Sensing battery electrodes

Abstract

An electrode tab is described. The electrode tab comprises a base layer and an outer layer disposed on the base layer. The base layer comprises a sensor.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Patent Application No. 17 / 017,523, filed on September 10, 2020, and further claims priority to U.S. Provisional Patent Application No. 62 / 900,419, filed on September 13, 2019, and U.S. Provisional Patent Application No. 62 / 901,162, filed on September 16, 2019, the entire contents of each of which are incorporated herein by reference. Technical Field

[0003] Embodiments of the present invention relate to batteries. In particular, embodiments of the present invention generally relate to sensors for batteries. Background Art

[0004] Batteries are essential to the operation of many devices including automobiles, medical devices, mobile electronic devices, and more. As devices become more complex, the demands placed on batteries are increasing, and the operating characteristics of batteries are becoming more important. In order to more efficiently deliver power to devices, it is desirable to reduce charging time and increase capacity without damaging the battery or reducing its life. By more accurately monitoring and controlling the operating characteristics of a battery, it is possible to impact the life of the battery and the operation of the devices that rely on it. Summary of the invention

[0005] An electrode tab is described. The electrode tab includes a base layer having an outer layer formed on each side of the base layer. The base layer includes a sensor.

[0006] According to some embodiments, the sensor is a resistance temperature detector.

[0007] According to some embodiments, the sensor comprises an array of resistive temperature detectors.

[0008] According to some embodiments, the array of RTDs includes two or more redundant RTDs placed on electrode tabs.

[0009] According to some embodiments, the sensor is a pressure sensor.

[0010] According to some embodiments, the pressure sensor is a strain gauge.

[0011] According to some embodiments, the pressure sensor is a capacitive sensor.

[0012] According to some embodiments, the sensor is formed onto a surface of the substrate.

[0013] According to some embodiments, the sensor is etched into the surface of the substrate.

[0014] According to some embodiments, the electrode tab includes an outer layer disposed on the base layer. Embodiments include a method for forming a sensor for an electrode tab, the method comprising: forming one or more sensors in a base layer, the one or more sensors configured to be disposed inside a battery.

[0015] According to some embodiments, the method includes forming an outer layer on the base layer, wherein forming the outer layer on the base layer includes depositing the outer layer using a liquid slot die technique.

[0016] According to some embodiments, the base layer is one of copper, nickel-plated copper, and aluminum.

[0017] According to some embodiments, forming 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.

[0018] According to some embodiments, forming the one or more sensors in the base layer includes patterning the base layer using laser ablation.

[0019] Various embodiments include an electrode tab including: an outer layer; a base layer having the outer layer, the outer layer formed on the base layer, the base layer including one or more sensors; and a reference electrode formed on the base layer.

[0020] According to some embodiments, a reference electrode includes a metal base layer and a coating layer formed on the metal base layer.

[0021] According to some embodiments, the coating is manufactured to chemically match the battery electrolyte.

[0022] According to some embodiments, one or more sensors are configured as any one or more of a resistance temperature detector, a thermocouple, a thermopile, and a thermistor.

[0023] Various embodiments include an electrode tab comprising: a battery electrode; and a sensor attached to the battery electrode.

[0024] According to some embodiments, the sensor is structurally attached to a surface of the battery electrode.

[0025] According to some embodiments, the sensor is electrically coupled to the battery electrode by a hot melt tape.

[0026] According to some embodiments, the sensor and the battery electrodes are coplanar.

[0027] Various embodiments include an electrode tab that additionally includes a single or multiple features from the following list: sensor(s), reference electrode(s), heater(s).

[0028] According to some embodiments, the sensor(s) are thin film based devices.

[0029] According to some embodiments, the reference electrode(s) are coplanar with the electrode.

[0030] Various embodiments include an electrode tab including: an outer layer; and a base layer having the outer layer, the outer layer formed on the base layer, the base layer including one or more reference electrodes formed on the base layer.

[0031] According to some embodiments, the reference electrode(s) include a metal base layer and a coating formed on the metal base layer.

