Electrochemical Cell Monitoring Components

Abstract

The present invention relates to an electrochemical cell monitoring assembly. The monitoring assembly of an electrochemical cell for a secondary lithium battery includes a porous sensing structure and a converter. The porous sensing structure includes a sensing layer disposed on a major surface of a porous separator and a buffer layer disposed between the sensing layer and a facing surface of a negative electrode layer. The buffer layer electrically isolates the sensing layer from the facing surface of the negative electrode layer. The sensing layer includes a conductive material and is configured to generate a response to an input signal or physical stimulus received within the electrochemical cell. The converter is configured to process the response generated by the sensing layer to generate an output signal indicating a diagnostic condition within the electrochemical cell.

Description

Technical Field

[0001] The present invention relates to a monitoring assembly, and more particularly to a monitoring assembly for an electrochemical cell of a secondary lithium battery. Background Art

[0002] A battery is a device that converts chemical energy into electrical energy by means of electrochemical reduction-oxidation (redox) reactions. In secondary or rechargeable batteries, these electrochemical reactions are reversible, which allows the battery to undergo multiple charge and discharge cycles.

[0003] Secondary lithium batteries generally include one or more electrochemical cells that operate by reversibly transferring lithium ions between a negative electrode and a positive electrode. The negative electrode and the positive electrode are generally arranged on opposite sides of a porous polymer separator, and each of the negative electrode and the positive electrode is generally carried on or connected to a metal current collector. The negative electrode and the positive electrode and the polymer separator are permeated with an ion-conducting electrolyte that provides a medium for the conduction of lithium ions through the electrochemical cell between the negative electrode and the positive electrode. In practice, an electrochemical potential is established between the positive and negative electrodes of the electrochemical cell by connecting the corresponding current collectors to each other via a controllable and interruptible external circuit.

[0004] During discharge of the electrochemical cell, the electrochemical potential established between the negative electrode and the positive electrode drives a spontaneous redox reaction within the electrochemical cell and the release of lithium ions and electrons at the negative electrode. The released lithium ions travel from the negative electrode to the positive electrode through the ion-conducting electrolyte, and the electrons travel from the negative electrode to the positive electrode via an external circuit, which produces an electric current. After the negative electrode has been partially or completely depleted of lithium, the electrochemical cell can be charged by connecting the negative electrode and the positive electrode to an external power source, which drives a non-spontaneous redox reaction within the electrochemical cell and the release of lithium ions and electrons from the positive electrode. During charging, the released lithium ions return to the negative electrode and may be plated on the surface of the negative electrode (e.g., on the surface of the negative electrode current collector), inserted or intercalated between the lattice structure of the negative electrode material, or the lithium ions may react with the negative electrode material (e.g., alloying) to form a lithium-containing metallic interphase.

[0005] After repeated discharge and charge cycles, the physical structure of the various components of the electrochemical cell (e.g., the negative and positive electrodes and the porous polymer separator) may be changed. In some cases, it may be desirable to diagnose and / or monitor changes in the physical structure of these components over time during operation of the electrochemical cell. Summary of the invention

[0006] A monitoring assembly for an electrochemical cell of a secondary lithium battery is disclosed. The monitoring assembly may include a porous sensing structure and a converter. The porous sensing structure may be disposed between a major surface of a porous separator and a facing surface of a negative electrode layer. The porous sensing structure may include a sensing layer and a buffer layer. The sensing layer may be disposed on a major surface of the porous separator and may include a conductive material. The sensing layer may be configured to generate a response to an input signal or a physical stimulus. The buffer layer may be disposed between the sensing layer and the facing surface of the negative electrode layer. The buffer layer may be made of an electrically insulating material that electrically isolates the sensing layer from the facing surface of the negative electrode layer. The converter may be configured to process a response generated by the sensing layer to generate an output signal indicating a diagnostic condition of the porous separator or the negative electrode layer.

[0007] The conductive material of the sensing layer may include particles of at least one of nickel, copper, titanium, silver, gold or carbon.

[0008] The electrically insulating material of the buffer layer may include at least one of Al2O3, SiO2, ZrO2, TiO2, ZnO, Ta2O5, La2O5, HfO, lithium lanthanum zirconium oxide, zeolite, polytetrafluoroethylene, aluminum alkoxide, zirconium alkoxide, titanium alkoxide or diamond-like carbon.

[0009] The transducer may be configured to process the response generated by the sensing layer into an electrical signal, an electromagnetic signal, or a mechanical signal.

[0010] The transducer may be an antenna or a resonator. In such a case, the transducer may be integrated into the sensing layer by patterning the conductive material of the sensing layer in the form of an antenna or a resonator.

[0011] The transducer may be physically separated from the sensing layer. In such a case, the transducer may be electrically coupled to the sensing layer via an electrical circuit.

[0012] The output signal generated by the transducer is indicative of the formation of lithium dendrites extending from the facing surface of the negative electrode layer and penetrating the sensing layer.

[0013] The porous sensing structure may include a first sensing layer disposed on a major surface of the porous separator, a first buffer layer covering the first sensing layer, a second sensing layer covering the first buffer layer, and a second buffer layer covering the second sensing layer on a major surface of the porous separator. In such a case, the output signal generated by the converter may indicate the formation of lithium dendrites extending from the facing surface of the negative electrode layer and penetrating the first sensing layer. The output signal generated by the converter may indicate the growth rate of the lithium dendrites.

[0014] The output signal generated by the transducer may be indicative of the resistance of the sensing layer. In such a case, the output signal generated by the transducer may be indicative of a compressive or tensile force applied to the sensing layer resulting in a physical deformation of the sensing layer.

[0015] The monitoring assembly may include a microcontroller configured to process the output signal generated by the transducer into data and store the data as a function of time in a local memory. In such a case, the microcontroller may be electrically coupled to the sensing layer via the circuit.

[0016] An electrochemical cell of a secondary lithium battery is disclosed. The electrochemical cell may include: a positive electrode layer electrically connected to a positive electrode current collector; a negative electrode layer spaced apart from the positive electrode layer and electrically connected to a negative electrode current collector; a porous separator disposed between the positive electrode layer and the negative electrode layer; and a monitoring assembly. The porous separator may be disposed between the positive electrode layer and the negative electrode layer and may have a first major surface and an opposing second major surface. The first major surface of the porous separator may face a facing surface of the negative electrode layer. The monitoring assembly may include a porous sensing structure and a transducer. The porous sensing structure may be disposed between the first major surface of the porous separator and the facing surface of the negative electrode layer. The porous sensing structure may include a sensing layer and a buffer layer. The sensing layer may be disposed on the first major surface of the porous separator and may include a conductive material. The sensing layer may be configured to respond to an input signal or a physical stimulus. The buffer layer may be disposed between the sensing layer and the facing surface of the negative electrode layer. The buffer layer may be made of an electrically insulating material that electrically isolates the sensing layer from the facing surface of the negative electrode layer. The transducer may be configured to process a response produced by the sensing layer to generate an output signal indicative of a diagnostic condition within the electrochemical cell.

