System and method for electrolyte quality inspection and monitoring

Abstract

A system for monitoring a quality of an electrolyte of a battery cell includes a reservoir configured to contain the electrolyte, a capacitive sensor disposed in the reservoir, and a control module in communication with the capacitive sensor. The capacitive sensor is configured to sense a capacitance of the electrolyte when contained in the reservoir. The control module is configured to receive a signal from the capacitive sensor indicative of a capacitance of the electrolyte and determine whether the contained electrolyte is contaminated based on the capacitance of the electrolyte and a defined threshold. Other exemplary systems and methods for monitoring the quality of an electrolyte of a battery cell are also disclosed.

Description

[0001] Introduction

[0002] The information provided in this section is for the purpose of presenting the context of the present disclosure generally. From the description of this section, the work of the presently named inventors and aspects that may not constitute prior art at the time of filing should neither be explicitly nor implicitly considered as prior art of the present disclosure.

[0003] The present disclosure relates to the inspection and monitoring of electrolytes for battery cells.

[0004] Vehicles such as electric vehicles (EVs) include a battery system having one or more battery cells to power various aspects of the vehicle. The battery cells include a solid electrolyte or a liquid electrolyte disposed between one or more cathode electrodes and one or more anode electrodes. The battery cells, including their components, can be inspected for use in quality verification measures. This typically occurs at the end of the battery cell production line. Summary of the Invention

[0005] A system for monitoring the quality of an electrolyte of a battery cell includes a reservoir configured to hold the electrolyte, a capacitance sensor disposed in the reservoir, and a control module in communication with the capacitance sensor. The capacitance sensor is configured to sense the capacitance of the electrolyte when contained in the reservoir. The control module is configured to receive a signal from the capacitance sensor indicative of the capacitance of the electrolyte and determine whether the contained electrolyte is contaminated based on the capacitance of the electrolyte and a defined threshold.

[0006] In other features, the defined threshold is a capacitance range, and the control module is configured to determine that the contained electrolyte is contaminated in response to the capacitance of the electrolyte being outside the capacitance range.

[0007] In other features, the system further includes a temperature sensor disposed in the reservoir. The temperature sensor is configured to sense the temperature of the electrolyte when contained in the reservoir. The control module is configured to receive a signal from the temperature sensor indicative of the temperature of the electrolyte and select the defined threshold from a plurality of thresholds based on the temperature of the electrolyte.

[0008] In other features, the capacitance sensor is a first capacitance sensor, and the system further includes a second capacitance sensor disposed in the reservoir and configured to sense the capacitance of the electrolyte.

[0009] Among other features, the control module is configured to receive a signal indicative of the capacitance of the electrolyte from the second capacitance sensor and determine whether the contained electrolyte is contaminated based on the capacitance received from the first capacitance sensor, the capacitance received from the second capacitance sensor, and a defined threshold.

[0010] Among other features, the control module is configured to determine whether the contained electrolyte is contaminated based on a defined threshold and an average value of the capacitance received from the first capacitance sensor and the capacitance received from the second capacitance sensor.

[0011] Among other features, the system further includes an electrolyte position sensor disposed in the reservoir and configured to sense the level of the electrolyte in the reservoir. The control module is configured to receive a signal indicative of the level of the electrolyte in the reservoir from the electrolyte position sensor.

[0012] Among other features, the system further includes a mixing device disposed in the reservoir. The mixing device is configured to stir the electrolyte when the electrolyte is contained in the reservoir.

[0013] Among other features, the system further includes an electrolyte injector in fluid communication with the reservoir. The electrolyte injector is configured to inject the electrolyte into one or more battery cells if the control module determines that the contained electrolyte is not contaminated.

[0014] Among other features, the control module is configured to monitor the capacitance of the electrolyte over a period of time and determine whether the contained electrolyte is contaminated based on the capacitance of the electrolyte over the period of time and a defined threshold.

[0015] Among other features, the capacitance sensor includes two parallel electrodes.

[0016] Among other features, the capacitance sensor includes two coplanar electrodes.

[0017] Among other features, the reservoir is an electrically grounded tank.

[0018] Among other features, the tank is formed of stainless steel.

[0019] A method for monitoring the quality of electrolyte in a reservoir, comprising: containing electrolyte in the reservoir; sensing the capacitance of the electrolyte using a capacitance sensor disposed in the reservoir; and determining whether the contained electrolyte is contaminated based on the capacitance of the electrolyte and a defined threshold.

[0020] Among other features, the defined threshold is a capacitance range, and determining whether the contained electrolyte is contaminated includes determining that the contained electrolyte is contaminated in response to the capacitance of the electrolyte being outside the capacitance range.

[0021] Among other features, the method further includes sensing the temperature of the electrolyte using a temperature sensor disposed in the reservoir and selecting the defined threshold from a plurality of thresholds based on the temperature of the electrolyte.

[0022] Among other features, the capacitance sensor is a first capacitance sensor, the method further includes sensing the capacitance of the electrolyte using a second capacitance sensor disposed in the reservoir, and determining whether the contained electrolyte is contaminated includes determining whether the contained electrolyte is contaminated based on the defined threshold and an average of the capacitance received from the first capacitance sensor and the capacitance received from the second capacitance sensor.

[0023] Among other features, the method further includes sensing the level of the electrolyte in the reservoir using an electrolyte level sensor disposed in the reservoir.

[0024] Among other features, the method further includes agitating the electrolyte in the reservoir using a mixing device.

[0025] Among other features, the method further includes injecting the electrolyte into one or more battery cells if it is determined that the contained electrolyte is not contaminated.

