System and device comprising a system for detecting a lithium dendrite in a battery cell

Abstract

A system (110) for detecting a lithium dendrite in a battery cell (15), the system (110) comprising: the battery cell (15), which contains: an anode (20); a cathode (30); a conductive pre-warning layer (60) disposed between the anode (20) and the cathode (30) and made of a porous material; and a separation layer (40) disposed between the conductive pre-warning layer (60) and the cathode (30), the separation layer (40) being configured to allow ions to pass through the separation layer (40); and a sensor (80) electrically connected to the anode (20) and the conductive pre-warning layer (60) and monitoring data relating to a voltage potential between the anode (20) and the conductive pre-warning layer (60); and wherein the data is usable to detect a decrease in the voltage potential between the anode (20) and the conductive pre-warning layer (60) and to diagnose the presence of the lithium dendrite, characterized in that the sensor (80) is electrically connected to the anode (20) and the cathode (30) and receives electrical current via these.

Description

INITIATIONThe disclosure generally relates to a system and method for detecting lithium dimers in a battery cell. Such a system having the features of the preamble of claim 1 is known from DE 10 2013 224 294 A1.A battery cell includes an anode, a cathode, a separator, and an electrolyte solution. Lithium ion battery cells generate electrical current through a chemical reaction in which lithium ions migrate from the anode through the electrolyte to the cathode. When the battery cell is recharged, this reaction proceeds in the reverse manner, with lithium ions migrating to the anode. As these lithium ions travel back to the anode, lithium is deposited on the anode. Particularly in the case of rapid charging, this lithium deposition can lead to the formation of lithium diesters on the anode.SUMMARYIt is an object of the invention to improve a system for detecting a lithium dendrite in a battery cell.This object is achieved by a system having the features of claim 1 and by a device having the features of claim 7.A system for detecting a lithium dendrite in a battery cell is provided. The system according to the invention comprises a battery cell having an anode and a cathode. The battery cell also includes a conductive pre-warning layer disposed between the anode and the cathode and made of a porous material. The battery cell further includes a separation layer disposed between the conductive pre-warning layer and the cathode, the separation layer configured to allow ions to pass through the separation layer. The system further includes a sensor electrically connected to the anode and the conductive pre-warning layer and monitoring data related to a voltage potential between the anode and the conductive pre-warning layer. The data is usable to determine a decrease in the voltage potential between the anode and the conductive pre-warning layer and to diagnose the existence of the lithium dendrite.In some embodiments, the conductive pre-warning layer is made of aluminum, nickel, or tin.In some embodiments, the battery cell further includes a porous and non-conductive spacer between the anode and the conductive pre-warning layer.In some embodiments, the porous and non-conductive spacer is made of a ceramic material.According to the invention, the sensor is electrically connected to the anode and the cathode and receives electric current via said anode.In some embodiments, the system further comprises a computerized warning controller programmed to monitor the data regarding the voltage potential between the anode and the pre-warning conductive layer, analyze the data to identify the decrease in the voltage potential between the anode and the pre-warning conductive layer and diagnose the presence of the lithium dendrite, and generate a warning based on the analysis.In some embodiments, the computerized warning controller also includes programming to isolate the battery cell depending on the analysis.According to a further embodiment of the invention, a device having a system for detecting a lithium dendrite in a battery cell is provided. The device according to the invention contains a battery cell which contains an anode and a cathode. The battery cell also includes a conductive pre-warning layer disposed between the anode and the cathode and made of a porous material. The battery cell further includes a separation layer disposed between the conductive pre-warning layer and the cathode, the separation layer configured to allow ions to pass through the separation layer. The apparatus further includes a sensor electrically connected to the anode and the conductive pre-warning layer and monitoring data related to a voltage potential between the anode and the conductive pre-warning layer. The data is usable to determine a decrease in the voltage potential between the anode and the conductive pre-warning layer and to diagnose the existence of the lithium dendrite.In some embodiments, the apparatus further comprises a vehicle, and the battery cell is disposed in the vehicle.In some embodiments, the device further includes a plurality of battery cells and a plurality of sensors. Each of the plurality of sensors is electrically connected to one of the plurality of battery cells. The data is usable to diagnose the presence of lithium dimers in one of the plurality of battery cells.In some embodiments, the conductive pre-warning layer is made of aluminum, nickel, or tin.In some embodiments, the battery cell further includes a porous and non-conductive spacer between the anode and the conductive pre-warning layer.In some embodiments, the