[0017] The electrochemical cell may include a microcontroller configured to process the output signal generated by the converter into data and store the data in a local memory as a function of time. The microcontroller may be electrically coupled to the negative electrode current collector via a first electrical connector and may be electrically coupled to the positive electrode current collector via a second electrical connector. In such a case, the microcontroller may be powered by the potential difference between the negative electrode current collector and the positive electrode current collector.

[0018] The porous separator and the porous sensing structure may be infiltrated with a non-aqueous liquid electrolyte solution.

[0019] The sensing layer may include an electrochemically active reference electrode material. In such a case, the electrochemically active reference electrode material may include at least one metal oxide of lithium iron phosphate, lithium titanium oxide, or lithium nickel manganese cobalt oxide.

[0020] The porous separator may be made of an ion-conducting polymer material. In this case, the ion-conducting polymer material may include at least one of polyethylene, polypropylene, polyamide, polytetrafluoroethylene, polyvinylidene fluoride or polyvinyl chloride.

[0021] The negative electrode layer may include at least one of graphite or silicon. Alternatively, the negative electrode layer may include a layer of lithium metal. In such a case, the layer of lithium metal may include greater than 97% lithium by weight.

[0022] The present invention also provides the following scheme:

[0023] Solution 1. A monitoring assembly for an electrochemical cell of a secondary lithium battery, the assembly comprising:

[0024] a porous sensing structure disposed between a major surface of the porous separator and a facing surface of the negative electrode layer, the porous sensing structure comprising:

[0025] a sensing layer disposed on the major surface of the porous separator, the sensing layer comprising a conductive material and configured to respond to an input signal or a physical stimulus, and

[0026] a buffer layer disposed between the sensing layer and the facing surface of the negative electrode layer, the buffer layer being made of an electrically insulating material that electrically isolates the sensing layer from the facing surface of the negative electrode layer; and

[0027] A transducer is configured to process the response produced by the sensing layer to generate an output signal indicative of a diagnostic condition of the porous separator or the negative electrode layer.

[0028] Option 2. The component according to Option 1, wherein the conductive material of the sensing layer comprises particles of at least one of nickel, copper, titanium, silver, gold or carbon.

[0029] Option 3. A component according to Option 1, wherein the electrically insulating material of the buffer layer includes at least one of the following: Al2O3, SiO2, ZrO2, TiO2, ZnO, Ta2O5, La2O5, HfO, lithium lanthanum zirconium oxide, zeolite, polytetrafluoroethylene, aluminum alkoxide, zirconium alkoxide, titanium alkoxide or diamond-like carbon.

[0030] Embodiment 4. The component according to embodiment 1, wherein the transducer is configured to process the response generated by the sensing layer into an electrical signal, an electromagnetic signal, or a mechanical signal.

[0031] Option 5. The component according to Option 1, wherein the transducer is an antenna or a resonator, and wherein the transducer is integrated into the sensing layer by patterning the conductive material of the sensing layer into the form of the antenna or the resonator.

[0032] Embodiment 6. The assembly of embodiment 1, wherein the transducer is physically separated from the sensing layer and electrically coupled to the sensing layer via an electrical circuit.

[0033] Embodiment 7. The assembly of embodiment 1, wherein the output signal generated by the transducer indicates the formation of lithium dendrites extending from the facing surface of the negative electrode layer and penetrating the sensing layer.

[0034] Embodiment 8. The assembly according to embodiment 1, wherein the porous sensing structure comprises:

[0035] A first sensing layer is disposed on the major surface of the porous separator, a first buffer layer covers the first sensing layer, a second sensing layer covers the first buffer layer, and a second buffer layer covers the second sensing layer on the major surface of the porous separator.

[0036] Option 9. A component according to Option 8, wherein the output signal generated by the converter indicates the formation of lithium dendrites extending from the facing surface of the negative electrode layer and penetrating the first sensing layer, and wherein the output signal generated by the converter indicates the growth rate of the lithium dendrites.

[0037] Embodiment 10. The assembly of embodiment 1, wherein the output signal generated by the transducer is indicative of a resistance of the sensing layer.

[0038] Embodiment 11. The assembly of embodiment 10, wherein the output signal generated by the transducer is indicative of a compressive force or a tensile force applied to the sensing layer that results in a physical deformation of the sensing layer.

[0039] Scheme 12. The component according to Scheme 1 further comprises:

[0040] A microcontroller is configured to process the output signal generated by the converter into data and store the data as a function of time in a local memory.

[0041] Embodiment 13. The component of embodiment 12, wherein the microcontroller is electrically coupled to the sensing layer via an electrical circuit.

[0042] Scheme 14. An electrochemical cell of a secondary lithium battery, the electrochemical cell comprising:

[0043] a positive electrode layer electrically coupled to a positive electrode current collector;

[0044] a negative electrode layer spaced apart from the positive electrode layer and electrically coupled to a negative electrode current collector;

[0045] a porous separator disposed between the positive electrode layer and the negative electrode layer and having a first major surface and an opposing second major surface, the first major surface of the porous separator facing a facing surface of the negative electrode layer; and

[0046] Monitoring components, including:

[0047] a porous sensing structure disposed between the first major surface of the porous separator and the facing surface of the negative electrode layer, the porous sensing structure comprising:

[0048] a sensing layer disposed on the first major surface of the porous separator, the sensing layer comprising a conductive material and configured to respond to an input signal or a physical stimulus, and

[0049] a buffer layer disposed between the sensing layer and the facing surface of the negative electrode layer, the buffer layer being made of an electrically insulating material that electrically isolates the sensing layer from the facing surface of the negative electrode layer; and

[0050] A transducer is configured to process the response produced by the sensing layer to generate an output signal indicative of a diagnostic condition within the electrochemical cell.

[0051] Scheme 15. The electrochemical cell according to Scheme 14, further comprising:

[0052] A microcontroller is configured to process the output signal generated by the converter into data and store the data as a function of time in a local memory.

[0053] Option 16. An electrochemical cell according to Option 15, wherein a microcontroller is electrically connected to the negative electrode collector via a first electrical connector and electrically connected to the positive electrode collector via a second electrical connector, and wherein the microcontroller is powered by a potential difference between the negative electrode collector and the positive electrode collector.

[0054] Embodiment 17. The electrochemical cell according to embodiment 14, wherein the porous separator and the porous sensing structure are permeated with a non-aqueous liquid electrolyte solution.