[0026] Other application areas of the present disclosure will become apparent from the detailed description, the claims, and the drawings. The detailed description and specific examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present disclosure should be more fully understood from the detailed description and the drawings, in which:

[0028] Figure 1 is a functional block diagram of an exemplary system in accordance with the present disclosure including a capacitance sensor for monitoring the quality of the electrolyte of a battery cell;

[0029] Figure 2 is a functional block diagram of an exemplary system in accordance with the present disclosure including two capacitance sensors for monitoring the quality of the electrolyte of a battery cell;

[0030] Figure 3 is a functional block diagram of an exemplary system in accordance with the present disclosure including a capacitance sensor and a temperature sensor for monitoring the quality of the electrolyte of a battery cell;

[0031] Figure 4is a functional block diagram of one exemplary system in accordance with the present disclosure that includes a capacitance sensor, a temperature sensor, and an electrolyte position sensor 406 for monitoring the quality of an electrolyte of a battery cell;

[0032] Figures 5 - 6 is a functional block diagram of an exemplary capacitance sensor in accordance with the present disclosure; and

[0033] Figures 7 - 8 is a flowchart of an exemplary process for monitoring the quality of an electrolyte of a battery cell in accordance with the present disclosure.

[0034] In the figures, reference numerals may be reused to identify like and / or identical elements. DETAILED DESCRIPTION

[0035] A battery cell includes an electrolyte disposed between one or more cathode electrodes and one or more anode electrodes. The battery cell can be used in vehicle applications and / or in any other suitable application for powering various aspects thereof. For vehicle applications, increasing the production volume and size of the manufactured vehicle battery cells has driven the need for improved battery cell quality verification measures. In various embodiments, the quality verification of vehicle battery cells can be performed at the end of the battery cell production line, where a significant amount of time and materials have been invested in manufacturing the battery cells, regardless of whether they meet or do not meet industrial standards. For example, the electrolyte used in a battery cell (e.g., for vehicle applications or other suitable applications) can be determined to be problematic and thus fail a quality inspection after the battery cell has been assembled. This results in a significant loss of time and materials.

[0036] The systems and methods in accordance with the present disclosure provide solutions for accurately and effectively inspecting and monitoring the quality of the electrolyte of a battery cell before providing the electrolyte for use in the battery cell. As further explained herein, the systems and methods rely on capacitance measurements of the electrolyte to determine whether the electrolyte is contaminated before the electrolyte is injected or otherwise provided to the battery cell. In doing so, the systems and methods can determine whether the electrolyte is suitable for use early in the battery cell production line (e.g., pass or fail a quality inspection), thereby saving a significant amount of time and materials.

[0037] Now referring to Figure 1 , which shows a block diagram of an exemplary system 100 for inspecting and monitoring the quality of the electrolyte of a battery cell. The inspection and monitoring system 100 and / or any other exemplary systems and methods herein can be used in manufacturing battery cells for vehicle applications and / or for any other suitable application for powering various aspects associated therewith.

[0038] The inspection and monitoring system 100 generally includes a reservoir 102 for containing the electrolyte 104, a capacitance sensor 106, and a control module 108 in communication with the capacitance sensor 106. Additionally, the system 100 may optionally include a mixing device 110, an electrolyte injector 112, and / or an alarm module 114, as Figure 1 shown.

[0039] As Figure 1 shown, the capacitance sensor 106 is typically disposed within the reservoir 102. More specifically, the capacitance sensor 106 may be located inside the reservoir 102 and immersed in the electrolyte 104. In such an example, the capacitance sensor 106 may be attached to the wall of the reservoir 102 (e.g., the inner-facing side) and suspended in a manner that it can be immersed in the electrolyte 104, and so on.

[0040] In Figure 1 the example, the capacitance sensor 106 can be any suitable type of sensing device. For example, the capacitance sensor 106 can have a pair of electrodes (e.g., conductive plates, etc.). In such an example, the electrodes can be platinum plates, each having any suitable surface area (e.g., in the range of about 900 mm 2 to about 1100 mm 2 and any suitable distance therebetween (e.g., in the range of about 2 to about 5 mm). In various embodiments, the electrodes can extend in parallel planes (e.g., facing each other) or a single plane (e.g., coplanar). For example, Figures 5 - 6 depicts examples of capacitance sensors 506, 606 that can be used as the capacitance sensor 106 and / or any other capacitance sensor herein. In Figures 5 - 6 each capacitance sensor 506, 606 is disposed in a reservoir (e.g., Figure 1 the reservoir 102) having an electrolyte (e.g., the electrolyte 104). In such an example, Figure 5 the capacitance sensor 506 includes two parallel electrodes 530, 532 immersed in the electrolyte 104. Figure 6 the capacitance sensor 606 includes two coplanar electrodes 630, 632 that are immersed in the electrolyte 104 and attached to the wall 634 of the reservoir 102.

[0041] Returning to Figure 1 , the capacitance sensor 106 senses the capacitance of the electrolyte 104. For example, the capacitance sensor 106 receives an alternating voltage signal 116 having a certain frequency and then senses the capacitance of the electrolyte 104. In such an example, the alternating voltage signal 116 can be provided by Figure 1Provided by the control module 108 shown, or from an AC power supply controlled by the control module 108. The frequency can be any suitable value, depending on, for example, the electrolyte 104 and possible contaminants therein. For example, the frequency can be large (e.g., about 2.4 MHz, etc.) or small (e.g., about 1 kHz, etc.) to better amplify the capacitance differences in different electrolytes. In such an example, the optimal frequency for detecting the Li+ concentration in an electrolyte (e.g., a chloride solution) can be about 2.4 MHz. In other examples, the optimal frequency for detecting possible contaminants such as water (H20) and / or hydrogen fluoride (HF) can be about 1 kHz.