porous and non-conductive spacer is made of a ceramic material.In the device according to the invention, the sensor is electrically connected to the anode and the cathode and receives electric current via said anode.In some embodiments, the apparatus further comprises a computerized warning controller operating programming configured to monitor the data relating to the voltage potential between the anode and the pre-warning conductive layer, analyze the data to identify the decrease in the voltage potential between the anode and the pre-warning conductive layer and diagnose the presence of the lithium dendrite, and generate a warning based on the analysis.In some embodiments, the computerized warning controller also includes programming to isolate the battery cell depending on the analysis.According to an alternative embodiment, a method for detecting a lithium dendrite in a battery cell is provided. The method includes operating the battery cell through a charge cycle or a discharge cycle. The battery cell includes an anode, a cathode, and a conductive pre-warning layer disposed between the anode and the cathode and made of a porous material. The battery cell also includes a separator layer disposed between the conductive pre-warning layer and the cathode. The separation layer is configured such that ions can pass through the separation layer. The method further includes using a sensor electrically connected to the anode and the pre-warning conductive layer to monitor data related to a voltage potential between the anode and the pre-warning conductive layer, identifying a decrease in the voltage potential between the anode and the pre-warning conductive layer, and diagnosing the presence of the lithium dendrite based on the identification of the decrease.In some embodiments, the method further comprises providing electrical current to the sensor by electrically connecting the sensor to the anode and the cathode.The above features and advantages, as well as other features and advantages of the present disclosure, will be readily apparent from the following detailed description of the best modes for carrying out the disclosure when taken in conjunction with the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 schematically illustrates an example battery cell with a system for detecting a lithium dendrite in accordance with the present disclosure; FIG. 2 schematically shows, in accordance with the present disclosure, in an enlarged view, the battery cell of FIG. 1 including a relatively small dendrite spanning a portion of the distance between the anode of FIG. 1 and the pre-warning conductive layer of FIG. 1 ; FIG. 3 schematically shows, in accordance with the present disclosure, in an enlarged view, the battery cell of FIG. 1 including a relatively large dendrite spanning the distance between the anode of FIG. 1 and the pre-warning conductive layer of FIG. 1 and creating a conductive path therebetween; FIG. 4 schematically illustrates an example battery cell with an alternative system for detecting a lithium dendrite, wherein a sensor configured to monitor a voltage potential between an anode and a conductive pre-warning layer receives electrical current from the battery cell for operation, in accordance with the present disclosure; FIG. 5 graphically illustrates a voltage potential between the anode of FIG. 1 and the cathode of FIG. 1 over a period of time, and further illustrates a voltage potential between the anode and a pre-warning conductive layer of FIG. 1 over the period of time; FIG. 6 schematically illustrates a device equipped with a plurality of battery cells including the system for detecting a lithium dendritic and a computer-assisted alert controller configured to alert a user of the device, in accordance with the present disclosure; FIG. 7 schematically illustrates an example communication bus configured to enable electronic communication between the electronic components of the apparatus of FIG. 6 according to the present disclosure; and FIG. 8 is a flow diagram illustrating an example method of operating a system for detecting a lithium dendritic according to the present disclosure.DETAILED DESCRIPTIONA lithium ion battery cell may form dimers or deposits of dimers protruding from a surface of an anode of the battery cell. The anode and the dendrimers are electrically conductive. When a dendrite forms an electrical connection between the anode and the cathode of the battery cell, electrical current may flow directly between the anode and the cathode. This state is comparable to a short circuit or a direct, low-resistance connection between a positive pole of the battery cell and a negative pole of the battery cell. Such an electrical connection, which arises as a result of the dendrite, can lead to the battery cell overheating rapidly and no longer functioning.A system and method for detecting a lithium dendrite is provided. A conductive pre-warning layer can be arranged between the anode and the cathode. As a dendrite grows toward the cathode, it comes into contact with the conductive pre-warning layer before it comes into contact with the cathode. When the dendrite contacts the conductive pre-warning layer, the voltage potential between the anode and the conductive pre-warning layer decreases or approaches zero. This electrical connection between the anode and the conductive pre-warning layer may be used to diagnose that the battery cell needs to be deactivated and taken out of use to prevent the dendrite from growing through the conductive pre-warning layer and contacting the cathode.A battery cell includes the anode and the cathode. The battery cell also includes an electrolyte solution and a separator layer between the anode and the