same material. In some embodiments, the neck portion 415c may be made of a first material, and the top portion 415a / bottom portion 415b may be made of a second material different from the first material. Compared to the second material, the first material may have less mechanical strength, thereby promoting the rupture of the neck portion 415c under the action of an external force.

[0101] In some embodiments, the neck portion 415c may include a bridge connecting the top portion 415a with the bottom portion 415b. In some embodiments, the neck portion 415c may include a plurality of bridges connecting the top portion 415a with the bottom portion 415b.

[0102] Figure 5 A side view of an electrochemical cell 500 is shown, which includes a needle to protect the cell 500 from overpressure. The electrochemical cell 500 includes a cathode 510 arranged on a cathode current collector 512, an anode 520 arranged on an anode current collector 522, and a separator 530 arranged therebetween. The assembly of the cathode 510, the cathode current collector 512, the anode 520, the anode current collector 522, and the separator 530 can be configured to be substantially contained in a bag 540. The bag 540 is in turn configured to be substantially contained in a housing 550. A plurality of needles 555 can be arranged on the inner wall of the housing 550 toward the cathode side of the cell 500. When the bag 540 expands due to gas generation within the bag 540, the needle 555 can open the bag 540, thereby protecting the cell 500 from overpressure.

[0103] In some embodiments, needle 555 can be made of one or more metals. In some embodiments, needle 555 can be made of plastic. In some embodiments, needle 555 can be made of any other rigid material known in the art.

[0104] In some embodiments, needle 555 may include only one needle. In some embodiments, needle 555 may include multiple needles.

[0105] In certain embodiments, the needle 555 can have a length of about 0.5 mm to about 5 mm (eg, about 0.5 mm, about 1 mm, about 2 mm, about 3 mm, about 4 mm, or about 5 mm, including any values ​​and subranges therebetween).

[0106] FIG. 6A to FIG. 6C A safety mechanism is shown according to certain embodiments that employs the layering of electrodes for handling electrochemical cells exceeding a predetermined pressure threshold. FIG. 6A to FIG. 6C , the electrochemical cell 600 includes a cathode 610 disposed on a cathode current collector 612, an anode 620 disposed on an anode current collector 622, and a separator 630 disposed therebetween. The assembly of the cathode 610, the cathode current collector 612, the anode 620, the anode current collector 622, and the separator 630 may be configured to be substantially contained in a bag 640.

[0107] Figure 6B It is shown that the pressure within the bag 640 increases beyond a preset pressure threshold. In this case, the bag 640 can expand, and the anode 620 can be separated from the separator 630, thereby electrically disconnecting the anode 620 from the cathode 610. In this case, the electrochemical cell 600 can be prevented from further charging. In certain embodiments, the cathode 610 can be configured to separate from the separator 630 when the pressure within the bag 640 increases beyond a preset pressure threshold, thereby electrically disconnecting the cathode 610 from the anode 620 and preventing the electrochemical cell 600 from further discharging. In certain embodiments, at least one of the cathode 610 and the anode 620 can be configured to separate from at least one of the cathode current collector 612 and the anode current collector 622 when the pressure within the bag 640 increases beyond a preset pressure threshold, thereby electrically disconnecting the cathode 610 from the anode 620 and preventing the electrochemical cell 600 from further charging and / or discharging.

[0108] Figure 6C It is also shown that the internal pressure within the bag 640 exceeds the threshold pressure. Figure 6CIn the embodiment, a portion 620a of the anode remains coupled to the anode current collector 622 and separated from the separator 630, while another portion 620b of the anode remains attached to the separator 630. This can also at least partially disconnect the electrochemical cell 600 from the external circuit and protect the electrochemical cell 600. In this mechanism, the first area of ​​the stack 620a can be strategically designed to be layered from the first surface (e.g., the current collector), and the second area of ​​the stack 620b can be configured to be layered from the second surface (e.g., the separator 630), thereby separating the cathode 610 and the anode 620 so that they do not maintain electrochemical or electrical contact. In other words, the safety mechanism is designed to physically separate the cathode 610 and the anode 620 so that they are electrochemical cells 600 or operate as electrochemical cells 600. The first area of ​​the stack 620a can include the first part of the cathode 610, the first part of the anode 620, or both. The second area of ​​the stack 620b can include the second part of the cathode 610, the second part of the anode 620, or both.

[0109] In some embodiments, a first portion of cathode 610 or anode 620 may be adhered to cathode current collector 612 or anode current collector 622 using a first adhesive, and may be adhered to separator 630 using a second adhesive, such that the first portion of cathode 610 or anode 620 is configured to be preferentially delaminated from separator 630. In some embodiments, the use of the first adhesive and the second adhesive may be reversed such that the second portion of cathode 610 or anode 620 is configured to be preferentially delaminated from cathode current collector 612 or anode current collector 622.

[0110] Although the above description discusses protective measures with reference to each of the figures individually, more than one measure may be used for a battery. For example, a battery may include a vent (e.g., Figures 1A to 1C ) and porous separators (as shown in FIG. 2A to FIG. 2C In another example, a cell may include a degassing tail (such as Figure 3 ) and CID (as shown in FIG. 4A to FIG. 4C Any other combination is also possible.

