Electrochromic indicator of battery health information

Abstract

The present disclosure provides an electrochromic indicator of battery health information. A system includes at least one cell stack including one or more battery cells and an electrochromic indicator associated with the one or more battery cells. A vision system monitors each electrochromic indicator.

Description

Technical Field

[0001] The present disclosure relates generally to a system for monitoring the health of a high voltage battery, and more particularly, to a system for monitoring the health of a battery cell using an electrochromic indicator. Background Art

[0002] Electrified vehicles are a type of vehicle designed to reduce automotive fuel consumption and emissions. Generally, they differ from conventional motor vehicles powered by internal combustion engines in that they are optionally driven by one or more battery-powered electric motors. A high-voltage traction battery pack typically supplies power to the electric motors and other electrical loads in the electrified vehicle. A traction battery pack may include one or more interconnected groups of battery cells. Monitoring systems can be used to monitor the cell characteristics of the traction battery pack. Summary of the Invention

[0003] A system according to an exemplary aspect of the present disclosure includes, among other things, at least one cell stack comprising one or more battery cells; an electrochromic indicator associated with the one or more battery cells; and a vision system monitoring each electrochromic indicator.

[0004] In another non-limiting embodiment of the foregoing system, the electrochromic indicator is associated with each battery cell.

[0005] In a further non-limiting embodiment of any of the foregoing systems, the electrochromic indicator comprises a tungsten oxide material.

[0006] In another non-limiting embodiment of any of the foregoing systems, the electrochromic indicator includes a coating having an electrochromic material applied to a surface of the one or more battery cells.

[0007] In another non-limiting embodiment of any of the foregoing systems, each battery cell is comprised of a pouch material, and wherein the electrochromic indicator comprises an electrochromic material integrated into the pouch material of one or more battery cells.

[0008] In another non-limiting embodiment of any of the foregoing systems, the electrochromic indicator includes an indicator body comprising an electrochromic material having a metal strip connecting terminal tabs associated with one or more battery cells.

[0009] In another non-limiting embodiment of any of the foregoing systems, the electrochromic indicator is comprised of a material that changes color or opacity in response to an electrical stimulus.

[0010] In another non-limiting embodiment of any of the foregoing systems, the one or more battery cells have a predefined voltage range with a minimum voltage and a maximum voltage, and wherein the material changes color when the voltage is at or below the minimum voltage and / or the voltage is at or above the maximum voltage.

[0011] In another non-limiting embodiment of any of the foregoing systems, the material changes to a first color when the voltage of the one or more battery cells is at or below a minimum voltage, and wherein the material changes to a second color when the voltage of the one or more battery cells is at or above a maximum voltage.

[0012] In another non-limiting embodiment of any of the foregoing systems, the voltage of one or more battery cells varies over time, and wherein the color change of the material remains permanent when the voltage is at or below a minimum voltage and / or the voltage is at or above a maximum voltage.

[0013] In another non-limiting embodiment of any of the foregoing systems, the vision system includes one or more cameras, and includes one or more controllers that receive data from the one or more cameras.

[0014] In another non-limiting embodiment of any of the foregoing systems, the one or more controllers are configured to generate a notification when the voltage is at or below a minimum voltage and / or when the voltage is at or above a maximum voltage.

[0015] In another non-limiting embodiment of any of the foregoing systems, the at least one cell stack comprises a plurality of cell stacks for a battery pack, and wherein the electrochromic indicator is permanently associated with the one or more battery cells.

[0016] A method according to an exemplary aspect of the present disclosure includes, among other things, providing at least one cell stack comprising one or more battery cells; associating an electrochromic indicator with the one or more battery cells; and visually monitoring each electrochromic indicator.

[0017] In another non-limiting embodiment of the foregoing method, the method further comprises electrically stimulating the material of the electrochromic indicator and visually monitoring the color change of the material, and wherein the material changes to a first color when the voltage of the one or more battery cells is at or below a minimum voltage, and / or wherein the material changes to a second color when the voltage of the one or more battery cells is at or above a maximum voltage.

