BATTERY CELL SYSTEM AND BATTERY CELL MONITORING SYSTEM

Abstract

Battery cell system (28) comprising: an anode (50) and a cathode (52) arranged in an aqueous lithium-ion solution (74) within a housing (6); a base layer (34) with a first side (44) and a second side (46), wherein the base layer (34) is effectively configured to separate the anode (50) and the cathode (52); a first contact (38) which is attached to the first side (44) of the base layer (34) and is adjacent to the anode (50) or cathode (52); a reference component (42) which is located on the second side (46) of the base layer (34); a measuring device (56) that is connected to the reference component (42); and a second contact (40) which is attached to the second side (46) of the base layer (34) and is connected via a second circuit (64) to an anode current collector (80) and to the first contact (38) via a first circuit (62), wherein the reference component (42) is arranged on the second contact (40), wherein the base layer (34), the first and second contacts (38, 40) and the reference component (42) are all effectively configured to allow ions (54) to pass through them, wherein the first and second contacts (38, 40) are each sputtered onto the base layer (34).

Description

TECHNICAL FIELD

[0001] The present disclosure generally relates to the field of lithium-ion batteries and battery modules. More specifically, the present disclosure relates to a vehicle battery having an integrated reference electrode that provides real-time feedback on the condition of a battery cell.

[0002] EP 0 981 262 A2 discloses a battery cell system with an anode, a cathode, and a diaphragm, with potential probes provided on both sides of the diaphragm. Documents DE 10 2014 001 260 A1 and US 2014 / 0 375 325 A1 disclose similar systems. BACKGROUND

[0003] A vehicle that uses one or more battery systems to provide all or a portion of the vehicle's motive power may be referred to as an xEV, with the term "xEV" being defined herein to include all subsequent vehicles, or any variations or combinations thereof, that use electrical energy for all or a portion of their motive power. For example, xEVs include electric vehicles (EVs) that use electrical energy for all motive power. As those skilled in the art will recognize, hybrid electric vehicles (HEVs), which are also considered xEVs, combine an internal combustion engine propulsion system and a battery-powered electric propulsion system, such as 48-volt (V) or 130-volt systems. The term HEV can include any variation of a hybrid electric vehicle.For example, full hybrid systems (FHEVs) can provide mechanical and other electrical power to the vehicle using one or more electric motors, using only an internal combustion engine, or using both. In contrast, mild hybrid systems (MHEVs) deactivate the internal combustion engine when the vehicle is idling and use a battery system to continue running the air conditioning, radio, or other electronics, as well as restart the engine when propulsion is desired. The mild hybrid system can also apply some power assistance, for example, during acceleration, to supplement the internal combustion engine. Mild hybrids are typically 96V to 130V and utilize regenerative braking through a belt- or crank-integrated starter-generator.For the purposes of this discussion, it should be noted that mHEVs typically do not technically use electrical energy provided directly to the crankshaft or transmission for any portion of the vehicle's propulsion power. However, an mHEV can still be considered an xEV because it uses electrical energy to supplement the required power of a vehicle when the internal combustion engine is idling and recovers braking energy through an integrated starter generator. Additionally, a plug-in electric vehicle (PEV) is any vehicle that can be charged from an external power source, such as a wall outlet, and the energy stored in the rechargeable battery packs contributes to powering the wheels.PEVs are a subcategory of EVs that includes all electric or battery electric vehicles (BEVs), plug-in hybrid electric vehicles (PHEVs), and electric vehicle conversions of hybrid electric vehicles and conventional internal combustion engines.

[0004] As described above, xEVs can provide a number of advantages compared to conventional gas-powered vehicles that use only internal combustion engines and conventional electrical systems, typically 12V systems powered by a lead-acid battery. For example, xEVs can produce fewer undesirable emissions and have higher fuel efficiency compared to conventional internal combustion vehicles. In some cases, such xEVs can completely eliminate the use of gasoline, as is the case with certain types of EVs or PEVs.

[0005] As xEV technology continues to evolve, there is a need to provide improved power sources (e.g., battery systems or modules) for such vehicles. For example, it is desirable to increase the distance these vehicles can travel without the need to recharge the batteries. Additionally, it may also be desirable to optimize the performance of these batteries and reduce the costs associated with the battery systems by monitoring the state of charge for the battery cells. For example, it is recognized that it may be desirable to provide a function, as part of the battery module, capable of providing the status of the battery cell, including, but not limited to, the state of charge (SOC). SUMMARY OF REVELATION

[0006] A summary of the embodiments disclosed herein is described below. It should be understood that these aspects are merely intended to provide the reader with a brief summary of these particular embodiments.