[0055] Embodiment 18. The electrochemical cell according to embodiment 14, wherein the sensing layer comprises an electrochemically active reference electrode material, and the electrochemically active reference electrode material comprises at least one metal oxide selected from the group consisting of lithium iron phosphate, lithium titanium oxide, or lithium nickel manganese cobalt oxide.

[0056] Option 19. An electrochemical cell according to Option 14, wherein the porous separator is made of an ion-conductive polymer material, and wherein the ion-conductive polymer material comprises at least one of polyethylene, polypropylene, polyamide, polytetrafluoroethylene, polyvinylidene fluoride or polyvinyl chloride.

[0057] Scheme 20. The electrochemical cell according to Scheme 14, wherein the negative electrode layer comprises:

[0058] At least one of graphite or silicon, or

[0059] A layer of lithium metal, and wherein the layer of lithium metal comprises greater than 97% lithium by weight.

[0060] The above summary of the invention is not intended to represent every possible embodiment or every aspect of the present disclosure. Rather, the foregoing summary of the invention is intended to illustrate some of the novel aspects and features disclosed herein. The above features and advantages of the present disclosure and other features and advantages will be readily apparent from the following detailed description of representative embodiments and modes for implementing the present disclosure when taken in conjunction with the accompanying drawings and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Illustrative embodiments will hereinafter be described with reference to the accompanying drawings, wherein like reference numerals refer to like elements, and in which:

[0062] Figure 1 is a schematic side cross-sectional view of an electrochemical cell of a secondary lithium battery, the electrochemical cell including a monitoring assembly that uses a porous sensing structure in combination with a transducer to diagnose and / or monitor a specific condition within the electrochemical cell, wherein the porous sensing structure includes a sensing layer disposed on a major surface of a porous separator and a buffer layer electrically isolating the sensing layer from a facing surface of a layer of negative electrode material;

[0063] Figure 2 According to one or more embodiments Figure 1 During the assembly of the electrochemical cell Figure 1 A schematic side cross-sectional view of a porous sensing structure;

[0064] Figure 3is a schematic side cross-sectional view of a portion of an electrochemical cell including a monitoring assembly that uses a porous sensing structure in combination with a transducer to diagnose and / or monitor a particular condition within the electrochemical cell, wherein the porous sensing structure includes a first sensing layer disposed on a major surface of a porous separator, a first buffer layer overlying the first sensing layer, a second sensing layer overlying the first buffer layer, and a second buffer layer overlying the second sensing layer, and wherein the monitoring assembly is configured to diagnose and monitor lithium dendrite formation and growth within the electrochemical cell;

[0065] Figure 4 is a schematic side cross-sectional view of a portion of an electrochemical cell including a monitoring assembly that uses a porous sensing structure in combination with a transducer to diagnose and / or monitor a particular condition within the electrochemical cell, wherein the porous sensing structure includes a sensing layer and a buffer layer, and wherein the transducer is integrated into the physical configuration of the sensing layer; and

[0066] Figure 5 , Figure 6 and Figure 7 is a schematic side cross-sectional view of a portion of an electrochemical cell, comprising a monitoring assembly that uses a porous sensing structure in combination with a transducer to diagnose and / or monitor specific conditions within the electrochemical cell, wherein the porous sensing structure comprises a sensing layer and a buffer layer, the transducer is integrated into the physical structure of the sensing layer, and wherein the monitoring assembly is configured to diagnose volume changes of a porous separator and / or negative electrode material layer of the electrochemical cell.

[0067] The present disclosure allows for modifications and alternative forms, and is shown by way of example in the accompanying drawings and a representative embodiment is described in detail below. The inventive aspects of the present disclosure are not limited to the specific forms disclosed. Rather, the present disclosure is intended to cover modifications, equivalents, combinations, and alternatives that fall within the scope of the present disclosure as defined by the appended claims. DETAILED DESCRIPTION

[0068] The currently disclosed monitoring assembly can be incorporated into an electrochemical cell and is used to monitor one or more diagnostic conditions of the electrochemical cell. The currently disclosed monitoring assembly includes a porous sensing structure placed between the negative electrode layer and the porous separator layer of the electrochemical cell, which includes a sensing layer and a buffer layer. The sensing layer includes a conductive material and is configured to respond to a specific input signal or other stimulus. The monitoring assembly also includes a converter, which is configured to convert or otherwise process the response generated by the sensing layer into an output signal that can be used to diagnose a specific condition in the electrochemical cell. In the assembly, the buffer layer is placed between the sensing layer and the negative electrode layer and electrically isolates the sensing layer from the negative electrode layer during operation of the electrochemical cell.

[0069] In embodiments, the monitoring assembly disclosed herein may be configured to diagnose the formation of lithium dendrites on the surface of the negative electrode layer and may be configured to determine the penetration depth of the lithium dendrites and / or track the growth rate of the lithium dendrites. Additionally or alternatively, the monitoring assembly disclosed herein may be configured to diagnose volume changes (e.g., expansion) of the negative electrode layer and / or the porous separator layer. In some embodiments, the sensing layer may be configured to be used as a reference when measuring the individual electrochemical potentials of the negative electrode layer and the positive electrode layer of the electrochemical cell.

[0070] The converter can be physically incorporated into the electrochemical cell, for example by being integrated with the sensing layer or by being incorporated into a microcontroller associated with the electrochemical cell. In other embodiments, the converter can be part of an external control device that is electrically connected to the sensing layer or otherwise communicates. In embodiments where the electrochemical cell is combined with one or more electrochemical cells to form a secondary lithium battery, the external control device can be in the form of a battery controller, and the secondary lithium battery and the battery controller together can form a battery system that supplies power to the electric machine. In other embodiments, such as in a laboratory environment, the external control device can be in the form of a battery test or calibration machine, and the converter can be part of the battery test or calibration machine.

[0071] As used herein, the term "transducer" means a device or structure that receives an input signal or stimulus (in one form of energy) and, in response to the input signal or stimulus, produces an output signal, which may be in another form of energy.

[0072] Figure 1 A schematic side cross-sectional view of an electrochemical cell 10 is depicted, which can be combined with one or more additional electrochemical cells to form a secondary battery, such as a lithium ion or lithium metal battery (sometimes referred to herein simply as a "lithium battery"). The electrochemical cell 10 includes a positive electrode 12, a negative electrode 14, a porous separator 16 that electrically isolates the positive and negative electrodes 12, 14 from each other, and a monitoring assembly 18, which includes a porous sensing structure 19 disposed between and electrically isolated from the positive and negative electrodes 12, 14. The positive electrode 12 includes a layer of positive electrode material 20 deposited on a major surface of a positive electrode current collector 22, and the negative electrode 14 includes a layer of negative electrode material 24 deposited on a major surface of a negative electrode current collector 26. In practice, the positive and negative electrode current collectors 22, 26 can be electrically coupled to a power source or load 28 via an external circuit 30.