[0032] According to some embodiments, the coating is manufactured to chemically match the battery electrolyte.

[0033] Various embodiments include an electrode tab assembly comprised of any combination of sensor(s), reference electrode(s), and / or heating element(s) described herein.

[0034] Other features and advantages of embodiments of the present invention will be apparent from the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Embodiments of the invention are illustrated by way of example and not limitation in the accompanying drawings in which like references indicate similar elements and in which:

[0036] Figure 1 shows a sensing electrode tab according to one embodiment;

[0037] Figure 2 shows a sensing electrode tab according to one embodiment;

[0038] Figure 3 shows a sensing electrode tab according to one embodiment;

[0039] Figure 4 shows a sensing electrode tab according to one embodiment;

[0040] Figure 5 shows a sensing electrode tab attached to one aspect of a battery according to one embodiment;

[0041] Figure 6shows a sensing electrode tab attached to one aspect of a battery according to one embodiment;

[0042] Figure 7 shows a sensing electrode tab according to one embodiment;

[0043] Figure 8 shows a temperature sensor according to one embodiment;

[0044] Fig. 9 shows a sensing electrode tab according to one embodiment;

[0045] Fig.10 shows an assembly process for forming a sensing electrode tab according to one embodiment;

[0046] Fig.11 shows a sensor on a membrane according to one embodiment;

[0047] Fig.12 shows a panel of sensors on membrane according to one embodiment;

[0048] Fig.13 A flow chart showing a method for forming a sensing electrode tab according to one embodiment is shown;

[0049] Fig.14 A substrate for forming a sensing electrode tab according to one embodiment is shown;

[0050] Fig.15 A coated substrate for forming a sensing electrode tab according to one embodiment is shown;

[0051] Fig.16 A patterned substrate for forming a sensing electrode tab according to one embodiment is shown;

[0052] Fig.17 A plated substrate for forming a sensing electrode tab according to one embodiment is shown;

[0053] Fig.18 shows a pattern on a coated substrate for forming a sensing electrode tab according to one embodiment;

[0054] Fig.19 A coated substrate for forming a sensing electrode tab according to one embodiment is shown;

[0055] Fig. 20 A plated substrate for forming a sensing electrode tab according to one embodiment is shown;

[0056] Fig.21 A panelized substrate for forming sensing electrode tabs according to one embodiment is shown;

[0057] Fig. 22 shows a sensing electrode tab according to one embodiment; and

[0058] Fig.23 A panel of sensing electrode tabs according to one embodiment is shown. DETAILED DESCRIPTION

[0059] Sensing electrode tabs and manufacturing methods according to embodiments of the present invention are described. The sensing electrode tabs enable a power management system connected to a battery to obtain sensor information including temperature, voltage, capacitance, etc. Embodiments of the sensing electrode tabs are configured for use with battery types including, but not limited to, cylindrical batteries (e.g., jelly rolls), pouch batteries, and other battery configurations. In various embodiments, the sensing electrode tabs can be inserted into the electrolyte / electrolyte of the battery to provide sensor information at electrode points for battery charging and / or discharging inside the battery. The power management system uses this sensor information to adjust the battery temperature, charging rate, charging time, etc. to improve battery performance.

[0060] Figures 1 to 4 A sensing electrode tab according to one embodiment is shown. 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 that are integrated into a one-piece structure. The sensing electrode tab 101 includes a first outer layer 110 formed on a substrate. The outer layer 110 can be a polymer film. In various embodiments, the outer layer 110 is a dielectric polymer film including a polyimide layer. The outer layer 110 can be formed on a substrate to expose the battery electrode terminal 102, one or more sensor terminals 104, a reference electrode terminal 106, and a battery electrode interface 108. The substrate can be a metal or a dielectric material.