[0007] A battery cell separator assembly provides a base layer, a first contact, a second contact, and a reference component. The base layer includes a first side and a second side. The first contact is attached to the first side of the base layer between the base layer and an anode. The second contact is attached to the second side of the base layer. A reference component is disposed on the second contact. The battery cell separator assembly can be implemented in a variety of locations, such as, but not limited to, a vehicle battery for on-board vehicle use and in a battery cell testing device.

[0008] A battery cell system is also provided, including an anode, a cathode, a separator formed from a base layer, first and second contacts, and a reference component. The anode and the cathode are disposed in a lithium-ion non-aqueous solution within a housing. The base layer of the separator includes a first side and a second side. The base layer is operatively configured to separate the anode and the cathode within the housing. The first contact of the separator is attached to the first side of the base layer between the base layer and an anode. The second contact is attached to the second side of the base layer with the reference component disposed on the second contact.

[0009] Additionally, a battery cell testing device may also be provided, including a stator, a housing, a gauge, and a separator formed from a base layer, first and second contacts, and a reference component. The housing is operatively configured to hold an anode and a cathode in a lithium-ion solution and is disposed or mounted on the stator. The separator includes a base layer having a first side and a second side disposed in the lithium-ion solution. The base layer is operatively configured to separate the anode and the cathode in the lithium-ion solution disposed in a housing. The first contact may be attached to the first side of the base layer such that the first contact is positioned directly between the base layer and the anode.The second contact may be attached to the second side of the base layer and used as a base for the reference component. A measuring device may be connected to the reference component via the second contact, so that the measuring device reads the voltage difference between the reference component and (1) the anode current collector located on the back side of the anode; and (2) the first contact is located on the front side of the anode. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] These and other features and advantages of the present disclosure will become apparent from the following detailed description of the preferred embodiments and the best modes for carrying out the described disclosures with reference to the accompanying drawings and appended claims, in which: Fig. 1 is a perspective view of an xEV having a battery system configured to provide power to various components of the xEV in accordance with embodiments of the present disclosure. Fig. Figure 2 is a schematic sectional view of an embodiment of the xEV with the separator assembly and battery system of Fig. 1 and with a lithium-ion battery according to one aspect of the present disclosure. Fig. Figure 3A is a schematic view of the second side of a base layer (separator) with the porous gold contact layer and the porous reference component attached to the second side of the base layer. Fig. Figure 3B is a schematic view of the first side of the base layer (separator) with the porous copper contact layer attached to the first side of the base layer. Fig. 4A is a schematic cross-sectional view of a battery cell system according to several embodiments of the present disclosure. Fig. 4B is a schematic cross-sectional view of an embodiment of the battery cell test fixture of the present disclosure implemented with a test anode. Fig. 4C is a schematic cross-sectional view of an embodiment of the battery cell test fixture of the present disclosure implemented with a test cathode. Fig. 5 is an enlarged, schematic side view of the separator assembly of the present disclosure relative to an anode for a vehicle battery. Fig. 6A is an enlarged cross-sectional view of an embodiment of the present disclosure in which the reference component is directly attached to the base layer or base member. Fig. 6B is an enlarged top view of an embodiment of the present disclosure in which the reference component is directly attached to the base layer or base member.

[0011] Like reference numbers refer to like parts in the description of the several views of the drawings. DETAILED DESCRIPTION

[0012] The terms “first”, “second” and the like do not denote any arbitrary order, quantity or meaning, but serve to distinguish one element from others, while the terms “a” and “an” do not denote a limitation of the quantity, but the presence of at least one of the items mentioned.

[0013] The battery systems described herein can be used to power a number of different types of xEVs, as well as other energy storage applications (e.g., utility grid storage systems). Such battery systems can include one or more battery modules, each battery module having a number of battery cells (e.g., lithium-ion electrochemical cells) arranged to provide specific voltages and / or currents useful for powering, for example, one or more components of an xEV. Generally, the battery cells include electrochemical materials (e.g., electrolytes, active electrode materials) that are responsible for much of the electrical activity of the battery cell.The electrochemical materials are housed within and supported by certain mechanical features of the cell, such as a battery cell casing 6, a battery cell current collector, and so on.

[0014] A detailed view of the battery system 12 is shown in Fig. 2. As illustrated, the vehicle propulsion system 8 may include an energy storage component 14 connected to an ignition system 16, an alternator 18, a vehicle console 20, and optionally an electric motor 22. Generally, the energy storage component 14 may capture / store electrical energy generated in the vehicle 10 and output electrical energy to power electrical devices in the vehicle 10. The energy storage component 14 may further include the lithium-ion battery cell system 28 of the present disclosure and a lead-acid battery 30.