[0073] The positive electrode material layer 20 may include one or more electrochemically active materials capable of undergoing a reversible redox reaction with lithium, such as a material capable of sufficient lithium intercalation and deintercalation, alloying and dealloying, or plating and stripping.

[0074] The negative electrode material layer 24 may be an electrochemically active material that undergoes a reversible redox reaction with lithium during operation of the electrochemical cell 10, and / or the negative electrode material layer 24 may include a layer of lithium (Li) metal or a lithium metal alloy. In some embodiments, the negative electrode material layer 24 may be substantially composed of lithium metal and may include greater than 97% lithium or more preferably greater than 99% lithium by weight. In other embodiments, the negative electrode material layer 24 may include a material that is capable of undergoing reversible insertion or intercalation of lithium ions or capable of reacting with lithium to form a lithium-containing intermetallic compound. For example, in such a case, the negative electrode material layer 24 may include graphite, silicon, or a silicon alloy.

[0075] The positive and negative electrode current collectors 22 , 26 may include a material (eg, a metal or metal alloy) that is capable of collecting free electrons and reversibly transferring them into and out of the respective electrode material layers 20 , 24 .

[0076] The porous separator 16 is positioned between the positive electrode 12 and the porous sensing structure 19 of the monitoring component 18. The porous separator 16 has a first main surface 32 facing the positive electrode 12 and a second main surface 34 facing the porous sensing structure 19 and the negative electrode 14. The porous separator 16 presents an open microporous structure and can include organic and / or inorganic materials that can physically separate and electrically insulate the positive and negative electrode material layers 20, 24 from each other while allowing ions to flow freely between them. The porous separator 16 may include a non-woven material, for example, a sheet, a mesh or a felt made of oriented or randomly oriented fibers. The porous separator 16 may include a microporous polymer material, such as a microporous polyolefin-based membrane or film. For example, the porous separator 16 may include a single polyolefin or a combination of polyolefins, such as polyethylene (PE), polypropylene (PP), polyamide (PA), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF) and / or polyvinyl chloride (PVC). In one form, the porous separator 16 may comprise a laminate of one or more polymeric materials, such as a laminate of PE and PP. The porous separator 16 may have a thickness in the range of 5 μm to 30 μm and a porosity in the range of 25% to 75%.

[0077] In the assembly, the porous separator 16, the porous sensing structure 19 of the monitoring assembly 18, and the positive and negative electrode material layers 20, 24 of the electrochemical cell 10 may be infiltrated with an electrolyte (not shown). The electrolyte may include a material capable of effectively conducting lithium ions through the porous separator 16 and the porous sensing structure 19 and between the positive electrode material layer 20 and the negative electrode material layer 24 during operation of the electrochemical cell 10. For example, the electrolyte may include a non-aqueous liquid electrolyte. In such a case, the non-aqueous liquid electrolyte may include a solution including a lithium salt dissolved or ionized in a non-aqueous aprotic organic solvent or a mixture of non-aqueous aprotic organic solvents. Some suitable lithium salts that may be used to make the electrolyte include LiClO4, LiAlCl4, LiI, LiBr, LiSCN, LiBF4, LiB(C6H5)4, LiAsF6, LiCF3SO3, LiN(CF3SO2)2, LiPF6, and combinations thereof. The non-aqueous protonic organic solvent in which the lithium salt is dissolved may be a cyclic carbonate (i.e., ethylene carbonate, propylene carbonate), an acyclic carbonate (i.e., dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate), an aliphatic carboxylic acid ester (i.e., methyl formate, methyl acetate, methyl propionate), a γ-lactone (i.e., γ-butyrolactone, γ-valerolactone), an acyclic ether (i.e., 1,2-dimethoxyethane, 1,2-diethoxyethane, ethoxymethoxyethane), a cyclic ether (i.e., tetrahydrofuran, 2-methyltetrahydrofuran), or a combination thereof. As another example, the non-aqueous electrolyte may include a gel or plasticized polymer electrolyte. In such a case, the non-aqueous electrolyte may include a polymer host material soaked with a non-aqueous liquid electrolyte solution. Some examples of suitable polymer host materials include polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), polyethylene oxide (PEO), polyacrylates, and polyvinylidene fluoride hexafluoropropylene (PVdF-HFP).

[0078] The monitoring assembly 18 is configured to diagnose and / or monitor specific conditions of the electrochemical cell 10 that can affect the performance and / or cycle life of the electrochemical cell 10 without interfering with the operation of the electrochemical cell 10, specifically, without inhibiting the free flow of ions between the positive and negative electrode material layers 20, 24. In the monitoring assembly 18, the porous sensing structure 19 cooperates with at least one transducer 42 to sense and / or transmit information about the electrochemical cell 10 and / or its components that can be used to diagnose specific conditions of the electrochemical cell 10. The porous sensing structure 19 includes at least one sensing layer 36 and at least one buffer layer 38, the buffer layer 38 electrically isolating the sensing layer 36 from the facing surface 40 of the negative electrode material layer 24.

[0079] The sensing layer 36 is disposed on the second major surface 34 of the porous separator 16 and the buffer layer 38 is disposed between the sensing layer 36 and the facing surface 40 of the negative electrode material layer 24. Figure 1 , the transducer 42 is depicted as being physically separated from the sensing layer 36 and electrically coupled to the sensing layer 36 via an electrical connector 44; however, this is not required. In other embodiments, the transducer 42 may be integrated into the physical construction of the sensing layer 36. In addition, in embodiments where the transducer 42 is physically separated from the sensing layer 36, the transducer 42 may communicate wirelessly with the sensing layer 36, for example, via transmission and / or reception of electromagnetic signals (e.g., radio frequency (RF) radio waves, such as ultra-high frequency (UHF) radio waves). In some embodiments, the transducer 42 may be part of a microcontroller 46 associated with the electrochemical cell 10. The microcontroller 46 (also referred to as a microcontroller unit) may be in the form of an integrated circuit that includes a central processing unit (CPU), random access memory (RAM), flash memory, read-only memory (ROM), and / or input / output (I / O) devices. The microcontroller 46 may be associated with the electrochemical cell 10, for example, by being physically incorporated into a housing or case (not shown) of the electrochemical cell 10. In other embodiments, the converter 42 may be part of an external control device (not shown) associated with the battery or another host. The external control device may be a computer including a central processing unit in the form of a microprocessor, memory, and one or more peripheral devices (e.g., a monitor and / or battery testing device).

[0080] The converter 42 and / or microcontroller 46 may optionally be electrically coupled to the positive electrode current collector 22 and the negative electrode current collector 26 via the circuit 48, and the inherent potential between the current collectors 22, 26 may supply power for the operation of the converter 42 and / or microcontroller 46. In other embodiments, power may be supplied to the sensing layer 36, the converter 42, and / or the microcontroller 46 by another power source as needed.

