Battery electrode with sensor

Abstract

The electrode tab includes a base layer and an outer layer disposed on the base layer, the base layer including a sensor.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the present invention relate to batteries. In particular, embodiments of the present invention generally relate to sensors for batteries. [Background technology]

[0002] Batteries are critical to the operation of many devices including automobiles, medical devices, mobile electronic devices, etc. As these devices become more sophisticated, the demands on the batteries increase and the operating characteristics of the batteries become more important. Summary of the Invention [Problem to be solved by the invention]

[0003] In order to more efficiently power devices, it is desirable to reduce charging times and increase capacity without damaging or shortening the battery's lifespan. More precise detection and control of the operating characteristics of a battery can affect the battery's lifespan and the operation of devices that depend on the battery. [Means for solving the problem]

[0004] The electrode tab is described as comprising a base layer having an outer layer formed on each side of the base layer, the base layer including a sensor. According to some embodiments, the sensor is a resistance temperature detector.

[0005] According to some embodiments, the sensor includes an array of resistance temperature detectors. According to some embodiments, the array of resistance temperature detectors includes two or more redundant resistance temperature detectors disposed on the electrode tabs.

[0006] According to some embodiments, the sensor is a pressure sensor. According to some embodiments, the pressure sensor is a strain gauge. According to some embodiments, the pressure sensor is a capacitive sensor.

[0007] According to some embodiments, the sensor is formed on a surface of the substrate. According to some embodiments, the sensor is etched onto the surface of the base layer. According to some embodiments, the electrode tab includes an outer layer disposed on a base layer. Embodiments include a method of forming a sensor for the electrode tab, the method including forming one or more sensors in the base layer, the one or more sensors configured to be disposed in a battery.

[0008] According to some embodiments, the method includes forming an outer layer on a base layer, and forming the outer layer on the base layer includes depositing the outer layer using a liquid slot die technique.

[0009] According to some embodiments, the base layer is one of copper, nickel-plated copper, and aluminum. According to some embodiments, forming the one or more sensors in the base layer includes depositing a photoresist layer over the base layer, patterning the photoresist layer, and etching the base layer to form the one or more sensors.

[0010] According to some embodiments, forming the one or more sensors in the base layer includes patterning the base layer using laser ablation. An embodiment includes an electrode tab comprising an outer layer and a base layer having an outer layer formed thereon and one or more sensor and reference electrodes formed thereon.

[0011] According to some embodiments, the reference electrode includes a metal base layer and a coating formed on the metal base layer. According to some embodiments, the coating is manufactured to be chemically compatible with the battery electrolyte.

[0012] According to some embodiments, the one or more sensors are configured as one or more of a resistance temperature detector, a thermocouple, a thermopile, and a thermistor. The embodiment includes an electrode tab, the electrode tab comprising a battery electrode and a sensor attached to the battery electrode.

[0013] According to some embodiments, the sensor is structurally attached to a surface of the battery electrode. According to some embodiments, the sensor is electrically coupled to the battery electrodes by hot melt tape.

[0014] According to some embodiments, the sensor and battery electrodes are coplanar. The embodiment includes an electrode tab, which additionally includes any one or more of a sensor, a reference electrode, and a heater.

[0015] According to some embodiments, the sensor is a film-type device. In some embodiments, the reference electrode is coplanar with the electrode. An embodiment includes an electrode tab having an outer layer and a base layer having an outer layer formed thereon and one or more reference electrodes formed on the base layer.

[0016] According to some embodiments, the reference electrode includes a metal base layer and a coating formed on the metal base layer. According to some embodiments, the coating is manufactured to be chemically compatible with the battery electrolyte.

[0017] Embodiments include an electrode tab assembly comprised of any combination of the sensors, reference electrodes, and / or heater elements described herein. Other features and advantages of embodiments of the present invention will be apparent from the accompanying drawings and from the detailed description that follows.