[0042] Continuing to refer Figure 1 , the reservoir 102 can be any suitable device for receiving and containing the electrolyte 104. For example, as Figure 1 shown, the reservoir 102 can be a tank that is electrically grounded for shielding. In such an example, the reservoir 102 can include a wire extending therefrom that is electrically connected to the ground. Additionally, the reservoir 102 can also be formed of any suitable material, such as stainless steel, etc.

[0043] In various embodiments, the reservoir 102 (more generally, the system 100) can be part of or associated with a battery cell manufacturing process. In such an example, the system 100 effectively meets the requirements of the battery cell production line, such that the electrolyte 104 flows through the reservoir 102 for inspection purposes before it may be injected into one or more battery cells 118, as further explained herein. For example, as Figure 1 shown, the electrolyte 104 is typically input into the reservoir 102 (e.g., contained therein) and output from the reservoir 102, as shown by the dashed arrows 120, 122. This flow can be achieved by one or more pumps, gravity, etc.

[0044] Figure 1 The mixing device 110 of Figure 1The bottom shown in [figure reference], the middle part near the liquid reservoir 102, etc. The mixing device 110 can be any suitable device for stirring the electrolyte 104 in the liquid reservoir 102 (e.g., a screw conveyor, movable blades, etc.). With this configuration, the electrolyte 104 in the liquid reservoir 102 can be mixed to ensure that the mixture is substantially uniform. In other words, the mixing device 110 ensures that the electrolyte substance near the bottom of the liquid reservoir 102 is substantially the same as the electrolyte substance near the top of the liquid reservoir 102. In such an example, the mixing device 110 can operate continuously or (e.g., through the control module 108) be controlled to operate intermittently.

[0045] Continuing to refer to Figure 1 , the control module 108 is generally configured to inspect and monitor the quality of the electrolyte 104 in the downstream battery cells. For example, after a sufficient amount of electrolyte 104 (or another batch of electrolyte) is contained in the liquid reservoir 102, the control module 108 can receive a signal 124 from the capacitance sensor 106 indicating the capacitance of the electrolyte 104.

[0046] Then, the control module 108 determines whether the contained electrolyte 104 is contaminated based on the capacitance of the electrolyte 104 and a defined threshold. For example, the control module 108 can compare the capacitance of the electrolyte 104 with the defined threshold to determine whether the electrolyte 104 is completely contaminated and fails the quality inspection, or is not completely contaminated and passes the quality inspection. In such an example, the capacitance of the electrolyte 104 varies due to the materials contained therein.

[0047] For example, different materials generally have different dielectric constants, which indicate the degree to which they can store charge. For example, the dielectric constant of water is 78.39, while that of hydrogen fluoride is 84. Since the permittivity of a material is based on its dielectric constant, the permittivity of one material may be different from that of another material. For example, the dielectric constant (k) of a material is the ratio of its permittivity (ε) to the permittivity of vacuum (ε0), as shown in the following equation (1). The capacitance (C) of a material (e.g., the electrolyte 104) can be determined based on the permittivity (ε) of the material, the area (A) of the electrodes, and the distance (d) between the two electrodes, as shown in the following equation (2). Thus, if the area (A) of the electrodes and the distance (d) between the two electrodes are constant, then the capacitance (C) and the permittivity (or dielectric constant) are directly related. Thus, when the capacitance changes due to the dielectric constant of other materials, the sensed capacitance can then be used to determine whether the electrolyte 104 is contaminated by one or more other materials (e.g., H20, HF, etc.).

[0048] Equation (1)

[0049] Equation (2)

[0050] In various embodiments, the defined threshold may be a capacitance range. For example, the defined threshold may be a range that varies from an expected value by a certain amount (e.g., percentage error). For example, the defined threshold may be a range that adds or subtracts a defined amount (e.g., 0.02 μF, 0.03 μF, 0.04 μF, 0.05 μF, 0.06 μF, etc.) from an expected value (e.g., 2.90 μF, 2.91 μF, 2.94 μF, 2.96 μF, 2.97 μF, 2.98 μF, etc.). In such an example, the control module 108 may determine that the electrolyte 104 is contaminated based on the capacitance of the electrolyte 104 being outside the capacitance range. Alternatively, the control module 108 may also determine that the electrolyte 104 is not contaminated based on the capacitance of the electrolyte 104 being within (or meeting) the capacitance range.

[0051] Tests have shown that even trace amounts of contaminants can be detected based on capacitance measurements. By way of example only, a capacitance sensor (e.g., Figure 5 capacitance sensor 506, etc.) may include two parallel electrodes, each of which may have an area (A) of 20 mm 2 and a distance (d) of 8 mm therebetween. In this example, the capacitance sensor is immersed in an electrolyte of ethylene carbonate (EC) with 1 M lithium hexafluorophosphate (LiPF6): dimethyl carbonate (DMC) 3:7 (by volume) + 1 wt% lithium difluoro(oxalate)borate (LiDFOB). Although a specific example provides a specific volume ratio of EC:DMC and a specific weight percentage of LiDFOB, it should be understood that these parameters can all be modified as needed.

[0052] The capacitance measurement of this electrolyte (e.g., fresh electrolyte) may be approximately 2.96 μF. This capacitance may fall within the defined threshold range or otherwise meet the defined threshold (e.g., baseline or established capacitance value) of a specific electrolyte composition, enabling the electrolyte to pass a quality inspection. However, when trace amounts of water (e.g., 1000 ppm, 0.1%) are introduced into the electrolyte, the capacitance measurement increases to approximately 3.039 μF. Additionally, when a salt concentration (e.g., 1.5 M) is introduced into the electrolyte, the capacitance measurement decreases to approximately 2.575 μF. These increased and decreased capacitances may fall outside the defined threshold range or may not meet the defined threshold of a specific electrolyte composition, preventing the electrolyte from passing a quality inspection.