[0018] In a further non-limiting embodiment of any of the foregoing methods, the method further includes generating a notification when the voltage is at or below a minimum voltage and / or when the voltage is at or above a maximum voltage.

[0019] In another non-limiting embodiment of any of the foregoing methods, the voltage of one or more battery cells varies over time, and wherein the color change of the material remains permanent when the voltage is at or below a minimum voltage and / or the voltage is at or above a maximum voltage.

[0020] In another non-limiting embodiment of any of the foregoing methods, the method further includes providing a vision system including one or more cameras, and including one or more controllers receiving data from the one or more cameras to identify a color change in the material, and including:

[0021] storing the at least one battery cell stack in a storage facility and visually monitoring the electrochromic indicators of the one or more battery cells with the one or more cameras over time;

[0022] transporting the at least one battery cell stack for assembly into a vehicle and visually monitoring the electrochromic indicators of one or more battery cells with one or more cameras during transport; or

[0023] The at least one cell stack is sent to a testing facility or a recycling facility, and the electrochromic indicator of the one or more battery cells is visually monitored at the testing facility or the recycling facility with one or more cameras.

[0024] In another non-limiting embodiment of any of the foregoing methods, the at least one cell stack includes a plurality of cell stacks for a battery pack, and the method includes permanently associating the electrochromic indicator with each battery cell.

[0025] In a further non-limiting embodiment of any of the foregoing systems, the electrochromic indicator comprises an electrochromic material, and the method comprises:

[0026] applying a coating having the electrochromic material to a surface of the one or more battery cells;

[0027] forming each battery cell from a pouch material and integrating the electrochromic material into the pouch material of the one or more battery cells; or

[0028] An indicator body including the electrochromic material is formed from a metal strip that connects connector terminals associated with the one or more battery cells.

[0029] The embodiments, examples and alternatives of the preceding paragraphs, claims or following description and drawings, including any of their various aspects or corresponding individual features, may be taken independently or in any combination. Features described in conjunction with one embodiment apply to all embodiments, unless such features are incompatible. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] According to the detailed description, various features and advantages of the disclosed examples will become apparent to those skilled in the art. The drawings accompanying the detailed description can be briefly described as follows:

[0031] Figure 1 An electrified vehicle is schematically shown.

[0032] Figure 2 Shown Figure 1 Traction battery packs for electrified vehicles.

[0033] Figure 3 Shown Figure 2 The cell stack of the traction battery pack.

[0034] Figure 4 An example of a health monitoring system is schematically shown.

[0035] Figure 5 Another example of a health monitoring system is schematically shown.

[0036] Figure 6A An example of a battery cell is schematically shown in a first condition.

[0037] Figure 6B An example of a battery cell in a second condition is schematically shown.

[0038] Figure 6C An example of a battery cell in a third condition is schematically shown.

[0039] Figure 7 An example of a battery cell having a coating comprising an electrochromic material is schematically shown.

[0040] Figure 8 One example of an electrochromic indicator attached to a battery cell is schematically shown. DETAILED DESCRIPTION

[0041] This disclosure details a system for monitoring battery health using electrochromic indicators. An exemplary system may include: a battery pack including at least one cell stack comprising one or more battery cells; an electrochromic indicator associated with the one or more battery cells; and a vision system that monitors each electrochromic indicator. These and other features are discussed in greater detail in the following sections of this detailed description.

[0042] Figure 1An electrified vehicle 10 is schematically shown. The electrified vehicle 10 may include any type of electrified powertrain. In an embodiment, the electrified vehicle 10 is a battery electric vehicle (BEV). However, the concepts described herein are not limited to BEVs and may be extended to other electrified vehicles, including but not limited to hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell vehicles, and the like. Thus, although not specifically shown in the exemplary embodiment, the powertrain of the electrified vehicle 10 may be equipped with an internal combustion engine, which may be employed alone or in combination with other power sources to propel the electrified vehicle 10.