[0015] In other words, the vehicle propulsion system 8 may supply components to the vehicle's electrical system, which may include cooling fans, air conditioning systems, electric power steering systems, active suspension systems, car parking systems, electric oil pumps, electric super / turbochargers, electric water pumps, heated windshield / defrosters, power window motors, vanity mirror lights, tire pressure monitoring systems, sunroof motors, power seats, alarm systems, infotainment systems, navigation functions, lane departure warning systems, electric parking brakes, exterior lights, or any combination thereof. For example, in the illustrated embodiment, the energy storage component 14 supplies energy to the vehicle console 20 and the ignition system 16, which may be used to start (e.g., crank) the internal combustion engine 24.

[0016] Additionally, the energy storage component 14 can capture electrical energy generated by the alternator 18 and / or the electric motor 22. In some embodiments, the alternator 18 can generate electrical energy while the internal combustion engine 24 is operating. In particular, the alternator 18 can convert the mechanical energy generated by rotating the internal combustion engine 24 into electrical energy. Additionally or alternatively, if the vehicle 10 includes an electric motor 22, the electric motor 22 can generate electrical energy by converting mechanical energy generated by the motion of the vehicle 10 (e.g., rotation of the wheels) into electrical energy. Thus, in some embodiments, the energy storage component 14 can capture electrical energy generated by the alternator 18 and / or the electric motor 22 during regenerative braking.As such, the alternator and / or electric motor 22 are generally referred to herein as a regenerative braking system.

[0017] To facilitate the sensing and delivery of electrical energy, the energy storage component 14 may be electrically connected to the vehicle's electrical system via a bus 26. For example, the bus 26 may enable the energy storage component 14 to receive electrical energy generated by the alternator 18 and / or the electric motor 22. Additionally, the bus 26 may enable the energy storage component 14 to output electrical energy to the ignition system 16 and / or the vehicle console 20. Accordingly, when a 12-volt battery system 12 is used, the bus 26 may typically carry electrical power between 8 and 18 volts.

[0018] Additionally, as illustrated, the energy storage component 14 may include multiple battery modules. For example, in the illustrated embodiment, the energy storage component 14 includes a lithium-ion battery 28 and a lead-acid battery 30, each including one or more battery cells. In other embodiments, the energy storage component 14 may include any number of battery modules. Additionally, although the lithium-ion battery module 28 and the lead-acid battery module 30 are illustrated adjacent to each other, they may be positioned in different areas around the vehicle. For example, the lead-acid battery module 28 may be positioned in or around the interior of the vehicle 10, while the lithium-ion battery module 28 may be positioned under the hood of the vehicle 10.

[0019] To facilitate controlling the capture and storage of electrical energy, the drive system 8 may additionally include a control module 32. In particular, the control module 32 may control operations of components in the battery system 12, such as relays (e.g., switches) within the energy storage component 14, the alternator 18, and / or the electric motor 22. For example, the control module 32 may regulate the amount of electrical energy captured or delivered by each battery module 28 or 30, perform load balancing between the battery modules 28 and 30, determine a state of charge of each battery module 28 or 30, determine the temperature of each battery module 28 or 30, determine the control voltage output by the alternator 18 and / or the electric motor 22, and the like.

[0020] In accordance with at least selected embodiments or objects, one aspect of the present disclosure provides a separator for a lithium-ion battery, such as a lithium-ion battery (although use of the separator with other batteries is also contemplated), wherein the separator assembly 36 comprises a porous, permeable, or semi-permeable composite material having a microporous substrate and a coating layer formed on at least one surface of the porous substrate, wherein the surface coating is formed from particles and / or a mixture of particles (inorganic and / or organic particles) and an aqueous or water-based polymeric binder.

[0021] The separator assembly 36 described herein may be advantageous due to its additional capability to provide cell status for a lithium-ion battery. This improved, optimized, new, or modified separator for a lithium-ion battery includes a base layer 34. The base layer 34 may be coated with a mixture of one or more types of particles (e.g., inorganic particles such as ceramic particles and / or organic particles such as high-temperature polymer particles) and one or more aqueous or water-based polymeric binders, wherein an aqueous or water-based polymeric binder may include one or more typically water-insoluble polymers (such as PVDF and / or various copolymers thereof) and, in certain embodiments, further one or more typically water-soluble polymers (such as, for example, polyvinyl alcohol or polyacrylic acid).The coating can prevent oxidation reactions from occurring at the interfaces of the coated separator and the electrodes in the battery and / or can improve the safety and / or overall performance of a lithium-ion battery.