[0053] In various embodiments, the sensitivity of capacitance measurement can be increased. For example, to increase the sensitivity at a lower water level (e.g., about 100 ppm), electrodes with a larger area (A) and a shorter distance (d) therebetween can be employed in a capacitance sensor. An exemplary area (A) can be 1,000 mm 2 , and an exemplary distance (d) can be 2 mm.

[0054] Continuing to refer Figure 1 , the electrolyte injector 112 is in fluid communication with the reservoir 102. In this example, the electrolyte injector 112 can inject the electrolyte 104 into the battery cell(s) 118, as indicated by the dashed arrow 128. This flow can be achieved by one or more pumps, gravity, etc.

[0055] For example, if the control module 108 determines, based on the capacitance measurement from the capacitance sensor 106 and a defined threshold, that the contained electrolyte 104 (or another batch of electrolyte) is not contaminated (e.g., the electrolyte 104 has passed a quality inspection), then the electrolyte injector 112 can inject the electrolyte 104 into the battery cell 118. In various embodiments, the control module 108 can provide a signal 126 to the electrolyte injector 112 to activate a pump, open a valve, etc., to cause the electrolyte 104 to flow to the battery cell(s) 118. However, if the control module 108 determines, based on the capacitance measurement from the capacitance sensor 106 and a defined threshold, that the contained electrolyte 104 is contaminated (e.g., the electrolyte 104 fails the quality inspection), then the delivery of the contaminated electrolyte to the battery cell 118 by the electrolyte injector 112 can be prevented (e.g., via the signal 126) and / or the contaminated electrolyte can be drained from the reservoir 102.

[0056] In various embodiments, the capacitance of the electrolyte 104 can be monitored over a period of time. In such an example, the capacitance can be monitored continuously, periodically, or randomly over that period. For example, the control module 108 can receive capacitance measurements from the capacitance sensor 106. In some examples, the control module 108 can plot a graph of the capacitance of the electrolyte 104 over time and monitor any trends in the distribution of the capacitance. For example, the capacitance of the electrolyte 104 can change and eventually fall within a defined threshold range or otherwise meet the defined threshold for a particular electrolyte composition. In other examples, the capacitance of the electrolyte 104 may tend to deviate from the defined threshold. In such an example, the electrolyte 104 can be discarded, replaced, etc.

[0057] In some examples, the alarm module 114 can communicate with the control module 108, as Figure 1As shown. In such an example, the control module 108 may send a signal 130 to the alarm module 114. In various embodiments, the signal 130 may indicate that the electrolyte 104 has passed or failed a quality inspection, that the electrolyte 104 needs to be further analyzed, etc. Once the signal 130 is received, the alarm module 114 may provide one or more visual alarms (e.g., on a display of the alarm module 114), audible alarms (e.g., from a speaker of the alarm module 114), etc., to indicate that the electrolyte 104 has passed or failed a quality inspection and / or whether further analysis is needed.

[0058] In various embodiments, the system 100 and / or other systems herein may employ multiple capacitance sensors for determining whether the electrolyte is contaminated before the electrolyte is injected or otherwise provided to the battery cell. For example, Figure 2 depicts a system 200 that is substantially similar to Figure 1 system 100 but includes two capacitance sensors. Although Figure 2 the exemplary system 200 is shown as including two capacitance sensors, it should be understood that in other embodiments, the system 200 may include three or more capacitance sensors if desired.

[0059] As Figure 2 shown, the system 200 generally includes a reservoir 102 for containing the electrolyte 104, capacitance sensors 106, a control module 108, a mixing device 110, and Figure 1 an electrolyte injector 112, as well as a capacitance sensor 206. Figure 2 The capacitance sensor 206 of Figure 1 may be similar to or different from the capacitance sensor 106 of

[0060] In Figure 2 the example of Figure 2 shown, the capacitance sensor 206 is disposed in the reservoir 102 and immersed in the electrolyte 104 for sensing the capacitance of the electrolyte 104. In various embodiments, the capacitance sensor 206 may be located near or far from the capacitance sensor 106 as

[0061] shown. For example, the capacitance sensors 106, 206 may be located on opposite sides of the reservoir 102, at the top and bottom of the reservoir 102, etc. Figure 2As shown, the control module 108 can receive signals from the capacitance sensors 106, 206 indicating different capacitance measurements of the electrolyte 104. Then, the control module 108 can determine whether the electrolyte 104 is contaminated based on the capacitance received from the capacitance sensor 106, the capacitance received from the capacitance sensor 206, and a defined threshold value.

[0062] In some examples, the control module 108 can calculate the statistical relationship of different capacitance measurements of the electrolyte 104. For example, the control module 108 can determine the average value of the capacitance received from the capacitance sensor 106 and the capacitance received from the capacitance sensor 206. Then, as described above, the control module 108 can determine whether the electrolyte 104 is contaminated based on the average capacitance of the electrolyte 104 and the defined threshold value.

[0063] In various embodiments, the system 100 and / or other systems herein may also employ different types of sensors in addition to one or more capacitance sensors to determine whether the electrolyte is contaminated before the electrolyte is injected or otherwise provided to the battery cell. For example, Figure 3 depicts a system 300 that is substantially similar to Figure 1 the system 100 but includes a temperature sensor. More specifically, the system 300 generally includes Figure 1 the reservoir 102 for containing the electrolyte 104, the capacitance sensors 106, the control module 108, the mixing device 110, and the electrolyte injector 112 in

[0064] In Figure 3 the example, the temperature sensor 306 is disposed in the reservoir 102 and immersed in the electrolyte 104 to sense the temperature of the electrolyte 104. In various embodiments, the temperature sensor 306 can be located adjacent to or away from the capacitance sensor 106 as Figure 3 shown. For example, the capacitance sensor 106 and the temperature sensor 306 can be located on opposite sides of the reservoir 102, at the top and bottom of the reservoir 102, etc.