cathode. The separator is a permeable membrane that allows ions to pass on its way from the anode to the cathode or from the cathode to the anode. Similarly, the conductive pre-warning layer allows ions to pass through the conductive pre-warning layer. The conductive pre-warning layer may be made of porous conductive material so that the electrolyte solution may flow through the porous material.The anode and the conductive pre-warning layer may be spaced a certain distance apart, the distance being selected such that the battery cell can be operated until a significant dendrite is formed. If the distance were too small, insignificant lithium formation on the anode, which does not risk growing on the cathode and touching it, would trigger a warning. By selecting a minimum distance between the anode and the conductive pre-warning layer, a dendrite which forms and grows toward the cathode can be identified. A porous and non-electrically conductive spacer can be arranged between the anode and the conductive pre-warning layer, wherein the porous and non-electrically conductive spacer is at least as thick as a minimum threshold distance between the anode and the conductive pre-warning layer. The porous and non-electrically conductive spacer allows the electrolyte solution to flow through the spacer. In one embodiment, the porous and non-electrically conductive spacer may be formed from a porous ceramic material.A sensor may be used to monitor the voltage potential between the anode and the conductive pre-warning layer. In one embodiment, the sensor may be an application specific integrated circuit (ASIC).FIG. 1 schematically shows an exemplary battery cell 15 not according to the invention having a system 10 for detecting a lithium dendrite, wherein like reference numerals refer to like features in the different views. The battery cell 15 is shown to include an anode 20, a cathode 30, a separator 40, a conductive pre-warning layer 60, and a porous and electrically non-conductive spacer 70. An area 50 is indicated that includes layers that are flooded with an electrolyte solution and that allow ion transfer between the anode 20 and the cathode 30. The anode 20 is connected to a negative pole 12 of the battery cell 15. The cathode is connected to a positive pole 14 of the battery cell 15.A sensor 80 configured to monitor a voltage potential between the anode 20 and the conductive pre-warning layer 60 is electrically connected to the negative pole 12 and the anode 20 and additionally electrically connected to the conductive pre-warning layer 60 via the electrical connection 16. The sensor 80 may generate a data stream or a plurality of values in a series indicative of the voltage potential between the anode 20 and the conductive pre-warning layer 60. The data or values generated by the sensor 80 may be received and analyzed by a processing device capable of executing programmed code configured to identify a drop or decrease in the voltage potential between the anode 20 and the conductive pre-warning layer 60 and to issue a dendritic warning based on that identification. In the embodiment of FIG. 1, the sensor 80 is powered via the electrical connection 82.The conductive pre-warning layer 60 may be made of a variety of materials. Exemplary materials include aluminum, nickel, and tin.FIG. 2 schematically shows, in an enlarged view, the battery cell 15 of FIG. 1, including a relatively small dendrite 95 spanning a portion of the distance between the anode 20 and the pre-warning conductive layer 60. The battery cell 15 is shown as having the anode 20, cathode 30, separator 40, conductive pre-warning layer 60, and porous and electrically non-conductive spacer 70. The dendrite 95 is shown with a base formed on the anode 20 and with a tip or extension growing toward the cathode 30. The dendrite 95 is located within the porous and non-electrically conductive spacer 70 and does not contact the conductive pre-warning layer 60. Since there is no electrical connection between the anode 20 and the conductive pre-warning layer 60, no drop or a decrease in the voltage potential is detectable in the sensor measurement values which monitor the voltage potential between the anode 20 and the conductive pre-warning layer 60.FIG. 3 schematically shows, in an enlarged view, the battery cell 15 of FIG. 1, including a relatively large dendrite 95' spanning a distance between the anode 20 of FIG. 1 and the pre-warning conductive layer 60 of FIG. 1 and forming a conductive path therebetween. The battery cell 15 is shown as having the anode 20, cathode 30, separator 40, conductive pre-warning layer 60, and porous and electrically non-conductive spacer 70. The dendrite 95' is shown with a base formed on the anode 20 and a tip or extension which grows toward the cathode 30. The dendrite 95' is located within the porous and non-electrically conductive spacer 70 and is in electrical contact with the conductive pre-warning layer 60. electrical current may flow between the anode 20 and the conductive pre-warning layer 60 such that a drop or decrease in voltage potential becomes visible in the sensor readings monitoring a voltage potential between the anode 20 and the conductive pre-warning layer 60.FIG. 4 schematically shows an exemplary battery cell 15 according to the invention having an alternative system 110 for detecting a lithium dendrite, wherein a sensor 80 configured to monitor a voltage potential between an anode and a conductive pre-warning layer is operated by the battery cell 15 with electric current. The battery cell 15 is shown to include an anode 20, a cathode 30, a separator 40, a conductive pre-warning layer 60, and a porous and electrically non-conductive spacer 70. An area 50 is indicated