[0022] As stated, the ceramic coating helps maintain the integrity of the separator's base layer 34. The particles can be in a variety of shapes, such as, but not limited to, rectangular, spherical, elliptical, cylindrical, oval, bone-shaped, or shapeless. The "particles" can also be fibrous or fiber-shaped. The particles, in some embodiments, are very small and can therefore have a high surface area per gram, which can enhance the absorption performance of the coating material and the interaction of the particles with the polymer matrix.Furthermore, in some embodiments, the particles as purchased from the particle manufacturer may be precoated with a material, for example, to improve the compatibility of the particle with a polymeric matrix, to improve the dissolution of the particles in a portion of the polymer matrix, to improve the dispersibility of the particles in the polymer matrix to avoid particle agglomeration, and / or to stabilize the particles in the coating slurry.

[0023] It should be understood that the base layer, reference component, separator assembly 36, first contact 38, and second contact 40 described herein may be referred to as permeable, semipermeable, or porous throughout the present invention. Regardless of the terms used—"permeable," "semipermeable," or "porous"—all should be understood to mean the ions are permeable to a variety of degrees depending on the type of material used (and the process used to manufacture / assemble, such as sputtering / screen printing / painting, etc.) of the base layer, reference component, separator assembly, and / or first / second contacts.

[0024] With reference to the Fig. 3A-3B, 4A, and 5, a battery cell separator assembly 36 according to the present disclosure may include a base layer 34, a first contact 38, a second contact 40, and a reference component 42. The second contact 40 is shown in dashed lines to indicate that the second contact 40 may not be used, and the reference component 42 may therefore be attached directly to the base layer 34—as in Fig. 6. The base layer 34 may have a first side 44 and a second side 46, as shown. The first contact 38 may, but not necessarily, be formed of copper when used with an anode electrode. Also, the first contact 38 may, but not necessarily, be formed of gold when used with the cathode electrode. The second contact 40 may, but not necessarily, be formed of gold or another similar low-resistance material. Referring to Fig. 4A, an optional middle separator 35 is shown, which prevents the reference material 42 from contacting any structure other than the base layer and / or the second contact 40. It is understood that instead of using an optional middle separator, as in Fig. 4A, the reference material may be powdered or coated with a ceramic material or the like to protect the reference material from short circuits if it contacts other structures in the battery.

[0025] As in the Fig. 3, Fig. 4A and Fig. 5, the first contact 38 may be secured to the first side 44 of the base layer 34 such that the first contact 38 is sandwiched between the base layer 34 and an electrode 48, which may be an anode or a cathode. In this arrangement, the first contact 38 is located near or adjacent to the electrode 48, as shown in Fig. 5. The second contact 40, when implemented, may be disposed on the second side 46 of the base layer 34; and a reference component 42 may be disposed on the second contact 40.

[0026] The reference component 42 is operatively configured to be porous and / or to allow the lithium ions 54 to pass through the reference component 42. The porous construction is achieved by spraying or screen printing (or a similar process) the material onto the base layer 34, which may have a ceramic coating. The resulting arrangement for the reference component 42 is shown in Fig. 6. The reference component may be formed from a material such as iron phosphate, lithium titanate, or another similar metal oxide. It should be understood that the reference component 42 is formed from a material that has a constant voltage (or barely varies) regardless of the state of charge—except for a very low or very high state of charge. By having a constant voltage, the reference component 42 allows a user / system to compare the fixed voltage to other points in a system. Furthermore, the reaction kinetics of the material of the reference component 42 should be easy so that the small amount of current flow allowed by the measuring device 56 to obtain a measurement of the voltage differences 58, 60 should not cause polarization of the reference voltage itself.

[0027] It is understood that the metal oxide used for the reference component 42 can be mixed with a hydrocarbon binder and a solvent to form a slurry. The reference component 42 can then be sprayed, screen-printed, or drawn onto the second contact 40 to render the reference component 42 porous, allowing the lithium ions 54 to pass through the reference component 42 itself. Furthermore, the base layer 34 can also be formed from filler material that enables or causes anisotropic electrical and / or thermal conduction. For example, the base layer 34 can include nanomaterials such as metallic, semi-metallic, or carbon-based nanoparticles, nanotubes, nanofibers, sheet or graphene layers, or the like. Furthermore, certain fillers can be used to provide enhanced structural properties.In addition to or instead of conductive fillers, structural fillers such as fibers, beads, granules, or the like, made of a ceramic material, such as a silicate or borosilicate glass, or any other suitable material may be used. The base layer 34 may also include a porous material such as a polyolefin (e.g., polyethylene, polypropylene), a polyarene (e.g., polystyrene, polyphenylene sulfide), or the like, which further allows lithium ions 54 to pass through the base layer 34.

[0028] With further reference to the Fig. 4A and Fig. 5, the battery cell separator assembly 36 may also include a measuring device 56 (shown in Fig. 4A) operatively configured to read a first voltage 58 between the first contact 38 and the second contact 40 via a first circuit 62 or electrical communication therebetween. It should be understood that the same meter 56 or a different meter may be implemented that reads a second voltage 60 between the second contact 40 and an anode current collector 80 via a second circuit 64 or electrical communication therebetween.