[0065] In various embodiments, the control module 108 may determine whether the electrolyte 104 is contaminated based on the temperature of the electrolyte 104. For example, the dielectric constant of a material such as the electrolyte 104 is temperature-dependent. Thus, when the temperature of the electrolyte 104 changes, the dielectric constant of the electrolyte 104 changes, which in turn causes a change in capacitance as described above. In various embodiments, the dielectric constant of a material is inversely proportional to the temperature of the material. Thus, in order to ensure a comparable baseline comparison regarding the sensed capacitance from the capacitance sensor 106, it may be beneficial to generate a defined threshold (e.g., a defined value, a defined range, etc.) based on the temperature of the electrolyte 104 for determining whether the electrolyte 104 is contaminated.

[0066] For example, the control module 108 may receive a signal 324 indicating the temperature of the electrolyte 104 from the temperature sensor 306. Then, based on the sensed or otherwise measured temperature of the electrolyte 104, the control module 108 may determine the defined threshold for determining whether the electrolyte 104 is contaminated. For example, the control module 108 may select the defined threshold (e.g., a defined value, a defined range, etc.) from a plurality of thresholds based on the temperature of the electrolyte 104. In such an example, the available thresholds for selection may be determined based on capacitance testing of the electrolyte (e.g., known to be sufficiently fresh electrolyte) at different temperatures and stored in a memory circuit in or associated with the control module 108.

[0067] In various embodiments, the system 100 and / or other systems herein may employ other different types of sensors in addition to one or more capacitance sensors and / or temperature sensors for determining whether the electrolyte is contaminated before the electrolyte is injected or otherwise provided to the battery cell. For example, Figure 4 depicts a system 400 that is substantially similar to Figure 3 but includes an electrolyte position sensor. More specifically, the system 400 generally includes Figure 1 and 3 the reservoir 102, capacitance sensor 106, temperature sensor 306, control module 108, mixing device 110, and electrolyte injector 112 for containing the electrolyte 104 in

[0068] In Figure 4 the example, the electrolyte position sensor 406 is disposed in the reservoir 102 for sensing the electrolyte 104. The electrolyte position sensor 406 may be any suitable type of device for sensing the level of the electrolyte 104. For example, the electrolyte position sensor 406 may be a level sensor, a float, etc. In various embodiments, as Figure 4As shown, the electrolyte position sensor 406 can be located adjacent to the capacitance sensor 106 and the temperature sensor 306, or at other suitable positions away from the sensors 106, 306. For example, compared with the capacitance sensor 106 and / or the temperature sensor 306, the electrolyte position sensor 406 can be located on the opposite side of the reservoir 102.

[0069] In various embodiments, the control module 108 can determine whether the electrolyte 104 is contaminated based on the characteristics sensed by the electrolyte position sensor 406. For example, the electrolyte position sensor 406 can be used as a height sensor for detecting the level of the electrolyte 104 in the reservoir 102. In such an example, the control module 108 can receive a signal 424 from the electrolyte position sensor 406 indicating the level of the electrolyte 104 in the reservoir 102. In doing so, the control module 108 can monitor the amount of electrolyte in the reservoir 102 to ensure that each measurement from the capacitance sensor 106 is consistent for the same electrolyte batch (e.g., electrolyte 104) and / or from one batch of electrolyte to the next. For example, to ensure consistency in electrolyte testing, it may be desirable to add the same amount of electrolyte to the reservoir 102 so that the area value of the electrodes of the capacitance sensor 106 remains constant in each measurement.

[0070] Figures 7 - 8 Exemplary processes 700, 800 for monitoring the quality of the electrolyte of a battery cell are shown. Although Figures 7 - 8 shown and described as including specific steps, it should be understood that Figures 7 - 8 the processes 700, 800 are merely exemplary variations that can be implemented, and in other embodiments, the processes 700, 800 and / or other exemplary processes can also include different steps, more or fewer steps, etc. Additionally, although the exemplary processes 700, 800 are described with reference to Figures 1 - 4 the systems 100, 200, 300, 400, any one of the processes 700, 800 can also be used by any suitable system.

[0071] As Figure 7 shown, the process 700 begins at 702, where the electrolyte is contained in a reservoir such as Figure 1 the reservoir 102. In such an example, the electrolyte can be provided to the reservoir 102 via one or more pumps, gravity, etc. Then, the process 700 proceeds to 704, where the capacitance of the electrolyte in the reservoir 102 is sensed. In various embodiments, the capacitance of the electrolyte can be sensed by one or more capacitance sensors (such as Figure 1 and 2One or both of the capacitance sensors 106, 206) to sense. In such an example, the capacitance sensor(s) transmits one or more signals to a control module such as Figures 1 - 4 the control module 108.

[0072] At 706, the control module 108 compares the capacitance of the electrolyte with a defined threshold, such as a defined threshold range as explained herein. For example, the control module 108 can compare the capacitance sensed value from one capacitance sensor in the reservoir 102 with the defined threshold. In other examples, the control module 108 can calculate an average capacitance value based on multiple sensed values from the same capacitance sensor or multiple capacitance sensors in the reservoir 102, and then compare the average capacitance value with the defined threshold. Then, process 700 proceeds to 708.

[0073] At 708, the control module 108 determines whether the electrolyte is contaminated based on the capacitance of the electrolyte and the defined threshold. For example, if the capacitance of the electrolyte (e.g., average value or single value) is outside the defined threshold range, the control module 108 can determine that the electrolyte is contaminated, and process 700 proceeds to 714, where a signal indicating that the electrolyte fails the quality inspection is generated. If desired, process 700 can then end. Otherwise, if the capacitance of the electrolyte is within the defined threshold range, the control module 108 can determine that the electrolyte is not contaminated, and process 700 proceeds to 710, where a signal indicating that the electrolyte has passed the quality inspection is generated. Then, process 700 proceeds to 712.