[0081] The sensing layer 36 is porous and configured to assist in diagnosing and / or monitoring specific conditions within the electrochemical cell 10 without interfering with the operation of the electrochemical cell 10, for example, without inhibiting the free flow of lithium ions therethrough. The sensing layer 36 is configured to generate a response to an input signal or another stimulus received within the electrochemical cell 10. For example, the sensing layer 36 may be configured to generate a response when exposed to an energy source (e.g., an applied voltage, current, and / or electromagnetic wave) or when subjected to a physical force (e.g., a compressive force or a tensile force) that may or may not cause a physical deformation of the sensing layer 36. The response generated by the sensing layer 36 may be an electromagnetic signal (e.g., a radio wave), a mechanical signal (e.g., an acoustic signal), an electric current, an electric field, a magnetic field, a change in shape, or other response types that can be used, for example, by a transducer 42, a microcontroller 46, and / or an external control device to diagnose a specific condition within the electrochemical cell 10. For example, the response generated by the sensing layer 36 may be used to diagnose lithium dendrite growth on the facing surface 40 of the negative electrode material layer 24, and optionally indicate the extent and growth rate of the lithium dendrite growth. Additionally or alternatively, the response generated by the sensing layer 36 can be used to diagnose a volume change of the porous separator 16 and / or the negative electrode material layer 24. When the porous separator 16, the negative electrode material layer 24, and / or another component of the electrochemical cell 10 undergoes a change in volume (i.e., an expansion or contraction in volume), the change in volume can exert a compressive or tensile force on the sensing layer 36, which ultimately causes deformation of the sensing layer 36.

[0082] The sensing layer 36 includes at least one conductive material, and the function of the sensing layer 36 can be predetermined based on the way the conductive material is physically arranged in the sensing layer 36. In some embodiments, the sensing layer 36 (and its conductive material) can extend in a substantially continuous layer between the porous separator 16 and the negative electrode material layer 24, and its size can be comparable to the area of ​​the facing surface 40 of the negative electrode material layer 24. In other embodiments, the sensing layer 36 (and its conductive material) can be arranged in the form of one or more patterns or physical structures that can be used as a transducer (e.g., an antenna, a capacitor, an inductor, a resistor, or a resonator) when exposed to an energy source. In the sensing layer 36, the at least one conductive material can be combined with one or more additional materials, which can, for example, assist in depositing or adhering the sensing layer 36 on the second main surface 34 of the porous separator 16 or on the facing surface 40 of the negative electrode material layer 24, on the buffer layer 38.

[0083] The conductive material of the sensing layer 36 may include at least one of nickel, copper, titanium, silver, gold or carbon or be substantially composed thereof. In practice, the pores of the porous sensing layer 36 may be infiltrated with electrolytes. Without considering the weight of the electrolyte in the pores of the sensing layer 36, the conductive material may account for 50% to 100% of the sensing layer 36 by weight and more preferably greater than 90% of the sensing layer 36. The sensing layer 36 may be deposited on the second main surface 34 of the porous separator 16 or on the facing surface 40 of the negative electrode material layer 24, on the buffer layer 38 using a printing process (e.g., inkjet printing, aerosol printing, screen printing or a low-speed plasma jet printing process), magnetron sputtering, ion beam sputtering, thermal evaporation process or electroless deposition or plating technology. The sensing layer 36 may have a thickness in the range of 10 nanometers to 1 micrometer or more preferably in the range of 25 nanometers to 200 nanometers. The thickness and density of the sensing layer 36 may be selected such that the sensing layer 36 is thick enough and dense enough to form at least one continuous conductive path therethrough without inhibiting the free flow of lithium ions.

[0084] In some embodiments, the sensing layer 36 can be used as a reference for monitoring the potential of the positive and negative electrode material layers 20, 24. In such cases, the sensing layer 36 can include a reference electrode material, such as lithium iron phosphate, lithium titanium oxide, and / or lithium nickel manganese cobalt oxide, in addition to the conductive material. The reference electrode material can be dispersed throughout the sensing layer 36 or can be in the form of a separate layer covering the sensing layer 36 (or below it).

[0085] The buffer layer 38 is porous and is configured to electrically isolate the sensing layer 36 from the facing surface 40 of the negative electrode material layer 24 without inhibiting the free flow of lithium ions therethrough. The buffer layer 38 may include or be substantially composed of at least one electrically insulating material. The electrically insulating material of the buffer layer 38 may include at least one of the following: an electrically insulating ceramic material (e.g., Al2O3, SiO2, ZrO2, TiO2, ZnO, Ta2O5, La2O5, HfO, lithium lanthanum zirconium oxide (Li-La-Zr-O) or zeolite), an electrically insulating polymer material (e.g., polytetrafluoroethylene), an electrically insulating composite material (e.g., aluminum alkoxide, zirconium alkoxide, titanium alkoxide) and / or diamond-like carbon. In the buffer layer 38, the electrically insulating material may be combined with one or more additional materials, which may, for example, assist in depositing or adhering the buffer layer 38 on the second main surface 34 of the porous separator 16, on the sensing layer 36, or on the facing surface 40 of the negative electrode material layer 24. In practice, the pores in the porous buffer layer 38 may be infiltrated with electrolyte. Without considering the weight of the electrolyte in the pores of the buffer layer 38, the electrically insulating material may account for 50% to 100% of the buffer layer 38 by weight, preferably more than 90% of the buffer layer 38.

[0086] Using an atomic layer deposition process, a molecular layer deposition process, sputtering, a thermal evaporation process, or an ion beam deposition process, the buffer layer 38 can be deposited on the second major surface 34 of the porous separator 16, on the sensing layer 36, or the buffer layer 38 can be deposited on the facing surface 40 of the negative electrode material layer 24. The buffer layer 38 can have a thickness in the range of 5 nanometers to 100 micrometers. The thickness and density of the buffer layer 38 can be selected so that the buffer layer 38 is thick enough and dense enough to effectively electrically isolate the sensing layer 36 from the negative electrode material layer 24 without inhibiting the free flow of lithium ions therethrough.

[0087] In the assembly, the sensing layer 36 and the buffer layer 38 of the porous sensing structure 19 may be deposited or otherwise formed on the second major surface 34 of the porous separator 16 or on the facing surface 40 of the negative electrode material layer 24 before the porous sensing structure 19 is sandwiched between the facing surface 40 of the negative electrode material layer 24 and the second major surface 34 of the porous separator 16. The porous sensing structure 19 may be deposited on the porous separator 16 or the negative electrode material layer 24, for example, using a continuous roll-to-roll process. In embodiments where the porous sensing structure 19 is deposited on the porous separator 16, the sensing layer 36 may be deposited on the second major surface 34 of the porous separator 16 and then the buffer layer 38 may be deposited on the second major surface 34 of the porous separator 16, above the sensing layer 36.