[0043] In the illustrated embodiment, the electrified vehicle 10 is depicted as an automobile. However, the electrified vehicle 10 may alternatively be a sport utility vehicle (SUV), a van, a pickup truck, or any other vehicle configuration. Although specific component relationships are shown in the figures of the present disclosure, the illustrations are not intended to limit the present disclosure. The placement and orientation of the various components of the electrified vehicle 10 are shown schematically and may vary within the scope of the present disclosure. In addition, the various figures accompanying the present disclosure are not necessarily drawn to scale, and some features may be exaggerated or minimized to emphasize certain details of a particular component or system.

[0044] In an embodiment, the electrified vehicle 10 is a pure electric vehicle that is propelled solely by electricity, such as by one or more electric machines 12, without any assistance from an internal combustion engine. The electric machines 12 can operate as electric motors, generators, or both. The electric machines 12 receive electrical power and can convert the power into torque for driving one or more wheels 14 of the electrified vehicle 10.

[0045] A voltage bus 16 can electrically couple the electric machine 12 to a traction battery pack 18. The traction battery pack 18 is an exemplary electric vehicle battery. The traction battery pack 18 can be a high-voltage traction battery pack assembly that includes a plurality of battery cell groups capable of outputting electrical power to power the electric machine 12 and / or other electrical loads of the electric vehicle 10. Other types of energy storage devices and / or output devices can alternatively or additionally be used to power the electric vehicle 10.

[0046] The traction battery pack 18 may be secured to an underbody 20 of the electrified vehicle 10. However, the traction battery pack 18 may be located elsewhere on the electrified vehicle 10 within the scope of the present disclosure.

[0047] Figure 2 and Figure 3Additional details associated with the traction battery pack 18 of the electrified vehicle 10 are shown. The traction battery pack 18 may include a plurality of cell stacks 22 housed within an interior area 30 of a housing assembly 24. The housing assembly 24 of the traction battery pack 18 may include a housing cover 26 and a housing tray 28. The housing cover 26 may be secured (e.g., bolted, welded, adhered, etc.) to the housing tray 28 to provide an interior area 30 for housing the cell stacks 22 and other battery internal components of the traction battery pack 18 (e.g., bus bars, control modules and other electronics, etc.). The size, shape, and configuration of the housing assembly 24 may vary within the scope of the present disclosure.

[0048] Each cell stack 22 may include a plurality of individual battery cells 32 (see Figure 3 The battery cells 32 store and supply electricity for powering various components to support electric propulsion of the electrified vehicle 10 .

[0049] In one embodiment, the battery cells 32 are lithium-ion pouch cells. However, within the scope of the present disclosure, battery cells having other geometries (cylindrical, prismatic, etc.) and / or chemistries (nickel-metal hydride, lead acid, etc.) may alternatively be utilized.

[0050] Although a specific number of cell stacks 22 and battery cells 32 are shown in the various figures of this disclosure, the traction battery pack 18 may include any number of cell stacks 22 , with each cell stack 22 having any number of individual battery cells 32 .

[0051] Each battery cell 32 may include a first face 34, a second face 36 opposite the first face 34, a first end 38, a second end 40 opposite the first end 38, a top side 42, and a bottom side 44 opposite the top side 42. The first face 34 and the second face 36 establish major side surfaces of the battery cell 32, and the first end 38, the second end 40, the top side 42, and the bottom side 44 establish minor side surfaces of the battery cell 32. Thus, the first face 34 and the second face 36 present a larger surface area than any of the first end 38, the second end 40, the top side 42, and the bottom side 44.