[0018] Embodiments of the present invention are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which: [Brief description of the drawings]

[0019] [Figure 1] 1 illustrates an electrode tab with a sensor according to one embodiment. [Diagram 2] 1 illustrates an electrode tab with a sensor according to one embodiment. [Diagram 3] 1 illustrates an electrode tab with a sensor according to one embodiment. [Figure 4] 1 illustrates an electrode tab with a sensor according to one embodiment. [Diagram 5] 1 illustrates an electrode tab with a sensor attached to an embodiment of a battery, according to one embodiment. [Figure 6] 1 illustrates an electrode tab with a sensor attached to an embodiment of a battery, according to one embodiment. [Figure 7] 1 illustrates an electrode tab with a sensor according to one embodiment. [Figure 8] 1 illustrates a temperature sensor according to an embodiment. [Figure 9] 1 illustrates an electrode tab with a sensor according to one embodiment. [Figure 10] 1 illustrates an assembly process for forming an electrode tab with a sensor, according to one embodiment. [Figure 11] 1 illustrates a sensor on a film, according to one embodiment. [Figure 12] 1 shows a panel of sensors on a film according to one embodiment. [Figure 13] 1 illustrates a flow diagram of a method for forming an electrode tab with a sensor, according to one embodiment. [Figure 14] 1 illustrates a substrate for forming an electrode tab with a sensor, according to one embodiment. [Figure 15] 1 illustrates a coated substrate for forming an electrode tab with a sensor, according to one embodiment. [Figure 16] 1 illustrates a patterned substrate for forming electrode tabs with sensors, according to one embodiment. [Figure 17] 1 illustrates a plating substrate for forming electrode tabs with sensors, according to one embodiment. [Figure 18] 1 illustrates a pattern formed on a coated substrate to form an electrode tab with a sensor, according to one embodiment. [Figure 19] 1 illustrates a coated substrate for forming an electrode tab with a sensor, according to one embodiment. [Figure 20] 1 illustrates a plating substrate for forming electrode tabs with sensors, according to one embodiment. [Figure 21] 1 illustrates a panelized substrate for forming electrode tabs with sensors, according to one embodiment. [Figure 22] 1 illustrates an electrode tab with a sensor, according to one embodiment. [Diagram 23] 1 illustrates a panel of an electrode tab with a sensor, according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Electrode tabs with sensors and methods of manufacture according to embodiments of the present invention are described. The electrode tabs with sensors allow access to sensor information, including temperature, voltage, capacitance, etc., to a power management system connected to a battery. Embodiments of the electrode tabs with sensors are configured for use with battery types including, but not limited to, cylindrical batteries (e.g., jelly roll), pouch type batteries, and other battery configurations. In various embodiments, the electrode tabs with sensors can be inserted into the electrolyte of the battery to provide sensor information about the interior of the battery at the electrode points where the battery is charged and / or discharged. The power management system uses this sensor information to adjust battery temperature, charge rate, charge time, etc., to improve battery performance.

[0021] 1-4 show an electrode tab with a sensor according to one embodiment. The electrode tab 101 includes one or more features such as one or more sensors 202, a reference electrode 204, and a battery electrode interface 206 integrated into a monolithic structure. The electrode tab with sensor 101 includes a first outer layer 110 formed on a substrate. The outer layer 110 may be a polymer film. In various embodiments, the outer layer 110 is a dielectric polymer film including a layer of polyimide. The outer layer 110 may be formed on the substrate to expose the battery electrode terminal 102, the one or more sensor terminals 104, the reference electrode terminal 106, and the battery electrode interface 108. The substrate may be a metal or a dielectric material.

[0022] The battery electrode terminal 102 and the battery electrode interface 108 are connected to the battery electrodes. In various embodiments, the battery electrode interface 108 is included inside the assembled battery and the battery electrode terminal 102 is outside the battery. As shown in FIGS. 5-6, the battery electrode interface 108 is bonded to a copper battery foil 306 or another component of the battery. The one or more sensor terminals 104 are configured to couple the one or more sensors 202 included in the electrode tab 101 to a power management system to allow access to sensor information about the battery. The reference electrode terminal 106 is configured to couple the reference electrode 302 to a power management system to allow access to sensor information about the battery. In various embodiments, the reference electrode 204 is configured to be disposed within the assembled battery to provide chemical, voltage, and other sensor information.

[0023] The one or more sensors 202, according to various embodiments, are formed on a substrate. In various embodiments, the one or more sensors 202 are formed on the substrate of the electrode tab 101 using deposition and etching techniques, including those known in the art. In various embodiments, the one or more sensors 202 are formed on a film that is separated from and secured to the electrode tab 101. For example, the one or more sensors 202 are formed on a film and secured to the electrode tab 101 using lamination techniques or adhesives. Figures 7 and 9 below show embodiments having the one or more sensors 202 formed on a film that is separated from the electrode tab 101.