[0088] Reference now Figure 2 , in an embodiment where the porous sensing structure 19 is deposited on the negative electrode material layer 24, the buffer layer 38 may be deposited on the facing surface 40 of the negative electrode material layer 24 and then the sensing layer 36 may be deposited on the facing surface 40 of the negative electrode material layer 24, over the buffer layer 38. In such a case, the spacer 70 may be deposited or positioned on at least a portion of the negative electrode current collector 26 that extends beyond the negative electrode material layer 24 before the porous sensing structure 19 is deposited on the negative electrode material layer 24 and the spacer 70 over the negative electrode current collector 26. The spacer 70 may be made of an electrically insulating material and / or a sacrificial material that may be removed from the negative electrode current collector 26 after the porous sensing structure 19 is formed on the negative electrode material layer 24.

[0089] The transducer 42 is configured to transform or otherwise process the response generated by the sensing layer 36 into an output signal (e.g., an electrical signal, an electromagnetic signal, or a mechanical signal) that represents or indicates one or more diagnostic conditions within the electrochemical cell 10. The output signal generated by the transducer 42 can be a signal that can be further processed by the microcontroller 46 or an external control device to diagnose a specific condition of the electrochemical cell 10. The transducer 42 can be an antenna, a resonator, a potential difference sensor (e.g., a voltage sensor, a voltmeter, or an electrometer), a current sensor (e.g., a galvanometer or an ammeter), a resistance sensor (e.g., an ohmmeter or a Wheatstone bridge), an analog-to-digital converter, or a digital-to-analog converter. The transducer 42 can be an inductive sensor (inductor), a capacitive sensor (capacitor), and / or a resistive sensor (resistor). The antenna can transform or convert electromagnetic radiation (e.g., radio waves) into an electrical signal (which can be processed by another device such as a receiver) and can transform or convert an electrical signal emitted by another device (e.g., a transmitter) into electromagnetic radiation (e.g., radio waves). A voltage sensor can convert a measured potential difference between two points in a circuit into an output signal. A current sensor can convert a measured current flowing through a conductive path into an output signal. An analog-to-digital converter can convert an analog signal into a digital signal, and a digital-to-analog converter can convert a digital signal into an analog signal.

[0090] Figure 1The monitoring assembly 18 depicted in FIG. 1 can be configured to diagnose the formation of a lithium dendrite 50 on the facing surface 40 of the negative electrode material layer 24, which has grown through the buffer layer 38 and penetrated the sensing layer 36. In such a case, the transducer 42 can be in the form of a potential difference sensor, a current sensor, or other type of sensor or actuator whose output signal can be used to diagnose the formation of the lithium dendrite 50. Before the formation of the lithium dendrite 50, the transducer 42 can continuously or periodically sense the potential difference between the sensing layer 36 and the negative electrode material layer 24, or the transducer 42 can sense the current flowing through the sensing layer 36. In addition, the transducer 42 can periodically or continuously transmit an output signal indicating or representing the sensed potential difference or current to the microcontroller 46 or an external control device, which can process the output signal transmitted by the transducer 42 into data that can be stored and / or used to diagnose the formation of the lithium dendrite 50. For example, the microcontroller 46 can process the output signal generated by the transducer 42 into data and store the data as a function of time in a local memory. When the lithium dendrite 50 penetrates the sensing layer 36, the lithium dendrite 50 can complete the circuit between the sensing layer 36 and the negative electrode material layer 24, which will inevitably change the potential difference between the sensing layer 36 and the negative electrode material layer 24 and the amount of current flowing through the sensing layer 36. In such a case, by comparing the recent data received from the converter 42 with the historical data stored in the memory and calculating the difference between the recent data and the historical data, the microcontroller 46 can positively diagnose the formation of the lithium dendrite 50. If the microcontroller 46 determines that the potential difference between the sensing layer 36 and the negative electrode material layer 24 has been significantly reduced, or if the current flowing through the sensing layer 36 has been significantly increased, the microcontroller 46 can positively diagnose the formation of the lithium dendrite 50.

[0091] Figure 3 Another embodiment of a monitoring assembly 118 is depicted that can be used to diagnose and / or monitor an electrochemical cell of a secondary lithium ion or lithium metal battery (such as Figure 1 The monitoring component 118 is similar in many respects to the Figure 1 The monitoring components 18 described in the foregoing description are generally not repeated here. Figure 3As shown in , in this embodiment, the monitoring assembly 118 includes: a first sensing layer 136 disposed on the second major surface 34 of the porous separator 16; a first buffer layer 138 disposed on the second major surface 34 of the porous separator 16 above the first sensing layer 136; a second sensing layer 152 disposed on the second major surface 34 of the porous separator 16 above the first buffer layer 138; a second buffer layer 154 disposed on the second major surface 34 of the porous separator 16 above the second sensing layer 152; and a transformer 142. The first buffer layer 138 electrically isolates the first sensing layer 136 from the second sensing layer 152, and the second buffer layer 154 electrically isolates the second sensing layer 152 from the facing surface 40 of the negative electrode material layer 24. The transformer 142 is physically separated from the first and second sensing layers 136, 152 and physically connected thereto by first and second electrical connectors 144, 156, respectively.

[0092] Figure 3 The monitoring assembly 118 depicted in the figure can be used to detect the formation of lithium dendrites 150 on the facing surface 40 of the negative electrode material layer 24, which have grown through the second buffer layer 154 and penetrated the second sensing layer 152 or the first sensing layer 136. In such a case, the transducer 142 can be in the form of a potential difference sensor, a current sensor, or another type of sensor or actuator whose output signal can be used to diagnose the formation of lithium dendrites 150. The transducer 142 can periodically or continuously transmit the output signal 158 to the external control device 162. The output signal 158 transmitted by the transducer 142 can indicate or represent the measured potential difference between the negative electrode material layer 24 and the first and second sensing layers 136, 152, and / or the output signal 158 transmitted by the transducer 142 can indicate or represent the current flowing through the first and second sensing layers 136, 152. The external control device 162 can be configured to process the output signal 158 transmitted by the converter 142 to diagnose the formation of lithium dendrites 150 and optionally determine the penetration depth of the lithium dendrites 150. The thickness of the first and second sensing layers 136, 152 and / or the first and second buffer layers 138, 154 can be selected to enable the monitoring component 118 to detect the formation of lithium dendrites 150 that have reached a specific predetermined depth in the cover component of the electrochemical cell 10.