[0029] With respect to all embodiments of the present disclosure, the second voltage 60 (from the back of the anode / cathode) can be read with the first voltage 58 (from the front 66 of the anode / cathode) to determine the condition of the electrode 48 (anode / cathode), the stability of the electrode 48, as well as the SOC of the electrode 48, among other factors. All of this data can be used in various settings. In a product development or laboratory setting, the data could be used to develop a mathematical model for a particular battery so that the mathematical model could be implemented on such batteries when implemented at the production level in commercial vehicles.The mathematical model would be implemented (instead of a wired voltmeter and associated circuitry in the battery) to provide real-time battery feedback to a vehicle user or to a remote location that can monitor or manage the battery. Alternatively to using the first and second voltages and other battery data to develop a mathematical model, the data can simply be routed from the circuitry and voltmeter 56 to a control module, which then communicates the data and / or battery conditions to the vehicle user (where the separator assembly 36 is used on a work vehicle) or to a remote location or user. One non-limiting example where remote battery monitoring may be useful is in an electric fleet vehicle, where battery charges and battery health can be remotely controlled.Accordingly, the resulting data and / or model can be used to accurately identify the SOC and protect the battery (e.g., identifying lithium plating at the anode; or data can notify users when battery limits are reached or close to the limits to protect the lithium-ion battery.

[0030] It should be understood that the reference component 42 may be used in a variety of environments where it is desirable to have an unobtrusive reference electrode that could be attached to any base member. Accordingly, the reference electrode of the present disclosure includes a porous reference component 42, wherein the base layer 34 may be any base member 34 (not necessarily a separator or a base layer 34 for a separator in a battery environment). However, similar to the battery environment, the reference component 42 may be coupled to a base member 34 directly or via a contact 40, where the reference component 42 may be porous or semi-permeable, allowing a variety of ions to pass through the reference component.Accordingly, a reference structure 43 may be formed from the reference component 42 as described in conjunction with a base member 34, wherein the reference component 42 may be in electrical communication with at least one electrode current collector 80 or a first contact 38. As indicated, the reference component 42 is formed from a material such as, but not limited to, iron phosphate, which may be coupled to the base layer and / or a contact via a screen printing process, a spray painting process, or the like to achieve the porous and / or semi-permeable structure for the reference component 42. However, to the extent that a contact 40 is used, the contact 40 may not necessarily be sputtered onto the base member 34, allowing ionic material to pass through the second contact as well.

[0031] Accordingly, with reference to Fig. 4A, a lithium-ion battery cell system 28 may also be provided according to various embodiments of the present disclosure. The battery cell system 28 may incorporate a base layer, the first and second contacts, and the reference component as a separator assembly, so that the battery cell system 28 can be monitored in real time on a vehicle. Accordingly, the aforementioned battery cell system 28 may be installed on a vehicle, providing a user with information about the state of charge and the battery condition.The battery cell system 28 may include an anode 50 and a cathode 52 disposed in a non-aqueous lithium-ion solution 74 within a hermetically sealed housing 6, in addition to a separator 36 or separator assembly unit, which in turn may consist of a base layer 34, a first contact 38, a second contact 40, and a reference component 42, all of which may be integrated into the separator assembly. The base layer 34 may have a ceramic coating and includes a first side 44 and a second side 46. The base layer 34 is operatively configured to separate the anode and the cathode in the aqueous lithium-ion solution 74. The first contact 38 is affixed to the first side 44 of the base layer 34 between the base layer 34 and an anode. The second contact 40 is attached to the second side 46 of the base layer 34 with the reference component 42 arranged on the second contact 40.Both the first and second contacts have a porous composition that allows lithium ions 54 to pass through the contacts. This porous composition is achieved by performing a process such as sputtering, wherein the contact material is deposited onto the base layer 34 atom by atom. The reference component 42 for each electrode (shown as anode 50 and cathode 52) also has a porous composition that allows lithium ions 54 to pass through the reference component 42. It is understood that the reference component 42 may be a metal oxide mixed with a hydrocarbon binder and a solvent to form a slurry. The reference component 42 may be deposited onto the base layer 34 (or onto the second contact 40, if implemented) using a process such as screen printing, spraying, or the like.Accordingly, the reference component 42, as well as the base layer 34 and the contacts, are sufficiently porous to allow the lithium ions 54 to pass through the reference component 42 and the base layer 34. The reference component 42 / first and second contacts in the battery cell system are similar to those in the separator assembly 36, in that the reference component 42 may be made of a material such as iron phosphate or the like, while the first contact 38 may be formed of a material such as, but not limited to, copper, and the second contact 40 may be formed of a low-resistivity material such as gold.