[0074] At 712, the electrolyte is injected into one or more battery cells such as Figures 1 - 4 the battery cell 118. In various embodiments, the control module 108 can provide a signal to an electrolyte injector (such as Figure 1 the electrolyte injector 112) to activate a pump, open a valve, etc., so that the electrolyte 104 can flow to the battery cell 118. If desired, process 700 can then end.

[0075] Figure 8 The exemplary process 800 is similar to Figure 7 the process 700, but has additional and / or alternative steps. For example, process 800 begins with steps 702, 704 as explained above with reference to Figure 7 the process 700. Then, the process proceeds to 806, where the temperature of the electrolyte in the reservoir 102 is sensed. In various embodiments, the temperature of the electrolyte can be sensed by such as Figure 3 and 4is sensed by the temperature sensor 306 of the temperature sensor. In such an example, the temperature sensor 306 transmits one or more signals to the control module 108. The process 800 then proceeds to 808.

[0076] At 808, the control module 108 selects or otherwise determines a defined threshold (e.g., a defined value, a defined range, etc.) from a plurality of thresholds based on the temperature of the electrolyte 104. For example, the plurality of thresholds can be selected via a memory circuit in or associated with the control module 108. In such examples, the plurality of thresholds can be determined based on capacitance tests of the electrolyte (e.g., known properly fresh electrolyte) at different temperatures. Then, the process 800 proceeds to 706, 708 as explained above with reference to Figure 7 the process 700.

[0077] For example, at 708, the control module 108 determines whether the capacitance of the electrolyte is within a selected threshold range. If yes at 708, then Figure 8 the process 800 proceeds to 710, 712, where a signal is generated indicating that the electrolyte has passed a quality check and the electrolyte is injected into one or more of the battery cells 118 of the battery cell such as explained above with reference to Figure 7 the process 700. Then the process 800 proceeds to 818. If no at 708, then Figure 8 the process 800 proceeds to 810.

[0078] At 810, as explained herein, the capacitance of the electrolyte in the reservoir 102 is sensed one or more additional times. In various embodiments, the capacitance of the electrolyte can be sensed continuously, periodically, or randomly over a period of time. In other examples, the capacitance of the electrolyte can be sensed a defined number of times. In any case, the capacitance of the electrolyte can be sensed by the same capacitance sensor used for the initial capacitance sensing in step 704 and / or a different capacitance sensor disposed in the reservoir 102. Figure 8 the process 800 then proceeds to 812.

[0079] At 812, the control module 108 monitors the trend of the capacitance over time. For example, the control module 108 can receive a plurality of capacitance measurements and plot a graph of the electrolyte capacitance over time and monitor any distribution trend of the capacitance. In such an example, the capacitance of the electrolyte can change and ultimately fall within the selected threshold range or otherwise meet the defined threshold for a particular electrolyte composition. In other examples, the capacitance of the electrolyte may tend to move away from the selected threshold. Then, Figure 8 the process 800 proceeds to 814.

[0080] At 814, the control module 108 determines the situation in the electrolyte. The control module 108 determines whether the capacitance of the electrolyte has changed over time and now falls within a selected threshold range. If yes at 814, then Figure 8 process 800 proceeds to 710 as described above. However, if the capacitance of the electrolyte remains outside the selected threshold range, then Figure 8 process 800 proceeds to 714, where a signal is generated indicating that the electrolyte has failed the quality check as described above. Then, process 800 proceeds to 816, where the electrolyte can be discarded, replaced, or otherwise disposed of. Once disposed of, process 800 proceeds to 818, where the next batch of electrolyte is received in reservoir 102 and / or a new can of electrolyte is provided for testing. Then, process 800 returns to 704, as Figure 8 shown.

[0081] Some aspects explained above are summarized by numbered examples below.

[0082] Example 1. A system for monitoring the quality of an electrolyte of a battery cell, the system comprising:

[0083] a reservoir configured to hold the electrolyte;

[0084] a capacitance sensor disposed in the reservoir and configured to sense the capacitance of the electrolyte when held in the reservoir; and

[0085] a control module in communication with the capacitance sensor, the control module being configured to:

[0086] receive a signal indicative of the capacitance of the electrolyte from the capacitance sensor; and determine whether the held electrolyte is contaminated based on the capacitance of the electrolyte and a defined threshold.

[0087] Example 2. The system according to Example 1, wherein:

[0088] the defined threshold is a capacitance range; and

[0089] the control module is configured to determine that the held electrolyte is contaminated in response to the capacitance of the electrolyte being outside the capacitance range.

[0090] Example 3. The system according to Example 1, further comprising a temperature sensor disposed in the reservoir and configured to sense the temperature of the electrolyte when the electrolyte is held in the reservoir, wherein the control module is configured to receive a signal indicative of the temperature of the electrolyte from the temperature sensor and select the defined threshold from a plurality of thresholds based on the temperature of the electrolyte.

[0091] Example 4. The system according to Example 3, wherein:

[0092] the capacitive sensor is a first capacitive sensor;

[0093] the system further includes a second capacitive sensor disposed in the reservoir and configured to sense the capacitance of the electrolyte; and

[0094] the control module is configured to receive a signal indicating the capacitance of the electrolyte from the second capacitive sensor, and determine whether the accommodated electrolyte is contaminated based on the capacitance received from the first capacitive sensor, the capacitance received from the second capacitive sensor, and a defined threshold.