[0024] In some embodiments, the sensor 202 is configured as an array of sensors. The sensor 202 is connected to one or more electrical traces and electrically coupled to one or more sensor terminals 104. The sensor terminals 104 can include, but are not limited to, electrical contacts such as contact pads, zero insertion force connections, or other styles for electrical communication with other circuits. According to some embodiments, the sensor terminals are configured to extend beyond the outer layer 102, such that the sensor 202 can be in electrical communication with one or more circuits outside of the battery. The one or more circuits can include, but are not limited to, control circuits and monitoring circuits. For example, the one or more circuits outside of the battery can be configured to optimize the performance of the battery.

[0025] The one or more sensors 202 disposed on the substrate of the electrode tab can include, but are not limited to, a temperature sensor, a strain gauge, and a capacitance sensor. The strain gauge is configured to provide internal pressure detection of one or more portions within the battery. For example, the one or more strain gauges can be used to determine gassing in the battery, which can cause the battery to swell. Gas is generated by electrochemical oxidation of the electrolyte. Such oxidation typically occurs due to overcharging of the battery due to a failure of the battery or a failure of the charging electronics in the device or battery charger. The capacitance sensor is configured to provide internal pressure detection of one or more portions within the battery. The capacitance sensor can be used to determine gassing in the battery as described herein.

[0026] The temperature sensors include, but are not limited to, resistance temperature detectors, thermocouples, thermopiles, and thermistors. The temperature sensors are configured to provide temperature information of one or more portions of a battery cell formed in the battery. According to some embodiments, one or more types of sensors are formed in an array such that one or more types of sensors are configured to provide information regarding different portions of the battery cell in contact with or in close proximity to the battery cell electrodes. In various embodiments, one or more sensors may be dual or redundant for reliability and increased error detection. One or more sensors may operate independently from a resistance sensing Wheatstone bridge circuit, for example, but not limited to. In various embodiments, one or more sensors, such as an RTD, may be configured to act as a heater to warm up one or more regions of the battery to improve battery performance.

[0027] One skilled in the art will recognize that the one or more sensors 202 described herein can be used in a variety of applications, including chemical sensing, biometric sensing, fuel cells, energy harvesters, drug delivery devices, microfluidic devices, micromanipulators, microactuators, solar cells, organic LEDs, LEDs, and other displays. The one or more sensors 202 may be specific to a particular battery cell, battery, or battery stack. Including electrode tabs with one or more sensors in the battery cells of each battery in a battery stack can increase the resolution of battery stack performance by allowing access to sensor information indicative of the performance of each cell in the battery stack.

[0028] In various embodiments, one or more of the sensors 202 may be integrated with a reference electrode 302. The reference electrode 302 may be configured to be electrically insulated from the battery electrodes and / or current collectors and may be fabricated to be chemically compatible with the electrolyte included in the battery. In various embodiments, the reference electrode 302 may be configured to be exposed on the backside of the electrode tab opposite the battery electrode interface 108 to prevent the reference electrode from directly shorting to the battery cell. The reference electrode 302 may be exposed by exposure of the substrate and / or deposition of a dielectric layer, e.g., a polyimide layer, for example, by etching, laser ablation, etc.

[0029] The reference electrode may be a conductive metal, such as copper, nickel-plated copper, etc. In various embodiments, the reference electrode 302 may be plated with alternative metal and / or metal oxide materials, such as gold, silver, platinum, iridium, iridium oxide (IrOX), aluminum, etc. The reference electrode may be made of lithium metal oxide compositions (LiMOx), such as lithium cobalt oxide (LiCoO 2 ), lithium iron phosphate (FeLiO 4The reference electrode 302 may be plated with a metal such as copper, nickel, or zinc. The reference electrode 302 may be assembled inside the battery and may be in contact with the electrolyte to allow access to chemical sensor information about the battery cell. The chemical sensor information may include the presence and / or properties of a film or other material deposited on the reference that matches the composition of the electrolyte or a material that may be electrochemically synthesized from the electrolyte. In various embodiments, the reference electrode 302 includes a counter electrode for passing a current through the reference electrode 302 to sense internal battery resistance and / or impedance.