[0032] In addition, the base layer 34 can also be formed from filler material that enables or causes anisotropic electrical and / or thermal conduction. For example, the base layer 34 can include nanomaterials, such as metallic, semi-metallic, or carbon-based nanoparticles, nanotubes, nanofibers, sheet or graphene layers, or the like. Furthermore, certain fillers can be used to provide improved structural properties. In addition to or instead of conductive fillers, structural fillers such as fibers, beads, granules, or the like made of a ceramic material, such as a silicate or borosilicate glass, or any other suitable material can be used. The base layer 34 can also be porous material, but is not limited to polyolefin (e.g., polyethylene, polypropylene), a polyarene (e.g.,Polystyrene, polyphenylene sulfide), or the like, which further enable lithium ions 54 to pass through the base layer 34. The battery system may also include a meter 56 operatively configured to read a first voltage 58 between the first contact 38 and the second contact 40 via a first electrical communication therebetween.

[0033] It is understood that the battery cell system 28 may be arranged with a meter 56 on a commercial electric vehicle to enable a vehicle user to monitor the battery's condition in real time via the meter 56 itself or via a vehicle control module (module 88), which may or may not be integrated as part of a user interface 86 in communication with the battery cell. It is also understood that the battery cell system 28 of the present disclosure may engage in a remote connection, located at a remote base location, with the user interface 86 so that the remote user interface can remotely monitor the condition of the battery system of the present disclosure and, optionally, be remotely managed along with other such vehicles, the vehicle being part of a fleet.

[0034] Accordingly, in the battery cell system 28 of the present disclosure, to monitor the state of charge of a vehicle battery cell among other objects, the first contact 38 may be attached to the first side 44 of the base layer 34, as shown in Fig. 5. This location, in close proximity to the first contact 38, adjacent to the front surface 66 of the anode, offers the advantage of obtaining the voltage at the front surface of the electrode 48 (rather than the back surface of the electrode 48). The voltage at the front surface 66 of the electrode 48 is more relevant for some aspects of cell control or state and SOC (state of charge) estimations. Furthermore, since the first contact 38, the second contact 40, the base layer 34, and the reference material are all formed from porous material via processes such as sputtering, spray painting, or similar methods, as discussed herein, the aforementioned components are all effectively configured to allow lithium ions 54 to pass through the separator assembly 36, and the separate integrated reference electrode 48 does not interfere with the operation of the battery cell.

[0035] Accordingly, because the first voltage 58 can be obtained at the front surface 66 of the electrode 48 while allowing lithium ion passage, the present disclosure provides more accurate data feedback for the electrode 48. Furthermore, the meter 56 as provided via the present disclosure is operatively configured to read a first voltage 58 between the first contact 38 (near the front surface 66 of the electrode 48) and the second contact 40 (associated with the reference component 42) via a circuit therebetween. The meter 56 may also be operatively configured to read a second voltage 60 between an electrode collector 80 (adjacent the back surface 68 of the electrode 48) and the second contact 40 (associated with the reference component 42).The first and second voltages from the front and back surfaces 66, 68 of the electrode 48 provide the user with accurate voltage data for the electrode 48.

[0036] With reference to the Fig. 4B and Fig. 4C, the battery cell separator assembly 36 of the present disclosure may also be implemented as part of a test apparatus 70 as provided by the present disclosure. Accordingly, a battery cell test apparatus 70 may be provided, wherein the battery cell test apparatus 70 includes a post 72, a base layer 34 disposed in a lithium-ion solution 74, a first contact 38, a second contact 40, a reference component 42, and a measurement device 56. The post 72 of the battery cell test apparatus 70 is operatively configured to hold an anode 50 and a cathode 52 in a lithium-ion solution 74. The anode 50, the cathode 52, and the lithium-ion solution 74 may be disposed within a hermetically sealed housing 6, which is then disposed or attached to the post 72.It is also understood that a base layer 34, acting as a separator, may also be disposed in the lithium-ion solution 74 to separate the anode 50 and the cathode 52.