[0095] Example 5. The system according to Example 4, wherein the control module is configured to determine whether the accommodated electrolyte is contaminated based on the defined threshold and the average value of the capacitance received from the first capacitive sensor and the capacitance received from the second capacitive sensor.

[0096] Example 6. The system according to Example 1, further includes an electrolyte level sensor disposed in the reservoir and configured to sense the electrolyte in the reservoir, wherein the control module is configured to receive a signal indicating the level of the electrolyte in the reservoir from the electrolyte level sensor.

[0097] Example 7. The system according to Example 1, further includes a mixing device disposed in the reservoir, the mixing device being configured to stir the electrolyte when the electrolyte is accommodated in the reservoir.

[0098] Example 8. The system according to Example 1, further includes an electrolyte injector in fluid communication with the reservoir, the electrolyte injector being configured to inject the electrolyte into one or more battery cells if the control module determines that the accommodated electrolyte is not contaminated.

[0099] Example 9. The system according to Example 1, wherein the control module is configured to monitor the capacitance of the electrolyte over a period of time and determine whether the accommodated electrolyte is contaminated based on the capacitance of the electrolyte over the period of time and the defined threshold.

[0100] Example 10. The system according to Example 1, wherein the capacitive sensor includes two parallel electrodes.

[0101] Example 11. The system according to Example 1, wherein the capacitive sensor includes two coplanar electrodes.

[0102] Example 12. The system according to Example 1, wherein the reservoir is an electrically grounded tank.

[0103] Example 13. The system according to Example 12, wherein the tank is formed of stainless steel.

[0104] Example 14. A method for monitoring the quality of electrolyte in a reservoir, the method comprising:

[0105] accommodating electrolyte in the reservoir;

[0106] sensing the capacitance of the electrolyte by using a capacitance sensor disposed in the reservoir; and

[0107] determining whether the accommodated electrolyte is contaminated based on the capacitance of the electrolyte and a defined threshold.

[0108] Example 15. The method according to Example 14, wherein:

[0109] the defined threshold is a capacitance range; and

[0110] determining whether the accommodated electrolyte is contaminated includes determining that the accommodated electrolyte is contaminated in response to the capacitance of the electrolyte being outside the capacitance range.

[0111] Example 16. The method according to Example 14, further comprising:

[0112] sensing the temperature of the electrolyte by using a temperature sensor disposed in the reservoir; and

[0113] selecting the defined threshold from a plurality of thresholds based on the temperature of the electrolyte.

[0114] Example 17. The method according to Example 16, wherein:

[0115] the capacitance sensor is a first capacitance sensor;

[0116] the method further comprises sensing the capacitance of the electrolyte by using a second capacitance sensor disposed in the reservoir; and

[0117] determining whether the accommodated electrolyte is contaminated includes determining whether the accommodated electrolyte is contaminated based on the defined threshold and an average value of the capacitance received from the first capacitance sensor and the capacitance received from the second capacitance sensor.

[0118] Example 18. The method according to Example 16, further comprising sensing the liquid level of the electrolyte in the reservoir by using an electrolyte position sensor disposed in the reservoir.

[0119] Example 19. The method according to Example 16, further comprising agitating the electrolyte in the reservoir by using a mixing device.

[0120] Example 20. The method according to Example 16 further includes injecting the electrolyte into one or more battery cells if it is determined that the accommodated electrolyte is not contaminated.

[0121] The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Thus, while the disclosure includes specific examples, the true scope of the disclosure should not be so limited since other modifications will become apparent after study of the drawings, the specification, and the appended claims. It should be understood that one or more steps in a method can be performed in a different order (or concurrently) without altering the principles of the disclosure. Further, although each of the embodiments above is described as having certain features, any one or more of those features described with reference to any embodiment of the invention can be implemented in and / or combined with the features of any one of the other embodiments, even if not explicitly described as such. In other words, the described embodiments are not mutually exclusive, and permutations of one or more of the embodiments with each other remain within the scope of the disclosure.

[0122] Spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including "connected," "engaged," "coupled," "adjacent," "next to," "on top," "above," "below," and "disposed." Unless explicitly described as "direct," when the relationship between a first and a second element is described in the foregoing disclosure, the relationship can be a direct relationship where no other intermediate elements exist between the first and second elements, but can also be an indirect relationship where one or more intermediate elements exist between the first and second elements (spatially or functionally). As used herein, the phrase "at least one of A, B, and C" should be interpreted to mean a logical "or" (A or B or C) using a non-exclusive logic and should not be interpreted to mean "at least one of A, at least one of B, and at least one of C."

[0123] In the drawings, the direction of an arrow as indicated by the arrow generally represents the flow of information of interest (e.g., data or instructions) being illustrated. For example, when element A and element B exchange various information, but the information transmitted from element A to element B is relevant to the illustration, the arrow can point from element A to element B. This one-way arrow does not imply that no other information is transmitted from element B to element A. Further, for the information sent from element A to element B, element B can also send a request for the information or a receipt confirmation of the information to element A.

[0124] In this application, the following definitions are included. The term "module" or the term "controller" may be replaced by the term "circuit". The term "module" may refer to the following, be part of the following, or include the following: application specific integrated circuit (ASIC); digital, analog, or mixed analog / digital discrete circuit; digital, analog, or mixed analog / digital integrated circuit; combinational logic circuit; field programmable gate array (FPGA); processor circuit (shared, dedicated, or group) that executes code; memory circuit (shared, dedicated, or group) that stores code executed by the processor circuit; other suitable hardware components that provide the function; or a combination of some or all of the above, such as in a system on a chip.

[0125] A module may include one or more interface circuits. In some examples, the interface circuit may include a wired or wireless interface connected to a local area network (LAN), the Internet, a wide area network (WAN), or a combination thereof. The functions of any given module of the present disclosure may be distributed among multiple modules connected via the interface circuit. For example, multiple modules may allow load balancing. In other examples, a server (also referred to as remote or cloud) module may perform some functions on behalf of a client module.