[0061] The battery electrode terminals 102 and the battery electrode interface 108 interface with the battery electrodes. In various embodiments, the battery electrode interface 108 is included inside the assembled battery, while the battery electrode terminals 102 are located outside the battery. Figures 5 and 6 As shown, the battery electrode interface 108 is coupled to the battery copper foil 306 or another component of the battery. One or more sensor terminals 104 are configured to couple one or more sensors 202 included in the electrode tab 101 to a power management system so that sensor information about the battery can be obtained. The reference electrode terminal 106 is configured to couple the reference electrode 302 to a power management system so that sensor information about the battery can be obtained. In various embodiments, the reference electrode 204 is configured to be positioned inside the assembled battery to provide chemical, voltage, and other sensor information.

[0062] According to various embodiments, one or more sensors 202 are formed on a substrate. In various embodiments, one or more sensors 202 are formed on a substrate of the electrode tab 101 using deposition and etching techniques including those known in the art. In various embodiments, one or more sensors 202 are formed on a film separate from the electrode tab 101 and attached to the electrode tab 101. For example, one or more sensors 202 are formed on a film and attached to the electrode tab 101 using a lamination technique or an adhesive. The following Figure 7 and Fig. 9 An embodiment is shown where one or more sensors 202 are formed on a membrane separate from the electrode tab 101 .

[0063] For some embodiments, the sensor 202 is configured as an array of multiple sensors. The sensor 202 is connected to one or more electrical traces and is electrically coupled to one or more sensor terminals 104. The sensor terminals 104 may include electrical contacts, such as but not limited to contact pads, zero insertion force connections, or other types of electrical contacts, to establish electrical communication with another circuit. According to some embodiments, the sensor terminals are configured to extend beyond the outer layer 102 so that the sensor 202 can be electrically communicated with one or more circuits outside the battery. The one or more circuits may include, but are not limited to, control circuits and monitoring circuits. For example, one or more circuits outside the battery may be configured to optimize the performance of the battery.

[0064] The one or more sensors 202 disposed on the substrate of the electrode tab may include, but are not limited to, temperature sensors, strain gauges, and capacitive sensors. The strain gauge is configured to provide internal pressure detection of one or more sections within the battery. For example, one or more strain gauges may be used to determine gas generation within the battery, which may cause battery bulging. These gases are generated due to electrochemical oxidation of the electrolyte. This oxidation typically occurs due to overcharging of the battery due to battery failure or failure of the charging electronics in the device or battery charger. The capacitive sensor is configured to provide internal pressure detection of one or more sections within the battery. As described herein, the capacitive sensor may be used to determine gas generation within the battery.

[0065] Temperature sensors include, but are not limited to, resistance temperature detectors, thermocouples, thermopiles, and thermistors. The temperature sensor is configured to provide temperature information of one or more sections of a battery cell formed within the battery. According to some embodiments, one or more types of sensors are formed into an array so that one or more types of sensors are configured to provide information about different sections of the battery cell that are in contact with or close to the battery cell electrodes. In various embodiments, one or more sensors may be dual or redundant to ensure reliability and increase error detection. One or more sensors may operate independently of an integrated resistor or meter, such as, but not limited to, a Wheatstone bridge circuit sensing resistor. In various embodiments, one or more sensors, such as an RTD, may be configured to be used as a heater to heat one or more regions of the battery to improve battery performance.

[0066] Those skilled in the art will recognize that one or more sensors 202 described herein can be used in a variety of applications, including chemical sensing, biological sensing, fuel cells, energy harvesters, drug delivery devices, microfluidic devices, micromanipulators, microactuators, solar cells, and organic LEDs, LEDs, and other displays. One or more sensors 202 can be specific to a particular battery cell, battery, or battery pack. Including an electrode tab with one or more sensors in the battery cell of each battery in a battery stack can improve the ability to resolve battery stack performance by enabling the acquisition of sensor information indicating the performance of each battery in the battery stack.