[0037] The base layer 34 may also be formed from filler material that enables anisotropic electrical and / or thermal conduction and may be coated with a ceramic material to maintain / protect the integrity of the filler material. For example, the base layer 34 may include nanomaterials, such as metallic, semi-metallic, or carbon-based nanoparticles, nanotubes, nanofibers, sheet or graphene layers, or the like. Furthermore, certain fillers may be used to provide improved structural properties. In addition to or instead of conductive fillers, structural fillers such as fibers, beads, granules, or the like, made of a ceramic material, such as silicate or borosilicate glass, or any other suitable material may be used. The base layer 34 may also include polymeric material such as polyolefin (e.g.,Polyethylene, polypropylene), a polyarene (e.g., polystyrene, polyphenylene sulfide), or the like, which further allow lithium ions 54 to pass through the base layer 34. As previously mentioned, the base layer 34 of the separator assembly 36 may also include a ceramic coating to maintain the integrity of the separator base layer 34 and the separation of the anode and cathode. The base layer 34, having a first side 44 and a second side 46, may be disposed in the lithium-ion solution 74 of a test battery cell 90.

[0038] The base layer 34, together with the first contact 38, the second contact 40 and the reference component 42, forms a separator assembly 36. The first contact 38 may be attached to the first side 44 of the base layer 34 between the base layer 34 and the anode to transmit data or voltage to the front side 66 of the electrode 48 (as anode 50 in Fig. 4C or cathode 52 in Fig. 4B). The battery cell tester 70 provides an electrical connection between the first contact 38 and the second contact 40, wherein the meter 56 can obtain a first voltage 58 between the first and second contacts. It is understood that the first contact 38 can be formed from copper or another similar conductive material sputtered onto the first side 44 of the base layer 34 such that the first contact 38 is also porous and allows lithium ions 54 to pass through the separator to the anode. It is also understood that the second contact 40 can be formed from gold or another similar material, but not necessarily as shown. Similar to the first contact 38, the second contact 40 can also be sputtered onto the second side 46 of the base layer 34 such that the second contact 40 is also porous and allows lithium ions 54 to pass through the separator.

[0039] As in Fig. 5, the second contact 40 can serve as an electrical conduit to the gauge 56 for the reference component 42 with the otherwise high resistance of the separator. Accordingly, the second contact 40 can serve as a means for measuring voltage (via the gauge 56) between the reference component 42 and other portions of the battery cell for obtaining voltage, such as the anode collector 80, which can be located on the back side 68 of the anode, as shown, and the first contact 38, which can be located near the front side 66 of the anode, as shown.

[0040] Similar to the reference component 42 of the previously described separator assembly 36, the reference component 42 of the battery cell tester 70 can also be sprayed, printed (or similarly coated) onto the second contact 40 (where used) on the second side 46 of the base layer 34 to provide a porous reference component 42 that allows the lithium ions 54 to pass through the reference component 42, the second contact 40, and the base layer 34. When the second contact 40 is not used, the reference component 42 is sprayed / printed / etc. directly onto the coated base layer 34 of the separator assembly 36. Similar to the previous components in the separator assembly 36 and the battery cell system, the second contact 40 can be formed from copper or another similar material that is also porous and allows the lithium ions 54 to pass through.In order to obtain a porous structure in the second contact 40, the second contact 40 may, but not necessarily, be sputtered onto the second side 46 of the base layer 34.

[0041] The battery cell tester 70 may further include a meter 56 operatively configured to read a first voltage 58 between the first contact 38 and the reference component 42 (optionally through a second contact 40) via a first circuit 62 therebetween. The first voltage 58 is particularly useful because this voltage is referenced to the front surface 66 of the electrode 48 and can be compared to the second voltage 60 from the back surface 68 of the electrode 48 to determine many operating conditions for the battery cell under test. It should be understood that the first voltage 58 from the front surface 66 of the electrode 48 has generally been unavailable due to prior concerns about monitoring equipment that impedes the passage of lithium ions 54.However, the same measuring device 56 for reading the first voltage 58 may not necessarily be used to also read a second voltage 60 between the reference component 42 (directly or via a second contact 40) and a current collector 80 (on the backside 68 of the electrode 48) via a second circuit 64 therebetween. Accordingly, the porous nature of the first and second contacts attached to the base layer 34, as well as the porous nature of the reference component 42, allows the battery cell tester to obtain a voltage measurement at the front side of the electrode 48, thereby providing more comprehensive data for the electrode 48.

[0042] It should be understood that the base layer 34 of the separator assembly 36 used in all embodiments of the present disclosure must have a suitable thickness, wherein the base layer 34 may consist of a single layer of material or the base layer 34 may consist of multiple layers of material. Regarding the thickness, if the base layer 34 of the separator assembly 36 is too thin, insufficient electrical insulation may occur. On the other hand, if the base layer 34 of the separator is too thick, insufficient thermal transfer may occur. Even in situations where thermal gradients are not essential from the standpoint of the separator 52, if the base layer 34 is too thick, there may also be insufficient space within the housing 6 to secure all the battery cells with a fairly thick battery cell separator 52.As a non-limiting example, the base layer 34 may, but is not necessarily, have an acceptable thickness between about 0.025 mm and about 0.05 mm.