[0093] The output signal 158 transmitted by the converter 142 may be in the form of electromagnetic radiation (e.g., radio waves) or an electrical signal. When the lithium dendrite 150 first penetrates the second sensing layer 152, the output signal 158 transmitted by the converter 142 may be interpreted by the external control device 162 to positively diagnose the formation of the lithium dendrite 150. In addition, the output signal 158 transmitted by the converter 142 may indicate that the lithium dendrite 150 has grown to a size sufficient to penetrate the second sensing layer 152 but has not yet penetrated the first sensing layer 136. If the lithium dendrite 150 continues to grow and subsequently penetrates the first sensing layer 136, the output signal 158 transmitted by the converter 142 may be interpreted by the external control device 162 to positively determine that the lithium dendrite 150 has grown to a size sufficient to penetrate both the first and second sensing layers 136, 152. In an embodiment where the external control device 162 is configured to store historical data received from the converter 142 in a memory as a function of time, the external control device 162 may use the historical data to determine the growth rate of the lithium dendrite 150. In this manner, the monitoring component 118 can track the gradual growth of the lithium dendrites 150 as a function of time.

[0094] In an embodiment, the external control device 162 can be configured to receive data from other components of the electrochemical cell 10 (e.g., from the positive and negative electrodes 12, 14 and / or the external circuit 30). The external control device 162 can receive data related to various operating conditions of the electrochemical cell 10 (e.g., current, cell voltage, and / or individual potentials of the positive and negative electrode material layers 20, 24) from such components, and can store the data as a function of time in a memory. In such a case, the external control device 162 can use the historical data stored in the memory to determine the growth rate and track the growth of the lithium dendrite 150 based on the current, charge rate, cell voltage, and / or potential of the positive and negative electrode material layers 20, 24.

[0095] Figure 4 Another embodiment of a monitoring assembly 218 is depicted that can be used to diagnose and / or monitor an electrochemical cell of a secondary lithium ion or lithium metal battery (such as Figure 1 The monitoring component 218 is similar in many respects to the Figure 1 and Figure 3 The monitoring components 18, 118 shown in the figure are depicted, and the description of common themes will generally not be repeated here. Figure 4As shown in , in this embodiment, the monitoring assembly 218 includes: a sensing layer 236 disposed on the second major surface 34 of the porous separator 16; a buffer layer 238 disposed on the second major surface 34 of the porous separator 16 above the second sensing layer 236; and a transducer 242 integrated into the physical structure of the sensing layer 236. The monitoring assembly 318 can be configured to obtain identification information about the electrochemical cell 10 and / or can be configured to diagnose a specific condition occurring within the electrochemical cell 10. The monitoring assembly 318 can be configured to diagnose a volume change of one or more components of the electrochemical cell 10 (e.g., the porous separator 16 and / or the negative electrode material layer 24), which can change the shape of the sensing layer 236, for example.

[0096] The transducer 242 can be a passive transducer or sensor that can be configured to generate an output signal 258 in response to an excitation signal 260 from an external control device 262. The excitation signal 260 transmitted by the external control device 262 can be in the form of electromagnetic radiation (e.g., radio waves), or the excitation signal 260 can be in the form of an electric current (not shown) passing through the sensing layer 236. The output signal 258 transmitted by the transducer 242 can be in the form of electromagnetic radiation (e.g., radio waves), an electric current, or an electric or magnetic field. Examples of passive transducers include antennas, capacitors, and inductors. The transducer 242 can be integrated into the sensing layer 236 by patterning the conductive material of the sensing layer 236 into the shape of an antenna, a capacitor, or an inductor. The external control device 262 can process the output signal 258 generated by the transducer 242, for example according to instructions stored in a memory, in order to verify the identity of the electrochemical cell 10 of which the sensing layer 236 is a part, or to diagnose a particular condition within the electrochemical cell 10, such as by comparing the information represented by the output signal 258 with information stored in a memory of the external control device 262.

[0097] Figure 5 , Figure 6 and Figure 7 Another embodiment of a monitoring assembly 318 is depicted that can be used to diagnose and / or monitor an electrochemical cell of a secondary lithium ion or lithium metal battery (such as Figure 1 The monitoring component 318 is similar in many respects to the Figure 1 , Figure 3 and Figure 4 The monitoring components 18, 118, 218 described in the foregoing description are not repeated herein, and descriptions of common themes are generally not repeated here. Figure 5, in this embodiment, the monitoring assembly 318 includes: a sensing layer 336 disposed on the second major surface 34 of the porous separator 16; a buffer layer 338 disposed on the second major surface 34 of the porous separator 16 above the sensing layer 336; a transducer 342 integrated into the physical structure of the sensing layer 336; and a microcontroller 346. The microcontroller 346 is electrically coupled to a first end of the sensing layer 336 via a first electrical connector 364 and to a second end of the sensing layer 336 via a second electrical connector 366. The sensing layer 336 includes a conductive material in the form of a plurality of discrete conductive particles 368, and the transducer 342 can be defined by the arrangement of the conductive particles 368 in the sensing layer 336. The conductive particles 368 in the sensing layer 336 can be configured to provide a conductive path through the sensing layer 336 and between the first and second ends of the sensing layer 336.

[0098] Figure 5 The monitoring assembly 318 depicted in the figure can be configured to diagnose changes in the volume of the porous separator 16 and / or changes in the volume of the negative electrode material layer 24, for example, by detecting changes in the resistance of the sensing layer 336. When a known voltage is applied across the sensing layer 336, for example, by the microcontroller 346, a current will flow through the sensing layer 336 along a conductive path defined by the conductive particles 368 in the sensing layer 336, and the amount of current flowing through the sensing layer 336 can be measured by the microcontroller 346. The microcontroller 346 can then calculate the resistance of the sensing layer 336 based on instructions stored in the memory according to Ohm's law. The microcontroller 346 can periodically or continuously measure the current flowing through the sensing layer 336, and use such measurements to calculate the resistance of the sensing layer 336.

[0099] Reference now Figure 6 When the volume of the negative electrode material layer 24 expands, a compressive force will be applied to the adjacent sensing layer 336 through the negative electrode material layer 24, which will increase the packing density of the conductive particles 368 in the sensing layer 336, thereby causing the resistance of the sensing layer 336 to decrease. Figure 7 Alternatively, when the volume of the negative electrode material layer 24 shrinks (or the volume of the porous separator 16 expands), the tensile force will be applied to the adjacent sensing layer 336 through the negative electrode material layer 24, which will reduce the packing density of the conductive particles 368 in the sensing layer 336, thereby causing an increase in the resistance of the sensing layer 336. The microcontroller 346 can compare the calculated resistance of the sensing layer 336 with the historical resistance stored in the memory to diagnose the volume change of the porous separator 16 and / or the negative electrode material layer 24.

[0100] These and other benefits will be readily appreciated by those of ordinary skill in the art in view of the foregoing disclosure.