that includes layers that are flooded with an electrolyte solution and that allow ion transfer between the anode 20 and the cathode 30. The anode 20 is connected to a negative pole 112 of the battery cell 15. The cathode is connected to a positive pole 114 of the battery cell 15.A sensor 80 configured to monitor a voltage potential between the anode 20 and the conductive pre-warning layer 60 is electrically connected to the negative terminal 112 and the anode 20 and additionally electrically connected to the conductive pre-warning layer 60 via the electrical connection 116. In addition, the sensor 80 is connected to the negative pole 112 and the positive pole 114 so that an electric current can flow through the sensor 80 and supply the sensor 80 with current for operation.FIG. 5 graphically illustrates a voltage potential between the anode 20 of FIG. 1 and the cathode 30 of FIG. 1 over a period of time, and further illustrates a voltage potential between the anode 20 and the pre-warning conductive layer 60 of FIG. 1 over the period of time. The diagram 400 further includes a vertical axis having a second axis portion 430 that indicates a voltage potential between the anode 20 and the cathode 30 of the battery cell under test. The horizontal axis 410 represents a time period beginning at a start time 412 and ending at an end time 416. A top plot 440 shows the voltage potential of the battery cell under test measured between the anode 20 and the cathode 30. it can be seen that the battery cell cycles through a series of discharge cycles where the voltage potential decreases and charge cycles where the voltage potential increases. A lower diagram 450 shows the voltage potential between the anode 20 and the conductive pre-warning layer 60. The lower diagram 450 shows a constant or nearly constant voltage potential starting from the starting time 412. A time period 414 between the start time 412 and the end time 416 is shown. At time 414, a dendrite grows sufficiently that the dendrite electrically connects the anode 20 to the conductive pre-warning layer 60. At time 414, the voltage potential between the anode 20 and the pre-warning conductive layer 60, represented by the bottom plot 450, begins to decrease or decrease, indicating that the dendrite begins to flow current between the anode 20 and the pre-warning conductive layer 60. Between time 414 and end time 416, the voltage potential represented by lower plot 450 continues to decrease or decrease, indicating continued electrical connection between anode 20 and pre-warning conductive layer 60 and continued growth of the dendrite. It can be appreciated that since the dendrite does not connect the anode 20 and the cathode 30 to each other, the top plot 440 depicts continuous operation of the battery cell over charging and discharging cycles. However, from the data shown in the lower diagram 450, one can clearly determine dendritic growth and an increased probability that the dendritic will eventually grow to electrically connect the anode 20 and the cathode 30.FIG. 6 schematically shows a device 200 equipped with a plurality of battery cells 15 with the lithium-dendritic sensing system 10 and a computer-assisted alert controller 220 configured to alert a user of the device 200. A number of devices 200 use battery cells 15 and may benefit from a system and method for detecting a lithium dendrite. In FIG. 6, the device 200 is designed as a vehicle. The system 10 includes a plurality of battery cells 15 and a plurality of sensors 80, wherein a sensor 80 monitors one of the battery cells 15. The battery cells 15 are shown as being electrically connected to a power supply system 210 that receives electrical power from the battery cells 15 and provides a particular power, e.g., a driving force, to the device 200. The sensors 80 each monitor a voltage potential between an anode and a conductive pre-warning layer of one of the battery cells 15. The computerized warning controller 220 includes programming configured to monitor data from each of the sensors 80 and diagnose a battery cell 15 having a dendritic problem based on monitoring a drop or decrease in voltage potential for the battery cell 15, as disclosed herein. Additionally, a user display device 230 is shown, which may include a computer-aided touch screen display. The user display device 230 may provide information to a user of the device 200, e.g., a warning that one of the battery cells 15 has a dendritic problem, that the battery cell 15 having the dendritic problem has been isolated from operation, and that the user is instructed to request maintenance or stop the device 200.The computerized alert controller 220 may include a processor configured to execute programmed code and operate an operating system. The processor may include a random access memory (RAM) and a storage device such as a hard disk drive. The computerized warning controller 220 may include programming to analyze data from the sensor 80 of FIG. 1, diagnose the presence of a dendrite based on the analyzed data, and programming to take additional action such as warning a user of a dendrite problem, electrically isolate a battery cell diagnosed with a dendrite, shut down a device operated by a battery cell having a diagnosed dendrite problem, and automatically plan a maintenance deadline to replace a battery cell having a dendrite problem.FIG. 7 schematically illustrates an example communication bus 500 configured to enable electronic communication between electronic components of the device 200 of FIG. 6. FIG. 7 shows a plurality of sensors 80, the computerized alert controller 220, and the user display device 230 electronically connected to and transmitting data and computerized commands over