Claims

1. A device comprising: A housing for an electrochemical cell, the housing comprising a first portion having a first sealing area and a second portion having a second sealing area, The first portion of the housing is configured to partially define a first cavity configured to receive a cathode, and the second portion of the housing is configured to partially define a second cavity configured to receive an anode; as well as A multilayer structure is arranged between the cathode and the anode and coupled to the first sealing area and the second sealing area, the multilayer structure including a particle coating arranged on the separator, a portion of the multilayer structure extends through the first sealing area and the second sealing area, so that the particle coating creates a fluid flow path from at least one of the first cavity and the second cavity to an area outside the shell.

2. An apparatus according to claim 1, wherein the particle coating forms a gas permeable path on the surface of the separator, and the gas permeable path is configured to release gas from the first cavity or the second cavity to the area outside the shell without interfering with the normal function of the separator.

3. The device according to claim 1, wherein: The particle coating includes ceramic particles.

4. The apparatus of claim 3, wherein the ceramic particles comprise at least one of Al2O3, TiO2, ZrO2, AlO(OH) or AlF3.

5. The apparatus of claim 1, wherein the particle coating comprises plastic particles. 6 . The apparatus according to claim 5 , wherein the plastic particles include at least one of polyimide (PI), polyamide-imide (PAI), polyetheretherketone (PEEK), polyethersulfone (PES), polyphenylene sulfide (PPS), and phenol polymer.

7. The apparatus of claim 1, wherein the particle coating comprises particles having a particle size in a range of about 1 μm to about 200 μm.

8. The apparatus of claim 1, wherein the particle coating comprises a thickness in a range of about 1 μm to about 200 μm.

9. A device comprising: A bag for an electrochemical cell, the bag comprising a first portion having a first sealing area and a second portion having a second sealing area, The first portion of the bag is configured to partially define a first cavity configured to receive a cathode, and the second portion of the bag is configured to partially define a second cavity configured to receive an anode electrically coupled to an anode current collector; as well as A separator is arranged between the cathode and the anode, and the separator is coupled to a portion of the first sealing area and a portion of the second sealing area, the separator includes a degassing tail configured to adjust the gas pressure within the bag, the degassing tail is fluidly connected to at least one of the first cavity and the second cavity, and a portion of the degassing tail extends beyond at least a portion of the first sealing area or the second sealing area.

10. The device according to claim 9, further comprising: A pressure regulating membrane is disposed in at least one of the first sealing area or the second sealing area at a boundary between the degassing tail and the bag, and the pressure regulating membrane is configured to selectively release gas from at least one of the first cavity or the second cavity when the gas pressure in at least one of the first cavity or the second cavity exceeds a threshold.

11. The apparatus of claim 9, wherein the degassing tail comprises a volume, the volume of the degassing tail being in a range of about 5% to about 50% of the volume of the bag.

12. The apparatus of claim 11, wherein the volume of the degassing tail is in the range of about 20% to about 45% of the volume of the bag.

13. The apparatus of claim 9, wherein the degassing tail is configured to absorb at least about 20% of the gas produced by the cathode.

14. The apparatus of claim 13, wherein the degassing tail is configured to absorb at least about 40% of the gas produced by the cathode.

15. The apparatus according to claim 9, further comprising: A porous layer is disposed on the separator, the porous layer creating a fluid flow path between at least one of the first cavity and the second cavity and the degassing tail.

16. A device comprising: A housing for an electrochemical cell, the housing comprising a first portion having a first sealing area and a second portion having a second sealing area, The first portion of the housing is configured to partially define a first cavity configured to receive a cathode, and the second portion of the housing is configured to partially define a second cavity configured to receive an anode; as well as A multilayer structure is arranged between the cathode and the anode and coupled to the first sealing area and the second sealing area, the multilayer structure includes a porous coating arranged on the surface of the separator, a portion of the multilayer structure extends through the first sealing area and the second sealing area, so that the porous coating creates a fluid flow path from at least one of the first cavity and the second cavity to an area outside the shell.

17. The apparatus of claim 16, wherein the porous coating of the multi-layer structure has a porosity of about 1% to about 90%.

18. The apparatus of claim 16, wherein the porous coating layer of the multi-layer structure has pores having a size of about 1 μm to about 200 μm.

19. The apparatus of claim 16, wherein the porous coating of the multi-layer structure is configured to allow gas generated during operation of the electrochemical cell to flow from at least one of the first cavity and the second cavity to the region outside the housing.

20. The apparatus of claim 16, wherein the fluid flow path is configured to communicate with a gas fluid without interfering with normal operation of the electrochemical cell.

21. The apparatus of claim 16, wherein gas is formed in at least one of the following situations: during formation of the electrochemical cell, during normal operation of the electrochemical cell, and when a gas pressure within the housing exceeds a threshold.

22. The apparatus of claim 21, wherein the threshold gas pressure is between about 5 psi and about 2000 psi.

23. The apparatus of claim 21, wherein the threshold gas pressure is greater than about 40% of a predicted gas pressure that would catastrophically fail the electrochemical cell.

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