[0052] The battery cells 32 of each cell stack 22 can be stacked side by side relative to each other along the cell stack axis A (see Figure 3). The battery cells 32 can be arranged so that the faces 34, 36 of one battery cell 32 are in direct contact with one of the faces 34 or 36 of an adjacent battery cell 32 of the battery stack 22. The battery cells 32 can be held in compression relative to each other within the battery stack 22 to provide a face-to-face cell arrangement. For example, the compression can be applied by a support structure (not shown) for the battery stack 22. However, other configurations are contemplated within the scope of the present disclosure. The support structure can include any combination of plates, walls, beams, beams, bindings, and the like.

[0053] The connector terminals 46 may project outwardly from each of the first end 38 and the second end 40 of the battery cells 32. Thus, the battery cells 32 may be considered to be "sideways oriented" within the cell stack 22. The connector terminals 46 may be connected to bus bars (not shown) to electrically connect the battery cells 32 of each cell stack 22.

[0054] Monitoring the state of health of each battery cell 32 is important for detecting operational related issues. For example, a change in voltage can indicate a problem with the associated battery cell 32. When assembling individual battery cells 32 or arrays into a battery pack 18, it is important that all battery cells 32 are at the same open circuit voltage (OCV) / state of charge (SOC) to allow for the most efficient performance of the system. Additionally, monitoring the battery cells 32 between manufacturing, formation, and assembly can reduce costs by preventing substandard cells from entering the battery pack 18. Similarly, at the end of its life, it is difficult to know the history of a battery cell 32, and exposure to high voltage will determine whether the battery cell 32 can be recycled or reused for a second life.

[0055] In one example, the visual monitoring system 60 is used to monitor the health of the battery cells 32, such as Figure 4 In one example, one or more cell stacks 22 include one or more battery cells 32 having electrochromic indicators 62 associated with the one or more battery cells 32 and a vision system 64 that monitors each electrochromic indicator 62. Figure 4 In the example shown in FIG, there are four cell stacks 22, each having fourteen battery cells 32; however, it should be understood that any number of stacks 22 and / or cells 32 may be used.

[0056] In one example, an electrochromic indicator 62 is associated with each battery cell 32 .

[0057] In one example, the electrochromic indicator 62 is composed of a material that changes color or opacity in response to an electrical stimulus. For example, the material may change color due to the application of a voltage. As is well known, voltage (e.g., electromotive force) includes energy per unit charge, that is, voltage is the potential difference between two points. In one example, the material having electrochromic properties is a transition metal oxide, particularly WO3, MoO3, IrO2, NiO, and V2O5. In one example, the electrochromic material includes tungsten oxide WO3.

[0058] Figure 4 An example is shown where a group of cell stacks 22 are stored in a storage facility on shelves or in containers / crates 50. Vision system 64 visually monitors the electrochromic indicator 62 of each battery cell 32 via line of sight 52 to identify any changes in color.

[0059] Figure 5 An example is shown in which the battery cells 32 are transferred for assembly purposes via a conveyor 66. Likewise, the vision system 64 visually monitors the electrochromic indicator 62 of each battery cell 32 via the line of sight 52 to identify any changes in color.

[0060] Figures 6A to 6C An example of a color change associated with a battery cell 32 is shown. Figure 6A An example of a battery cell 32 in a first condition is schematically shown, and Figure 6B An example of a battery cell in a second condition is schematically shown. Figure 6C As shown in FIG, for each battery cell 32, there is a predefined voltage range 68 having a minimum voltage 70 and a maximum voltage 72. In one example, the material changes color when the voltage is at or below the minimum voltage 70 and / or when the voltage is at or above the maximum voltage 72. For example, the predefined voltage range 68 may range between a minimum voltage 70 of 1.2V and a maximum voltage 72 of 4.4V. However, it should be understood that this is merely an example, and other ranges may be used based on the type of application, performance requirements, etc.

[0061] Figure 6A Examples are shown where the battery cells 32 are within the colors of the predefined voltage range 68 . Figure 6B An example is shown in which the battery cells 32 are in a different second color when the voltage of one or more of the battery cells is at or exceeds the maximum voltage 72 . Figure 6C An example is shown where the material changes to a different third color when the voltage of the battery cell 32 is at or below the minimum voltage 70 .