[0030] FIG. 7 illustrates an electrode tab with a sensor according to one embodiment. The electrode tab with a sensor includes one or more sensors 406 secured to an electrode 402. The electrode 402 is a thin metal electrode, such as a nickel or copper electrode. In various embodiments, the copper electrode may be plated with a metal less conductive than copper, such as nickel. In some implementations, the electrode 402 is 2-10 mm wide and 50-200 microns (μm) thick. In various embodiments, the electrode 402 is 6 mm wide and 80 μm thick. The electrode 402 may include one or more areas for attaching the electrode 402 to a battery. In various embodiments, the electrode is secured to the battery by bonding the electrode to a copper foil using heat, such as ultrasonic bonding, laser welding, or the like.

[0031] FIG. 8 illustrates a temperature sensor according to one embodiment. The temperature sensor 406 is configured as a resistance temperature detector electrically coupled to one or more electrical traces. The temperature sensor 406 is configured as a serpentine line disposed on a polymer film. In various embodiments, the serpentine line is electrically coupled to a first electrical trace at a first end of the serpentine line and to a second electrical trace at a second end of the serpentine line. The temperature sensor 406 is connected to one or more sensor terminals 408 that may interface with one or more circuits outside the battery. In various embodiments, the temperature sensor may be an RTD with two or more redundant resistance temperature detectors (RTDs) interwoven with each other to maintain the same temperature. The redundant RTDs may be used to detect errors in the temperature sensor, e.g., a discrepancy between two RTDs may be interpreted as a sensor failure and the performance of the battery may be altered to avoid temperature-dependent issues with the operation of the battery. For example, the charge rate may be reduced.

[0032] The temperature sensor 406 may be structurally attached to the electrode 402 using heat, e.g., ultrasonic bonding, laser welding, etc. Optionally, the temperature sensor 406 may be adhered to the electrode 402 using an adhesive, such as a hot melt film 404 applied to the bonding surfaces of the temperature sensor circuit and the electrode.

[0033] As shown in FIG. 9, the temperature sensor may be a linear sensor 602 with one or more coplanar sensor terminals fixed to the ends of the sensor circuit. Stacking the sensor on the electrode is avoided, thereby minimizing the variation in electrode thickness (and therefore the sensor) and / or maximizing sensor density for a panel manufacturing layout. In various embodiments, the sensor 406 may be configured to be flush with the electrode 402 and / or to be structurally independent from the electrode 402. The sensor 406 may be cut from the panel and assembled to the electrode using hot melt tape. FIG. 12 shows a panel of sensors according to some embodiments. Optionally, the sensor may be a stand-alone sensor device independent of the electrode, as shown in FIG. 11.

[0034] FIG. 10 illustrates a process for forming the sensor-equipped battery tab of FIG. 7. The electrodes 402 may be fed crosswise from a reel in a continuous assembly process. The electrodes 402 are cut from the reel and bonded to a first sealing tape 502 using heat. The sensor 406 is then placed on the electrode such that the temperature sensor is above the electrode, and the sensor circuit 504 is attached to the first tape using heat. A second layer of sealing tape 506 is then secured to the electrodes 402 and sensor circuit 504 using heat, for example, using hot roll lamination. In various embodiments, the first and second layers of sealing tape are 5 millimeter (mm) wide hot melt tapes processed in a continuous roll.

[0035] 13-23 illustrate a method of forming an anode tab 702 according to some embodiments of the present disclosure. Referring to FIG. 14, a roll of substrate 604 is provided. In some embodiments, substrate 604 is a material having a higher electrical conductivity than nickel. In some embodiments, substrate 604 is a copper foil. In some embodiments, the copper foil is chromated to accommodate direct bonding of a polyimide coating. The copper foil can have a thickness of 20-50 μm. In some embodiments, the copper foil can have a thickness of 35 μm.