[0067] In various embodiments, one or more sensors 202 can be integrated with a reference electrode 302. The reference electrode 302 is configured to be electrically isolated from the battery electrode and / or current collector, and can be manufactured to chemically match the electrolyte included in the battery. In various embodiments, the reference electrode 302 is configured to be exposed on the back side of the electrode tab opposite to the battery electrode interface 108 to prevent the reference electrode from shorting directly to the battery cell. The reference electrode 302 can be exposed by, for example, etching, laser ablation, etc. of the substrate and / or depositing a dielectric layer (e.g., a polyimide layer).

[0068] The reference electrode 302 can be a conductive metal, such as copper, nickel-plated copper, etc. In various embodiments, the reference electrode 302 can be plated with an optional metal and / or metal oxide, such as gold, silver, platinum, iridium, iridium oxide (IrOX), aluminum, etc. The reference electrode can be plated with a lithium metal oxide component (LiMOx), such as lithium cobalt oxide (LiCoO2), lithium iron phosphate (FeLiO4P), etc. The reference electrode 302 can be assembled inside the battery and can be in contact with the electrolyte so that chemical sensor information about the battery cell can be obtained. The chemical sensor information can include the presence and / or characteristics of a film or other substance deposited on the reference that matches the electrolyte component or a substance that can be electrochemically synthesized by the electrolyte. In various embodiments, the reference electrode 302 includes a counter electrode to transfer current to the reference electrode 302 to sense the battery internal resistance and / or impedance.

[0069] Figure 7 A sensing electrode tab according to one embodiment is shown. The sensing electrode tab includes one or more sensors 406 fixed to an electrode 402. Electrode 402 is a thin metal electrode, for example, a nickel or copper electrode. In various embodiments, the copper electrode may be plated with a metal that is less conductive than copper, such as nickel. According to some embodiments, the width of electrode 402 is between 2-10 mm and the thickness is between 50-200 microns (μm). In various embodiments, electrode 402 is 6 mm wide and 80 μm thick. Electrode 402 may include one or more regions for attaching electrode 402 to a battery. In various embodiments, the electrode is attached to the battery by bonding the electrode electrode to a copper foil using heat (e.g., ultrasonic bonding, laser welding, etc.).

[0070] Figure 8 A temperature sensor according to one embodiment is shown. The temperature sensor 406 is configured as a resistive 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 is electrically coupled 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, which can be docked with one or more circuits outside the battery. In various embodiments, the temperature sensor can be a redundant resistive temperature detector (RTD) having two or more RTDs interwoven to maintain equal temperatures. Redundant RTDs can be used to detect errors in the temperature sensor, for example, a disagreement between two RTDs can be interpreted as a sensor failure, and the performance of the battery can be adjusted to avoid temperature-related problems when operating the battery. For example, the charging rate can be reduced.

[0071] The temperature sensor 406 can be structurally attached to the electrode 402 using heat (e.g., ultrasonic bonding, laser welding, etc.). Alternatively, the temperature sensor 406 can also be attached to the electrode 402 using a bonding adhesive. For example, a hot melt film 404 is applied on the bonding surface of the temperature sensor circuit and the electrode.

[0072] like Fig. 9 As shown, the temperature sensor can be a straight sensor 602 having one or more coplanar sensor terminals attached to the ends of the sensor circuit. In order to avoid stacking sensors on the electrodes, thereby minimizing any changes in electrode thickness due to the sensors and / or maximizing the sensor density for panel manufacturing arrangements. In various embodiments, the sensor 406 can be configured to be coplanar with the electrode 402, and / or structurally independent of the electrode 402. The sensor 406 can be cut out from the panel and assembled to the electrode using a hot melt tape. Fig.12 A panel of a sensor according to some embodiments is shown. Optionally, as Fig.11 As shown, the sensor can be a stand-alone sensor device independent of the electrode.

[0073] Fig.10 Shown is the method for forming Figure 7 The process of sensing battery tabs. The electrode 402 can be fed across from the coil in a continuous assembly process. The electrode 402 is cut from the coil and bonded to the first sealing tape 502 using heat. The sensor 406 is then placed on the electrode so that the temperature sensor is above the electrode, and the sensor circuit 504 is attached to the first tape using heat. The second layer of sealing tape 506 is then fixed to the electrode 402 and the sensor circuit 504 using heat (e.g., hot roll pressing). In various embodiments, the first layer of sealing tape and the second layer of sealing tape are 5 millimeters (mm) wide hot melt tapes processed in a continuous roll.