[0062] In one example, the voltage of one or more battery cells 32 changes over time, and the vision system 64 continuously monitors the electrochromic indicator 62 of each battery cell 32 to identify any changes in color. Figure 6C An example is shown in which the color change of the material remains permanent when the voltage is at or below the minimum voltage 70 and / or the voltage is at or above the maximum voltage 72, even though the voltage of the battery cell 32 may return to within the predefined voltage range 68. This may be referred to as a tip indicator 94 because it is a permanent change, while the center electrochromic indicator changes continuously. This allows identification of fluctuations above and below the predefined voltage range 68 that may have compromised the health of the battery cell 32. Thus, any damaged battery cell 32 can be removed and replaced before being assembled into the battery pack 18.

[0063] In one example, the vision system 64 includes one or more cameras 74 and one or more controllers 76 that receive data from the one or more cameras 74. In one example, the one or more controllers 76 are configured to generate a notification signal 78 when the voltage is at or below the minimum voltage 70 and / or when the voltage is at or above the maximum voltage 72. The notification signal 78 can be, for example, an audible noise, a visual signal, or a message automatically transmitted to a person responsible for monitoring the status of the battery cells 32. For example, the message can be transmitted via a visual display or a smart device.

[0064] In one example, the controller 76 may include a processor, memory, and one or more input and / or output (I / O) device interfaces communicatively coupled via a local interface. The local interface may include, for example, but not limited to, one or more buses and / or other wired or wireless connections. Additionally, the controller 76 may be a hardware device for executing software, particularly software stored in the memory. The controller 76 may be a custom or commercially available processor, a central processing unit (CPU), an auxiliary processor of several processors associated with a computing device, a semiconductor-based microprocessor (in the form of a microchip or chipset), or any device generally used to execute software instructions.

[0065] In one example, the memory may include any one or a combination of volatile memory elements (e.g., random access memory (RAM, such as DRAM, SRAM, SDRAM, VRAM, etc.) and / or non-volatile memory elements (e.g., ROM, hard drive, magnetic tape, CD-ROM, etc.). In addition, the memory may incorporate electronic, magnetic, optical and / or other types of storage media. In one example, the software in the memory may include one or more separate programs, each of which includes an ordered list of executable instructions for implementing logical functions. A system component embodied as software may also be interpreted as a source program, an executable program (object code), a script, or any other entity that includes a set of instructions to be executed. The controller 76 may be configured to execute the software stored in the memory to transfer data to and from the memory, and generally control the operation of the computing device according to the software. The software in the memory is read in whole or in part by the processor, possibly buffered within the processor, and then executed.

[0066] In one example, the electrochromic indicator 62 is permanently associated with each battery cell 32. In one example, the location of the electrochromic indicator 62 can be on a side or face of the battery cell 32. Figures 6A to 6C The example of FIG. 1 shows an example of a permanently integrated electrochromic indicator 62. Each battery cell 32 is comprised of a pouch material 80, and in this example, the electrochromic indicator 62 includes an electrochromic material 82 integrated into the pouch material 80 of the battery cell 32. In one example, the electrochromic material 82 is associated with a wire 84 that is electrically connected to the connector terminal 46.

[0067] Figure 7 An example is shown in which the electrochromic indicator 62 includes a coating 86 having an electrochromic material 82 applied to an exterior surface 88 of the battery cell 32 and electrically connected to the connector terminal 46 .

[0068] Figure 8 An example is shown in which the electrochromic indicator 62 includes an indicator body 90 that includes the electrochromic material 82 , with metal strips or wires 92 connecting the connector terminals 46 associated with the battery cells 32 .

[0069] The present disclosure also provides a method comprising providing at least one cell stack 22 including one or more battery cells 32 ; associating an electrochromic indicator 62 with the one or more battery cells 32 ; and visually monitoring each electrochromic indicator 62 .