[0036] FIG. 15 illustrates a dielectric layer, such as a polyimide coating 706, disposed on a substrate 704. In some embodiments, the polyimide coating 706 is disposed only on the separator side 708 of the substrate 704, and not on the foil side 710 of the substrate 704. In some embodiments, to minimize the thickness of the anode tab 702, the polyimide coating 706 can be applied at a thickness of 5-10 μm. The polyimide coating 706 is applied using techniques including, but not limited to, liquid slot die, roller coating, spray, curtain coating, dry film lamination, and screen printing techniques. In some embodiments, the polyimide coating 706 is applied by liquid slot die deposition. According to some embodiments, the polyimide coating 706 is a photoimageable polyimide that is exposed to ultraviolet (UV) light, developed, and cured.

[0037] 16 shows a polyimide coating disposed on the separator side 708 of a substrate 704 with a pattern 712 etched into it. The pattern 712 etched onto the polyimide coating 706 includes access points to a reference electrode terminal 714, an RTD terminal 716, a reference electrode 718, and a main anode terminal 720.

[0038] In some embodiments, a photoresist layer is formed on the polyimide coating 706 to form a pattern 712 on the polyimide coating 706. According to some embodiments, the photoresist layer is exposed using photolithography techniques, including those known in the art, and developed using wet etching techniques, including those known in the art. This patterned photoresist layer then provides a pattern for the polyimide coating 706 during the polyimide removal process (etch), which can use either wet or dry techniques. The photoresist layer may then be stripped by techniques known in the art. Yet another patterning method is laser ablation of unwanted dielectric.

[0039] 17 shows a pattern 722 etched onto the foil side 724 of the substrate 704. In some embodiments, after the pattern 722 is etched, the anode tab 702 has a main anode 726, two RTD leads 728, and a reference electrode lead 728.

[0040] In some embodiments, to etch the pattern 722 on the foil side 724 of the substrate 704, the method further includes coating a resist layer, exposing the resist layer to UV light, developing the resist layer, etching the substrate, and stripping the resist layer. The resist coating is applied onto the substrate 704 using techniques including, but not limited to, liquid slot die, roller coating, spraying, curtain coating, dry film lamination, and screen printing techniques. The resist coating is then exposed to UV light, developed, etched (i.e., in areas not protected by the resist pattern, the substrate 704 is etched), and stripped using photolithography and etching techniques including those known in the art.

[0041] In some embodiments, the method further includes microetching the anode tab 702 to remove the chromate treatment. Microetching can be done using an oxidation process or by other techniques known in the art.

[0042] 18 shows a nickel layer 730 disposed on the exposed copper on the foil side 724 of the substrate 702. In some embodiments, the method includes sputtering nickel onto the foil side 724. In some embodiments, the nickel layer 730 is about 1-5 μm thick. Preferably, the nickel layer 730 is about 2 μm thick. Sputtering the nickel onto the foil side 724 can be performed using techniques known in the art.

[0043] 19 shows a pattern 732 etched into the nickel layer 730. In some embodiments, to etch the pattern 732 on the nickel layer 730, the method further includes coating a resist layer, exposing the resist layer to UV light, developing the resist layer, etching the substrate, and stripping the resist layer. The resist coating is applied onto the nickel layer 730 using techniques including, but not limited to, liquid slot die, roller coating, spraying, curtain coating, dry film lamination, and screen printing techniques. The resist coating is then exposed to UV light, developed, etched (i.e., in areas not protected by the resist pattern, the nickel layer 730 is etched), and stripped using photolithography and etching techniques including those known in the art.

[0044] FIG. 20 shows a second dielectric layer, such as a polyimide layer 734, disposed over the foil side 724 on which the pattern 736 is etched. In some embodiments, the polyimide coating 734 can be applied at a thickness of 5-10 μm to minimize the thickness of the anode tab 702. The second polyimide coating 734 is applied using techniques including, but not limited to, liquid slot die, roller coating, spray, curtain coating, dry film lamination, and screen printing techniques. In some embodiments, the second polyimide coating 46 is applied by a liquid slot die. According to some embodiments, the second polyimide coating 734 is a photoimageable polyimide that is exposed to UV light, developed, and cured. The pattern 736 etched on the second polyimide coating 734 includes access points to four pinouts 738 and a primary foil attachment surface 740. The pattern 736 can be etched by techniques discussed in this disclosure or other techniques known in the art.