the communication bus 500.FIG. 8 is a flow diagram illustrating an example method 300 of operating a system for detecting a lithium dendrite. The method 300 begins at step 302. In step 304, the battery cell undergoes either a charge cycle or a discharge cycle. In step 306, a sensor monitors a voltage potential between an anode of the battery cell and a conductive pre-warning layer of the battery cell. In step 308, a determination is made as to whether the voltage potential indicates a drop or decrease in the voltage potential consistent with a dendrite that establishes a conductive connection between the anode and the conductive pre-warning layer. If the voltage potential indicates the drop or decrease in the voltage potential so that the formation of the dendrite is diagnosed, method 300 proceeds to step 312. If the voltage potential does not indicate the voltage drop indicative of the formation of the dendrite, the method 300 proceeds to step 310. In step 310, it is determined whether the battery cell is to continue to be used in either a charge cycle or a discharge cycle. If the battery cell continues to be used, the method 300 returns to step 304. If the battery cell is not being used further, the method 300 proceeds to step 314 where the method 300 ends. In step 312, a warning is displayed to the user of the battery cell that a dendrite has formed. Step 312 may include additional functions, such as triggering a shutdown of the battery cell or a device using the battery cell, or triggering an audible alarm. After step 312, the method 300 proceeds to step 314 where the method 300 ends. A number of additional or alternative method steps are conceivable, and the disclosure is not intended to be limited to the examples listed here.While the best modes for carrying out the disclosure have been described in detail, those familiar with the art to which this disclosure relates will recognize various alternative designs and embodiments for carrying out the disclosure within the scope of the appended claims.

Claims

A system (110) for detecting a lithium dendrite in a battery cell (15), the system (110) comprising: the battery cell (15) including: an anode (20); a cathode (30); a conductive pre-warning layer (60) disposed between the anode (20) and the cathode (30) and made of a porous material; and a separation layer (40) disposed between the conductive pre-warning layer (60) and the cathode (30), the separation layer (40) configured to allow ions to pass through the separation layer (40); and a sensor (80) electrically connected to the anode (20) and the conductive pre-warning layer (60) and monitoring data related to a voltage potential between the anode (20) and the conductive pre-warning layer (60); and wherein the data is usable to determine a decrease in the voltage potential between the anode (20) and the conductive pre-warning layer (60) and to diagnose the presence of the lithium dendrite, characterized in that the sensor (80) is electrically connected to the anode (20) and the cathode (30) and receives electric current via said anode.The system (110) of claim 1, wherein the conductive pre-warning layer (60) is made of one of aluminum, nickel, and tin.The system (110) of claim 1, wherein the battery cell (15) further comprises a porous and non-conductive spacer (70) between the anode (20) and the conductive pre-warning layer (60).The system (110) of claim 3, wherein the porous and non-conductive spacer (70) is made of a ceramic material.The system (110) of claim 1, further comprising: a computerized warning controller (220) implementing programming configured to: monitor the data regarding the voltage potential between the anode (20) and the pre-warning conductive layer (60); analyze the data to determine the decrease in the voltage potential between the anode (20) and the pre-warning conductive layer (60) and diagnose the existence of the lithium dendrite; and generate a warning depending on the analysis.The system (110) of claim 5, wherein the computerized warning controller (220) further includes programming to isolate the battery cell based on the analysis.An apparatus (200) having a system (110) for detecting a lithium dendrite in a battery cell (15), the apparatus comprising: the battery cell (15) including: an anode (20); a cathode (30); a conductive pre-warning layer (60) disposed between the anode (20) and the cathode (30) and made of a porous material; and a separation layer (40) disposed between the conductive pre-warning layer (60) and the cathode (30), the separation layer (40) configured to allow ions to pass through the separation layer (40); and a sensor (80) electrically connected to the anode (20) and the conductive pre-warning layer (60) and monitoring data related to a voltage potential between the anode (20) and the conductive pre-warning layer (60); and wherein the data is usable to determine a decrease in the voltage potential between the anode (20) and the conductive pre-warning layer (60) and to diagnose the presence of the lithium dendrite, characterized in that the sensor (80) is electrically connected to the anode (20) and the cathode (30) and receives electric current via said anode.The apparatus (200) of claim 7, wherein the apparatus (200) further comprises a vehicle; and wherein the battery cell (15) is disposed within the vehicle.The apparatus (200) of claim 7, further comprising a plurality of battery cells (15); and further comprising a plurality of sensors (80), wherein each of the plurality of sensors (80) is electrically connected to a corresponding one of the plurality of battery cells (15); and wherein the data is usable to diagnose the presence of the lithium dendrite in one of the plurality of battery cells (15).

Images