[0070] The method may also include any of the following steps, alone or in any combination. For example, the method may include electrically stimulating the material 82 of the electrochromic indicator 62 and visually monitoring the color change of the material 82, and wherein the material 82 changes to a first color when the voltage of the one or more battery cells 32 is at or below a minimum voltage, and / or wherein the material 82 changes to a second color when the voltage of the one or more battery cells 32 is at or above a maximum voltage.

[0071] For example, the method may include generating a notification 78 when the voltage is at or below a minimum voltage and / or when the voltage is at or above a maximum voltage.

[0072] For example, the method may include varying the voltage of one or more battery cells 32 over time, and wherein the color change of the material 82 remains permanent when the voltage is at or below a minimum voltage and / or the voltage is at or above a maximum voltage.

[0073] For example, the method may include providing a vision system 64 including one or more cameras 74, and including one or more controllers 76 receiving data from the one or more cameras 74 to identify color changes in the material 82. The method may include:

[0074] storing the at least one battery cell stack 22 in a storage facility and visually monitoring the electrochromic indicators 62 of the one or more battery cells 32 over time with the one or more cameras 74;

[0075] transporting the at least one battery cell stack 22 for assembly into a vehicle and visually monitoring the electrochromic indicators 62 of one or more battery cells with one or more cameras 74 during transport; or

[0076] The at least one cell stack 22 is sent to a testing facility or a recycling facility, and the electrochromic indicators 62 of the one or more battery cells 32 are visually monitored at the testing facility or recycling facility using one or more cameras 74 .

[0077] For example, the method may include permanently associating an electrochromic indicator 62 with each battery cell 32 .

[0078] For example, the method may include applying a coating 86 having an electrochromic material 82 to a surface of one or more battery cells 32 ; forming each battery cell from a soft pack material 80 and integrating the electrochromic material 82 into the soft pack material 80 of one or more battery cells 32 ; or forming an indicator body 90 including the electrochromic material 82 with a metal strip 92 that connects the connector terminals 46 associated with the one or more battery cells 32 .

[0079] The present disclosure uses electrochromic materials on the battery cells 32 or battery stack 22 (e.g., a thin film coating integrated with the soft pack material and formed into the body of the indicator) as a method of monitoring the cells / arrays in conjunction with the vision system 64 during storage, testing, assembly, etc. This eliminates the need for cables and / or sensors to monitor OCV / SOC as with existing systems. If the cell 32 reaches a voltage that is not within the expected range, the tip indicator 94 will turn a specific color indicating that the cell 32 has experienced a voltage outside the specification level. The tip indicator 94 will serve as a quality assurance tool that can be used before the cell 32 is shipped to the OEM, can be used as a check by the OEM before the array or battery pack is assembled, and can be an indicator of the end of the healthy life of the cell. The present disclosure provides an electrochromic indicator 62 paired with a vision system 64 to monitor color changes in the cell 32 to identify any potential problems. The vision system 64 will allow the battery pack / array to be scanned in a more efficient manner rather than inspecting individual cells. As discussed above, the vision system 64 is a computer system that includes one or more cameras 74 and an application or software that captures real-time images of the battery cells 32 in storage and monitors their color status. If a cell's voltage begins to rise or fall, the camera will capture the change in color, and the software will be able to identify the cell and provide a notification signal for an engineer to inspect. If the cells are traveling on a conveyor, the camera 74 can observe the cells 32 as they pass by and indicate if their status is out of bounds. It is also possible to use the vision camera to detect defective cells in storage.

[0080] The foregoing description is illustrative rather than restrictive in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art, and such variations and modifications do not necessarily depart from the essence of the present disclosure. Therefore, the scope of protection afforded to the present disclosure should be determined solely by studying the appended claims.

[0081] According to the present invention, a system is provided having: at least one cell stack, the at least one cell stack including one or more battery cells; an electrochromic indicator associated with the one or more battery cells; and a vision system that monitors each electrochromic indicator.

[0082] According to an embodiment, said electrochromic indicator is associated with each battery cell.