[0074] Figures 13 to 23 Methods of forming the anode tab 702 according to some embodiments of the present disclosure are described. Fig.14 , a roll of substrate 604 is provided. For some embodiments, substrate 604 is a material with a higher conductivity than nickel. For some embodiments, substrate 604 is copper foil. For some embodiments, the copper foil has been chromated to support direct bonding of the polyimide coating. The copper foil may have a thickness of 20-50 μm. For some embodiments, the copper foil may have a thickness of 35 microns.

[0075] Fig.15A dielectric layer, such as a polyimide coating 706, is shown disposed on a substrate 704. For some embodiments, the polyimide coating 706 is disposed only on a separator side 708 of the substrate 704, and not on a foil side 710 of the substrate 704. For some embodiments, the polyimide coating 706 may be applied at a thickness of 5 to 10 μm to minimize the thickness of the anode tab 702. The polyimide coating 706 is applied using techniques including, but not limited to, liquid slot die, roller coating, spray coating, curtain coating, dry film lamination, and screen printing techniques. For 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 and is exposed to ultraviolet (UV) light, developed, and cured.

[0076] Fig.16 A polyimide coating is shown disposed on the separator side 708 of the substrate 704 with a pattern 712 etched thereon. The pattern 712 etched on 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.

[0077] For some embodiments, in order to form pattern 712 on polyimide coating 706, a photoresist layer is formed on 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. The patterned photoresist layer then provides a pattern to polyimide coating 706 during the polyimide removal process (etching), and wet or dry methods can be used. Subsequently, the photoresist layer can be stripped by techniques known in the art. Also a patterning method is to laser ablate unwanted dielectrics.

[0078] Fig.17 A pattern 722 is shown etched on the foil side 724 of the substrate 704. For some embodiments, the anode tab 702 will have a main anode 726, two RTD leads 728, and a reference electrode lead 728 after the pattern 722 is etched thereon.

[0079] For some embodiments, 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 in order to etch the pattern 722 on the foil side 724 of the substrate 704. The resist coating is applied to the substrate 704 using techniques including, but not limited to, liquid slot die, roll coating, spray coating, curtain coating, dry film lamination, and screen printing techniques. Subsequently, the resist coating is exposed to UV light, developed, etched (i.e., etching the substrate 704 in areas not protected by the resist pattern), and stripped using techniques including photolithography and etching techniques known in the art.

[0080] For some embodiments, the method further includes micro-etching the anode tab 702 to remove the chromate treatment. The micro-etching may be performed using an oxidation process or other techniques known in the art.

[0081] Fig.18 A nickel layer 730 is shown disposed on the copper exposed on the foil side 724 of the substrate 702. For some embodiments, the method includes sputtering nickel on the foil side 724. For some embodiments, the nickel layer 730 has a thickness of about 1-5 μm. Preferably, the nickel layer 730 has a thickness of about 2 μm. Sputtering nickel on the foil side 724 can be performed using techniques known in the art.

[0082] Fig.19 The pattern 732 etched in the nickel layer 730 is shown. For some embodiments, in order to etch the pattern 732 on the nickel layer 730, the method further includes applying 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 to the nickel layer 730 using techniques including, but not limited to, liquid slot die, roller coating, spray coating, curtain coating, dry film lamination, and screen printing techniques. Subsequently, the resist coating is exposed to UV light, developed, etched (i.e., the nickel layer 730 is etched in areas not protected by the resist pattern), and stripped using techniques including photolithography and etching techniques known in the art.