[0126] As used above, the term "code" may include software, firmware, and / or microcode, and may refer to programs, routines, functions, classes, data structures, and / or objects. The term "shared processor circuit" encompasses a single processor circuit that executes some or all of the code from multiple modules. The term "group processor circuit" encompasses a processor circuit that, in combination with additional processor circuits, executes some or all of the code from one or more modules. References to a multi-processor circuit encompass multi-processor circuits on discrete die, multi-processor circuits on a single die, multiple cores of a single processor circuit, multiple threads of a single processor circuit, or a combination of the above. The term "shared memory circuit" encompasses a single memory circuit that stores some or all of the code from multiple modules. The term "group memory circuit" encompasses a memory circuit that, in combination with additional memory, stores some or all of the code from one or more modules.

[0127] The term "memory circuit" is a subset of the term "computer-readable medium". As used herein, the term "computer-readable medium" does not cover transient electrical or electromagnetic signals propagated through a medium such as on a carrier wave. Thus, the term "computer-readable medium" can be considered tangible and non-transitory. Non-limiting examples of non-transitory, tangible computer-readable media are non-volatile memory circuits such as flash memory circuits, erasable programmable read-only memory circuits, or mask read-only memory circuits, volatile memory circuits such as static random access memory circuits or dynamic random access memory circuits, magnetic storage media such as analog or digital tapes or hard disk drives, and optical storage media such as CDs, DVDs, or Blu-ray discs.

[0128] The devices and methods described in this application can be implemented, in part or in whole, by a special-purpose computer created by configuring a general-purpose computer to execute one or more specific functions included in a computer program. The above functional blocks, flowchart components, and other elements serve as software specifications, which can be converted into a computer program by routine work of a skilled technician or programmer.

[0129] A computer program includes processor-executable instructions stored on at least one non-transitory, tangible computer-readable medium. The computer program may also include or rely on stored data. The computer program may include a basic input / output system (BIOS) that interacts with the hardware of the special-purpose computer, device drivers that interact with specific devices of the special-purpose computer, one or more operating systems, user applications, background services, background applications, etc.

[0130] A computer program may include: (i) descriptive text to be parsed, such as HTML (HyperText Markup Language), XML (eXtensible Markup Language), or JSON (JavaScript Object Notation); (ii) assembly code; (iii) object code generated from source code by a compiler; (iv) source code executed by an interpreter; (v) source code compiled and executed by a just-in-time compiler, etc. By way of example, languages from the group including C, C++, C#, Objective C, Swift, Haskell, Go, SQL, R, Lisp, Fortran, Perl, Pascal, Curl, OCaml, HTML5 (HyperText Markup Language, 5th Edition), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Visual Lua, MATLAB, SIMULINK, and Write the source code in the syntax of the language.

Claims

1. A system for monitoring the quality of the electrolyte of a battery cell, the system comprising: A reservoir configured to hold the electrolyte; A capacitance sensor disposed in the reservoir, the capacitance sensor being configured to sense the capacitance of the electrolyte when contained in the reservoir; And A control module in communication with the capacitance sensor, the control module being configured to: Receive a signal from the capacitance sensor indicative of the capacitance of the electrolyte; And Determine whether the contained electrolyte is contaminated based on the capacitance of the electrolyte and a defined threshold.

2. The system according to claim 1, wherein: The defined threshold is a capacitance range; And The control module is configured to determine that the contained electrolyte is contaminated in response to the capacitance of the electrolyte being outside the capacitance range.

3. The system according to claim 1, further comprising a temperature sensor disposed in the reservoir and configured to sense the temperature of the electrolyte when the electrolyte is contained in the reservoir, wherein, The control module is configured to receive a signal from the temperature sensor indicative of the temperature of the electrolyte and select the defined threshold from a plurality of thresholds based on the temperature of the electrolyte.

4. The system according to claim 3, wherein: The capacitance sensor is a first capacitance sensor; The system further comprises a second capacitance sensor disposed in the reservoir and configured to sense the capacitance of the electrolyte; And The control module is configured to receive a signal from the second capacitance sensor indicative of the capacitance of the electrolyte and determine whether the contained electrolyte is contaminated based on the capacitance received from the first capacitance sensor, the capacitance received from the second capacitance sensor, and a defined threshold.

5. The system according to claim 4, wherein The control module is configured to determine whether the contained electrolyte is contaminated based on the defined threshold and the average of the capacitance received from the first capacitance sensor and the capacitance received from the second capacitance sensor.

6. The system according to claim 1, further comprising an electrolyte position sensor disposed in the reservoir and configured to sense the electrolyte in the reservoir, wherein, The control module is configured to receive a signal from the electrolyte level sensor indicative of the level of the electrolyte in the reservoir.

7. The system according to claim 1, further comprising a mixing device disposed in the reservoir, the mixing device being configured to stir the electrolyte when the electrolyte is contained in the reservoir.

8. The system according to claim 1, further comprising an electrolyte injector in fluid communication with the reservoir, the electrolyte injector being configured to inject the electrolyte into one or more battery cells if the control module determines that the contained electrolyte is not contaminated.

9. The system according to claim 1, wherein, The control module is configured to monitor the capacitance of the electrolyte over a period of time and determine whether the contained electrolyte is contaminated based on the capacitance of the electrolyte and the defined threshold during the period.

10. A method for monitoring the quality of the electrolyte in a reservoir, the method comprising: Holding the electrolyte in the reservoir; Sensing the capacitance of the electrolyte using a capacitance sensor disposed in the reservoir; And Determining whether the contained electrolyte is contaminated based on the capacitance of the electrolyte and a defined threshold.

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