[0083] According to an embodiment, the electrochromic indicator comprises a tungsten oxide material.

[0084] According to an embodiment, the electrochromic indicator comprises a coating comprising an electrochromic material, which coating is applied to a surface of the one or more battery cells.

[0085] According to an embodiment, each battery cell consists of a pouch material, and wherein the electrochromic indicator comprises an electrochromic material integrated into the pouch material of the one or more battery cells.

[0086] According to an embodiment, the electrochromic indicator includes an indicator body comprising an electrochromic material having a metal strip connecting connector terminals associated with the one or more battery cells.

[0087] According to an embodiment, the electrochromic indicator consists of a material that changes color or opacity in response to an electrical stimulus.

[0088] According to an embodiment, the one or more battery cells have a predefined voltage range with a minimum voltage and a maximum voltage, and wherein the material changes color when the voltage is at or below the minimum voltage and / or the voltage is at or above the maximum voltage.

[0089] According to an embodiment, the material changes to a first color when the voltage of the one or more battery cells is at or below the minimum voltage, and wherein the material changes to a second color when the voltage of the one or more battery cells is at or above the maximum voltage.

[0090] According to an embodiment, the voltage of the one or more battery cells varies over time, and wherein the color change of the material remains permanent when the voltage is at or below the minimum voltage and / or the voltage is at or above the maximum voltage.

[0091] According to an embodiment, the vision system includes one or more cameras and includes one or more controllers that receive data from the one or more cameras.

[0092] According to an embodiment, the one or more controllers are configured to generate a notification when the voltage is at or below the minimum voltage and / or when the voltage is at or above the maximum voltage.

[0093] According to an embodiment, the at least one cell stack comprises a plurality of cell stacks for a battery pack, and wherein the electrochromic indicator is permanently associated with the one or more battery cells.

[0094] According to the present invention, a method includes providing at least one cell stack including one or more battery cells; associating an electrochromic indicator with the one or more battery cells; and visually monitoring each electrochromic indicator.

[0095] In one aspect of the invention, the method comprises electrically stimulating a material of an electrochromic indicator and visually monitoring a color change of the material, and wherein the material changes to a first color when the voltage of the one or more battery cells is at or below a minimum voltage, and / or wherein the material changes to a second color when the voltage of the one or more battery cells is at or above a maximum voltage.

[0096] In one aspect of the invention, the method includes generating a notification when the voltage is at or below the minimum voltage and / or when the voltage is at or above the maximum voltage.

[0097] In one aspect of the invention, the voltage of the one or more battery cells varies over time, and wherein the color change of the material remains permanent when the voltage is at or below the minimum voltage and / or the voltage is at or above the maximum voltage.

[0098] In one aspect of the invention, the method includes providing a visual system comprising one or more cameras, and includes one or more controllers receiving data from the one or more cameras to identify color changes in the material, and the method includes: storing the at least one battery cell stack in a storage facility and visually monitoring the electrochromic indicators of the one or more battery cells with the one or more cameras over time; transporting the at least one battery cell stack for assembly into a vehicle and visually monitoring the electrochromic indicators of the one or more battery cells with the one or more cameras during transport; or sending the at least one battery cell stack to a testing facility or a recycling facility and visually monitoring the electrochromic indicators of the one or more battery cells with the one or more cameras at the testing facility or the recycling facility.

[0099] In one aspect of the invention, the at least one cell stack comprises a plurality of cell stacks for a battery pack and includes permanently associating the electrochromic indicator with each battery cell.

[0100] In one aspect of the present invention, the electrochromic indicator includes an electrochromic material and comprises: applying a coating having the electrochromic material to a surface of the one or more battery cells; forming each battery cell from a soft pack material and integrating the electrochromic material into the soft pack material of the one or more battery cells; or forming an indicator body including the electrochromic material with a metal strip connected to connector terminals associated with the one or more battery cells.