[0101] Although the best mode and some of the other embodiments have been specifically described, there are various alternative designs and embodiments to practice the present teachings defined in the appended claims. Those skilled in the art will recognize that modifications may be made to the disclosed embodiments without departing from the scope of the present disclosure. Moreover, the present concept explicitly includes combinations and sub-combinations of the described elements and features. The specific embodiments and drawings support and describe the present teachings, and the scope of the present teachings is limited only by the claims.

Claims

1. A monitoring assembly for an electrochemical cell of a secondary lithium battery, the assembly comprising: a porous sensing structure disposed between a major surface of the porous separator and a facing surface of the negative electrode layer, the porous sensing structure comprising: a sensing layer disposed on the major surface of the porous separator, the sensing layer comprising a conductive material and configured to respond to an input signal or a physical stimulus, and a buffer layer disposed between the sensing layer and the facing surface of the negative electrode layer, the buffer layer being made of an electrically insulating material that electrically isolates the sensing layer from the facing surface of the negative electrode layer; and a transducer integrated into the physical configuration of the sensing layer and configured to process the response produced by the sensing layer to generate an output signal indicative of a diagnostic condition of the porous separator or the negative electrode layer; A microcontroller configured to process the output signal generated by the transducer into data and store the data as a function of time in a local memory, and to diagnose and / or monitor changes in the physical structure of the porous separator and / or the negative electrode layer over time by calculating the difference between the most recent data received from the transducer and the historical data stored in the memory. 2 . The assembly of claim 1 , wherein the conductive material of the sensing layer comprises particles of at least one of nickel, copper, titanium, silver, gold, or carbon.

3. The component of claim 1, wherein the electrically insulating material of the buffer layer comprises at least one of Al2O3, SiO2, ZrO2, TiO2, ZnO, Ta2O5, La2O5, HfO, lithium lanthanum zirconium oxide, zeolite, polytetrafluoroethylene, aluminum alkoxide, zirconium alkoxide, titanium alkoxide, or diamond-like carbon. 4 . The assembly of claim 1 , wherein the transducer is configured to process the response generated by the sensing layer into an electrical signal, an electromagnetic signal, or a mechanical signal.

5. The assembly of claim 1, wherein the transducer is an antenna or a resonator, and wherein the transducer is integrated into the sensing layer by patterning the conductive material of the sensing layer into the form of the antenna or the resonator.

6. The assembly of claim 1, wherein the transducer is physically separated from the sensing layer and electrically coupled to the sensing layer via an electrical circuit.

7. The assembly of claim 1, wherein the output signal generated by the transducer indicates the formation of lithium dendrites extending from the facing surface of the negative electrode layer and penetrating the sensing layer.

8. The assembly of claim 1, wherein the porous sensing structure comprises: A first sensing layer is disposed on the major surface of the porous separator, a first buffer layer covers the first sensing layer, a second sensing layer covers the first buffer layer, and a second buffer layer covers the second sensing layer on the major surface of the porous separator.

9. A component according to claim 8, wherein the output signal generated by the converter indicates the formation of lithium dendrites extending from the facing surface of the negative electrode layer and penetrating the first sensing layer, and wherein the output signal generated by the converter indicates the growth rate of the lithium dendrites.

10. The assembly of claim 1, wherein the output signal generated by the transducer is indicative of a resistance of the sensing layer.

11. The assembly of claim 10, wherein the output signal generated by the transducer is indicative of a compressive or tensile force applied to the sensing layer resulting in a physical deformation of the sensing layer.

12. The assembly of claim 1, wherein: The transducer is defined by the arrangement of conductive particles in the sensing layer.

13. The assembly of claim 1, wherein the microcontroller is electrically coupled to the sensing layer via an electrical circuit.

14. The assembly of claim 1, wherein: The monitoring assembly is configured to diagnose and determine one or more of: formation of lithium dendrites, penetration depth of lithium dendrites, and volume changes of the porous separator and / or negative electrode layer.

15. An electrochemical cell of a secondary lithium battery, the electrochemical cell comprising: a positive electrode layer electrically coupled to a positive electrode current collector; a negative electrode layer spaced apart from the positive electrode layer and electrically coupled to a negative electrode current collector; a porous separator disposed between the positive electrode layer and the negative electrode layer and having a first major surface and an opposing second major surface, the first major surface of the porous separator facing a facing surface of the negative electrode layer; as well as Monitoring components, including: a porous sensing structure disposed between the first major surface of the porous separator and the facing surface of the negative electrode layer, the porous sensing structure comprising: a sensing layer disposed on the first major surface of the porous separator, the sensing layer comprising a conductive material and configured to respond to an input signal or a physical stimulus, and a buffer layer disposed between the sensing layer and the facing surface of the negative electrode layer, the buffer layer being made of an electrically insulating material that electrically isolates the sensing layer from the facing surface of the negative electrode layer; and a transducer integrated into the physical configuration of the sensing layer and configured to process the response produced by the sensing layer to generate an output signal indicative of a diagnostic condition within the electrochemical cell; A microcontroller configured to process the output signal generated by the transducer into data and store the data as a function of time in a local memory, and to diagnose and / or monitor changes in the physical structure of the porous separator and / or the negative electrode layer over time by calculating the difference between the most recent data received from the transducer and the historical data stored in the memory.

16. The electrochemical cell according to claim 15, wherein The transducer is defined by the arrangement of conductive particles in the sensing layer.

17. An electrochemical cell according to claim 15, wherein a microcontroller is electrically connected to the negative electrode collector via a first electrical connector and is electrically connected to the positive electrode collector via a second electrical connector, and wherein the microcontroller is powered by a potential difference between the negative electrode collector and the positive electrode collector.

18. The electrochemical cell of claim 15, wherein the porous separator and the porous sensing structure are permeated with a non-aqueous liquid electrolyte solution.

19. The electrochemical cell of claim 15, wherein the sensing layer comprises an electrochemically active reference electrode material comprising at least one metal oxide of lithium iron phosphate, lithium titanium oxide, or lithium nickel manganese cobalt oxide.

20. The electrochemical cell of claim 15, wherein the porous separator is made of an ion-conducting polymer material, and wherein the ion-conducting polymer material comprises at least one of polyethylene, polypropylene, polyamide, polytetrafluoroethylene, polyvinylidene fluoride, or polyvinyl chloride.

21. The electrochemical cell of claim 15, wherein the negative electrode layer comprises: At least one of graphite or silicon, or A layer of lithium metal, and wherein the layer of lithium metal comprises greater than 97% lithium by weight.

22. The electrochemical cell of claim 15, wherein: The monitoring assembly is configured to diagnose and determine one or more of: formation of lithium dendrites, penetration depth of lithium dendrites, and volume changes of the porous separator and / or negative electrode layer.

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