[0083] Fig. 20A second dielectric layer, such as a polyimide layer 734, disposed on the foil side 724 is shown, on which a pattern 736 is engraved. For some embodiments, the polyimide coating 734 may be applied at a thickness of 5 to 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 coating, curtain coating, dry film lamination, and screen printing techniques. For 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, and is exposed to UV light, developed, and cured. The pattern 736 etched on the second polyimide coating 734 includes access points to four pins 738 and the main foil attachment surface 740. The pattern 736 may be etched by techniques discussed in the present disclosure or other techniques known in the art.

[0084] Fig.21 A nickel layer 742 is shown plated on the anode tab 702. In some embodiments, the method includes electroplating nickel on both sides (i.e., the foil side and the separator side) of the anode tab 702. For some embodiments, the nickel layer 742 is soft nickel and covers all exposed nickel faces of the anode tab 702. For some embodiments, the nickel layer 742 has a thickness of about 1-5 μm. Preferably, the nickel layer 742 has a thickness of about 2-3 μm. Nickel can be plated on the anode tab 702 without a mask using techniques known in the art.

[0085] Fig. 22 Anode tabs 702 are shown being panelized, automated optical inspection (AOI) inspected, and defect marked. Such steps may be performed using techniques known in the art.

[0086] Further, the method may include selectively applying a reference electrode material 744. For some embodiments, a thin coating of graphite slurry is selectively applied to the exposed reference electrode 746 by inkjetting, spraying, syringe dispensing, stenciling, and other similar techniques known in the art. The method may further include baking the anode tab 702 after selectively applying the reference electrode material 744. The baking may be performed under conditions known in the art.

[0087] Fig.23 The anode tab 702 is shown with a sealant 748 applied on the short axis of the anode tab 702. For some embodiments, the method includes singulating the anode tab 702 and applying the sealant 748 thereon. The sealant 748 can be applied to a first side and a second side of the anode tab 702 along the short axis of the anode tab 702. In some embodiments, the sealant 748 is a heat seal tape. Other sealants known in the art can also be used.

[0088] A similar method for forming the cathode tab can be performed as the method for forming the anode tab 702. Those skilled in the art will readily appreciate that modifications to the cathode tab can be made based on the method for forming the anode tab 702. For example, the thermal resistor will be replaced with a reference electrode, and a different slurry material, such as a lithium oxide material, is applied to the reference electrode. For some embodiments, the base layer of the cathode tab is aluminum.

[0089] Although described with reference to these embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.

Claims

1. An electrode tab, comprising: a substrate including a sensor, a battery electrode terminal, one or more sensor terminals, a reference electrode terminal, and a battery electrode interface integrated into a unitary structure, and An outer layer is disposed on the base layer, the outer layer comprising a polymer film and having access points exposing the battery electrode terminals, the one or more sensor terminals, the reference electrode terminal, and the battery electrode interface.

2. The electrode tab according to claim 1, characterized in that: The sensor is a resistance temperature detector.

3. The electrode tab according to claim 1, characterized in that: The sensor includes an array of resistive temperature detectors.

4. The electrode tab according to claim 3, characterized in that: The array of RTDs includes two or more redundant RTDs placed on the electrode tabs.

5. The electrode tab according to claim 1, characterized in that: The sensor is a pressure sensor.

6. The electrode tab according to claim 5, characterized in that: The pressure sensor is a strain gauge.

7. The electrode tab according to claim 5, characterized in that: The pressure sensor is a capacitive sensor.

8. The electrode tab according to claim 1, characterized in that: The sensor is formed onto the surface of the substrate.

9. The electrode tab according to claim 1, characterized in that: The sensor is etched into the surface of the substrate.

10. The electrode tab according to claim 3, characterized in that: The electrode tab is an anode tab including a reference electrode.

11. The electrode tab according to claim 1, characterized in that: The electrode tab is a cathode tab including a reference electrode.

12. The electrode tab according to claim 1, characterized in that: The sensor includes an array of any one or more of a resistance temperature detector, a thermocouple, a thermopile, and a thermistor.

13. The electrode tab according to claim 8 or 9, characterized in that: The sensor is a patterned layer.

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