[0043] In another embodiment for the battery cell testing apparatus 70 of the present disclosure, the testing apparatus may include a user interface 86 and a separator assembly 36 in communication with the user interface. The separator assembly 36 may be operatively configured to be used with a plurality of test batteries 90 sequentially as each test battery is evaluated over a period of time. The separator assembly 36 includes an integrated reference electrode 47 formed from at least one transmissive reference component 42 affixed to the base layer 34 via a screen-printing process or the like.It is understood that the permeable reference component 42 may be semi-permeable or fully permeable depending on the degree of porosity of the reference component, the type of material used in the reference component, or the method used to attach the reference component to the base layer 34—painting, printing, or the like. The separator assembly 36 is operatively configured to communicate with a current collector of one of the plurality of test batteries 90, a measurement device 56, and the user interface 86.

[0044] The battery cell testing apparatus 70 may, but does not necessarily, include a stand 72 coupled to at least one of the user interface 86, a test battery 90, or a separator assembly 36. It is understood that the separator assembly 36 includes a base layer having a first side and a second side 44, 46, with the semi-permeable reference component 42 coupled to the second side 46 of the base layer 34. The permeable reference component 42 may be operatively configured to allow ions 54 to pass through the reference electrode (including the reference component 42, optionally the first contact 38, and the second contact 40). It is understood that the separator assembly 36 is operatively configured to separate the anode 50 and the cathode 52 in each of the plurality of test batteries 90 used with the testing apparatus.Similar to previous embodiments, the permeable first contact 38 may be attached to a first side 44 of the base layer via a sputtering process or the like, so that the first contact is also permeable to ions. The first contact 38 may communicate with the reference component 42 via a first circuit.

[0045] As in the Fig. 4B and Fig.4C, the first contact is operatively configured to be adjacent to an electrode (either the anode 50 or the cathode 52, or both) in one of the plurality of test batteries. It is also understood that a second contact 40 may be attached to the reference component 42 and the second side 46 of the base layer. The second contact may communicate with a current collector of a test battery via a second circuit. Like the first contact 38, the second contact 40 may have a transmissive structure and is attached to the base layer 34 via a sputtering process or the like to achieve the transmissive structure. It is understood that the user interface 86 includes a module 88 in communication with the first and second circuits 62, 64 such that the module 88 may determine the status of the test cell via a model or the like based on receiving the first and second voltages.The user interface 86 may be located on the vehicle for a vehicle user to obtain data. Alternatively, the user interface 86 may be located at a remote base location, remotely controlling data or first / second voltages to remotely manage the electric vehicle—perhaps as part of an electric vehicle fleet. The module 88 then outputs the status of the test cell (such as the state of charge or the condition of the test cell relative to the cell boundaries, etc.) to a user via the user interface 86.

Claims

[1] Battery cell system (28) comprising: an anode (50) and a cathode (52) arranged in an aqueous lithium-ion solution (74) within a housing (6); a base layer (34) having a first side (44) and a second side (46), the base layer (34) being operatively configured to separate the anode (50) and the cathode (52); a first contact (38) attached to the first side (44) of the base layer (34) and located adjacent to the anode (50) or cathode (52); a reference component (42) disposed on the second side (46) of the base layer (34); a measuring device (56) connected to the reference component (42); and a second contact (40) attached to the second side (46) of the base layer (34) and connected to an anode current collector (80) via a second circuit (64) and to the first contact (38) via a first circuit (62), the reference component (42) being arranged on the second contact (40), wherein the base layer (34), the first and second contacts (38, 40) and the reference component (42) are all operatively configured to allow ions (54) to pass therethrough, wherein the first and second contacts (38, 40) are each sputtered onto the base layer (34). [2] Battery cell system (28) according to claim 1, wherein the base layer (34), the first and second contacts (38, 40) and the reference component (42) together form a separator assembly (36) suitable for incorporation into the battery cell system (28). [3] The battery cell system (28) of claim 1, further comprising a module (88) in communication with the first and second circuits (62, 64), the module (88) being adapted to receive a first voltage (58) and a second voltage (60) from the first and second circuits (62, 64) and being adapted to provide at least one status parameter for a vehicle battery based on the first and second voltages (58, 60). [4] Battery cell monitoring system comprising: a user interface (86); and a vehicle battery (14) comprising the battery cell system (28) according to at least one of the preceding claims, wherein the battery cell system (28) has a separator arrangement (36) with an integrated reference electrode (48), wherein the battery cell system (28) is connected to the user interface (86). [5] The battery cell monitoring system of claim 4, wherein the user interface (86) is located at a remote location. [6] Battery cell monitoring system according to claim 4, wherein the user interface (86) is arranged on a vehicle (10).

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