Claims

1. A system comprising: at least one battery cell stack, the at least one battery cell stack comprising one or more battery cells; an electrochromic indicator associated with one or more battery cells; as well as A vision system monitors each electrochromic indicator.

2. The system of claim 1 , wherein the electrochromic indicator is associated with each battery cell, and optionally, wherein the at least one cell stack comprises a plurality of cell stacks for a battery pack, and wherein the electrochromic indicator is permanently associated with the one or more battery cells.

3. The system of claim 1, wherein the electrochromic indicator comprises a tungsten oxide material.

4. The system of claim 1, wherein the electrochromic indicator comprises a coating having an electrochromic material, the coating being applied to a surface of the one or more battery cells.

5. The system of claim 1 , wherein each battery cell is comprised of a pouch material, and wherein the electrochromic indicator comprises an electrochromic material integrated into the pouch material of the one or more battery cells.

6. The system of claim 1, wherein the electrochromic indicator comprises an indicator body comprising an electrochromic material having a metal strip connecting connector terminals associated with the one or more battery cells.

7. The system of claim 1, wherein the electrochromic indicator is comprised of a material that changes color or opacity in response to an electrical stimulus.

8. The system of claim 7, wherein the one or more battery cells have a predefined voltage range with a minimum voltage and a maximum voltage, and wherein the material changes color when the voltage is at or below the minimum voltage and / or the voltage is at or above the maximum voltage.

9. The system of claim 8, wherein the material changes to a first color when the voltage of the one or more battery cells is at or below the minimum voltage, and wherein the material changes to a second color when the voltage of the one or more battery cells is at or above the maximum voltage.

10. The system of claim 8, wherein the voltage of the one or more battery cells varies with time, and wherein, The color change of the material remains permanent when the voltage is at or below the minimum voltage and / or the voltage is at or above the maximum voltage.

11. The system of claim 8, wherein the vision system comprises one or more cameras, and comprises one or more controllers to receive data from the one or more cameras, and optionally, wherein the one or more controllers are configured to generate a notification when the voltage is at or below the minimum voltage and / or the voltage is at or above the maximum voltage.

12. A method comprising: providing at least one battery cell stack, the at least one battery cell stack comprising one or more battery cells; associating an electrochromic indicator with one or more battery cells; as well as Each electrochromic indicator was monitored visually.

13. The method of claim 12 , comprising electrically stimulating a material of the electrochromic indicator and visually monitoring a color change of the material, and wherein the material changes to a first color when the voltage of the one or more battery cells is at or below a minimum voltage, and / or wherein the material changes to a second color when the voltage of the one or more battery cells is at or above a maximum voltage; as well as Optionally, wherein the electrochromic indicator comprises an electrochromic material, and the method comprises: applying a coating having the electrochromic material to a surface of the one or more battery cells; forming each battery cell from a pouch material and integrating the electrochromic material into the pouch material of the one or more battery cells; or An indicator body including the electrochromic material is formed from a metal strip that connects connector terminals associated with the one or more battery cells.

14. The method of claim 13, comprising: generating a notification when the voltage is at or below the minimum voltage and / or the voltage is at or above the maximum voltage; or wherein the voltage of the one or more battery cells varies over time, and wherein the color change of the material remains permanent when the voltage is at or below the minimum voltage and / or the voltage is at or above the maximum voltage.

15. The method of claim 13, comprising providing a vision system comprising one or more cameras, and comprising one or more controllers receiving data from the one or more cameras to identify color changes in the material, and comprising: storing the at least one battery cell stack in a storage facility and visually monitoring the electrochromic indicators of the one or more battery cells with the one or more cameras over time; transporting the at least one battery cell stack for assembly into a vehicle and visually monitoring the electrochromic indicators of the one or more battery cells with the one or more cameras during transport; or The at least one cell stack is sent to a testing facility or a recycling facility, and the electrochromic indicators of the one or more battery cells are visually monitored at the testing facility or the recycling facility with the one or more cameras.

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