[0045] FIG. 21 shows nickel layer 742 electroplated on anode tab 702. In some embodiments, the method includes electroplating nickel on both sides (i.e., the foil side and the separator side) of anode tab 702. In some embodiments, nickel layer 742 is soft nickel and covers all of the exposed nickel surface of anode tab 702. In some embodiments, nickel layer 742 is about 1-5 μm thick. Preferably, nickel layer 742 is about 2-3 μm thick. Electroplating of nickel on anode tab 702 can be done without a mask using techniques well known in the art.

[0046] 22 shows anode tabs 702 that have been panelized, automated optical inspection (AOI) inspected, and defect marked. These steps can be performed using techniques known in the art.

[0047] Further, the method can include selectively applying the reference electrode material 744. In some embodiments, a thin coating of graphite slurry material is selectively applied to the exposed reference electrode 746 by inkjet, jet, syringe dispenser, stencil, and other similar techniques known in the art. Also, the method can further include baking the anode tab 702 after selectively applying the reference electrode material 744. Baking can be performed under conditions known in the art.

[0048] 23 shows the anode tab 702 with a sealant 748 applied along the minor axis of the anode tab 702. In some embodiments, the method includes singulating the anode tab 702 and applying the sealant 748 thereon. The sealant 748 may be applied to a first side and a second side of the anode tab 702 along the minor axis of the anode tab 702. In some embodiments, the sealant 748 is a heat seal tape. Other sealants known in the art may also be used.

[0049] The method for forming the anode tab 702 can be similar to the method for forming the cathode tab. Those skilled in the art will readily understand modifications to form the cathode tab based on the method for forming the anode tab 702. For example, replace the RTD with a reference electrode and apply a different slurry material, such as a lithium oxide material, onto the reference electrode. In some embodiments, the base layer for the cathode tab is aluminum.

[0050] Although described with reference to these embodiments, workers skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and scope of the invention.

Claims

1. a base layer including a sensor, a battery electrode terminal, one or more sensor terminals, a reference electrode terminal, and a battery electrode interface, the base layer having the sensor, the battery electrode terminal, the one or more sensor terminals, the reference electrode terminal, and the battery electrode interface integrated into a monolithic structure; an outer layer formed on the base layer; the outer layer comprises a polymeric film and has a plurality of access points; the plurality of access points expose the battery electrode terminal, the one or more sensor terminals, the reference electrode terminal, and the battery electrode interface; The sensor is a patterned layer on the base layer, an electrode tab.

2. the sensor is a resistance temperature detector; The electrode tab of claim 1 .

3. the sensor comprising an array of resistance temperature detectors; The electrode tab of claim 1 .

4. the array of resistance temperature detectors includes two or more redundant resistance temperature detectors disposed on the electrode tabs; The electrode tab according to claim 3 .

5. The sensor is a pressure sensor. The electrode tab of claim 1 .

6. the pressure sensor is a strain gauge; The electrode tab according to claim 5 .

7. the pressure sensor is a capacitive sensor; The electrode tab according to claim 5 .

8. the electrode tab being an anode tab including a reference electrode; The electrode tab according to claim 3 .

9. the electrode tab being a cathode tab including a reference electrode; The electrode tab of claim 1 .

10. the sensor includes an array of one or more of a resistance temperature detector, a thermocouple, a thermopile, and a thermistor; The electrode tab of claim 1 .

11. A first tape; a battery electrode bonded to the first tape; a sensor attached to the battery electrode by the first tape, the sensor being patterned on a polymer film; a second tape secured to the battery electrode and the sensor; An electrode tab comprising:

12. the sensor is structurally attached to a surface of the battery electrode; The electrode tab of claim 11.

13. the sensor being electrically coupled to the battery electrode by hot melt tape; The electrode tab of claim 11.

14. the sensor and the battery electrodes are coplanar; The electrode tab of claim 11.

15. A coating composition comprising: an outer layer comprising a polymeric film; a base layer having the outer layer formed thereon, the base layer including a sensor patterned within the base layer, a battery electrode terminal, a battery electrode interface, and one or more reference electrodes formed on the base layer, the sensor, the battery electrode terminal, the battery electrode interface, and the reference electrode being integrated into a monolithic structure; Equipped with the one or more reference electrodes include a metal base layer and a coating formed on the metal base layer; An electrode tab, the outer layer having a plurality of access points exposing at least one reference electrode terminal for the one or more reference electrodes.

16. the coating is manufactured to be chemically compatible with the battery electrolyte; The electrode tab of claim 15.

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