ACTIVE PRESSURE REGULATION FOR IMPROVED BATTERY PERFORMANCE

Abstract

A vehicle comprises a pressure regulator for controlling the pressure in a vehicle battery and a method for controlling the battery pressure. A carrier plate is arranged on a first side of the battery. A pressure plate is arranged on a second side of the battery opposite the first side. The pressure plate is movable relative to the carrier plate to control the battery pressure. A cam arranged on the pressure plate is configured to rotate in order to move the pressure plate relative to the carrier plate. A camshaft rotates the cam to move the pressure plate. A motor generates a rotation at the camshaft.

Description

INITIATIONThe present disclosure relates to increasing the performance of a battery, and more particularly to controlling the pressure applied to a battery operating under high pressure conditions to increase its performance.A battery is used for supplying power to an electric vehicle. When the battery is operated under low pressure, dimers may grow between the anode and the cathode of the battery. These dimers limit the life and effectiveness of the battery. This applies in particular to a lithium metal battery (LMB). However, the dendritic growth can be reduced when the battery is operated under high pressure. Accordingly, it is desirable to provide a method and apparatus for pressurizing the battery during operation.SUMMARYIn one embodiment, a pressure regulator for regulating a pressure across a vehicle battery is disclosed. The pressure regulating device includes a support plate on a first side of the battery, a pressure plate disposed on a second side of the battery opposite the first side, the pressure plate movable with respect to the support plate to regulate the pressure of the battery, a cam disposed on the pressure plate configured to rotate to move the pressure plate with respect to the support plate, a camshaft configured to rotate the cam to move the pressure plate, and a motor configured to generate rotation on the camshaft.In addition to one or more of the features described herein, the camshaft is maintained in a fixed position relative to the carrier plate. The motor generates the rotation on the camshaft either via a rotor shaft rotated by the motor and a flexible belt connecting the rotor shaft to the camshaft to convert rotation of the rotor shaft into rotation of the camshaft or via the camshaft functioning as the rotor shaft of the motor. In one embodiment, the cam includes a first cam and a second cam, wherein the first cam and the second cam can be selectively rotated to apply a differential pressure to the entire pressure plate. The first cam is disposed at a first angle to the camshaft and the second cam is disposed at a second angle to the camshaft that is different than the first angle. The camshaft includes a first portion having the first cam and a second portion having the second cam, the first portion and the second portion being rotatable independently of each other. The cam includes a cam groove and the camshaft includes a pin rail having a transmission pin therein configured to move into the cam groove to engage the camshaft with the cam. The pressure regulator further includes a solenoid on the camshaft for controlling an axial position of the transmission pin with respect to the cam groove.In another embodiment, a method of controlling operation of a battery of an electric vehicle is disclosed. The method includes rotating a cam against a pressure plate to cause the pressure plate to move relative to a backing plate, the battery disposed between the backing plate and the pressure plate, and moving the pressure plate relative to the backing plate adjusts a pressure within the battery.In addition to one or more of the features described herein, the method further comprises rotating the cam by rotating a camshaft at a fixed location with respect to the carrier plate. The method further comprises rotating the camshaft by a motor, wherein either a rotor shaft rotated by the motor is connected to the rotor shaft via a flexible belt or the camshaft is rotated directly by the motor. The cam includes a cam groove and the camshaft includes a pin rail having a transmission pin therein, the transmission pin further being moved into the cam groove to engage the camshaft with the cam. The cam comprises a first cam and a second cam, wherein a differential pressure is further applied to the entire pressure plate by means of the first cam and the second cam.In another embodiment, a vehicle is disclosed. The vehicle includes a battery having a first side and a second side opposite the first side, and a pressure regulator. The pressure regulating device includes a support plate on the first side of the battery, a pressure plate on the second side of the battery, the pressure plate movable with respect to the support plate to regulate a pressure of the battery, a cam disposed on the pressure plate configured to rotate to move the pressure plate with respect to the support plate, a camshaft configured to rotate the cam to move the pressure plate, and a motor configured to generate a rotation on the camshaft.In addition to one or more of the features described herein, the camshaft is maintained in a fixed position relative to the carrier plate. The motor generates the rotation on the camshaft either via a rotor shaft rotated by the motor and a flexible belt connecting the rotor shaft to the camshaft to convert rotation of the rotor shaft into rotation of the camshaft or via the camshaft functioning as the rotor shaft of the motor. The cam includes a first cam and a second cam, wherein the first cam and the second cam can be selectively rotated to apply a differential pressure to the entire pressure plate. The first cam is disposed at a first angle to the camshaft and the second cam is disposed at a second angle to the camshaft that is different than the first angle. The cam includes a cam groove and the camshaft includes a pin rail having a transmission pin therein configured to move into the cam groove to engage the camshaft with the cam. The vehicle further includes a solenoid on the camshaft for controlling an axial position of the transmission pin with respect to the cam groove.The foregoing features and advantages, as well as other features and advantages of the disclosure, will be readily apparent from the following detailed description when taken in conjunction with the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGSOther features, advantages and details are set forth in the following detailed description, by way of example only, wherein the detailed description relates to the drawings. The following are shown: FIG. 1 shows an electric vehicle according to an exemplary embodiment, FIG. 2 shows a battery system for a battery of a vehicle in an exemplary embodiment, FIG. 3 is a side view of a cam in various rotational configurations, FIG. 4 is a perspective view of the battery system in another embodiment, FIG. 5 is a perspective view of the battery system in another embodiment, FIG. 6 is a perspective view of the battery system in another embodiment, FIG. 7 is a perspective view of a portion of the camshaft including a cam, FIG. 8 is a side view of the camshaft illustrating a device that engages the cam with the camshaft, FIG. 9 is a perspective view of the battery system in another embodiment; and FIG. 10 is a side view of the battery system.DETAILED DESCRIPTIONThe following description is merely exemplary in nature and is not intended to limit the present disclosure, its application, or its use. It should be noted that, in the drawings, corresponding reference numerals designate like or corresponding parts and features.According to an exemplary embodiment, FIG. 1 shows an electric vehicle 100. The electric vehicle 100 includes an electric motor 102, a battery system 104, and a controller 106. The battery system 104 includes a battery 108 having anodes 110 and cathodes 112 that tend to form dimers when operated at standard pressure or ambient pressure. The dimers degrade the performance of the battery 108. In various embodiments, the battery 108 is any battery that requires high pressure conditions to operate, such as a lithium metal battery (LMB). The battery system 104 includes a device that applies pressure to the battery 108 and is capable of adjusting or controlling the pressure as desired.The controller 106 may include processing circuitry that may include an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group), and memory that executes one or more software or firmware programs, combinatorial logic circuitry, and / or other suitable components that provide the described functionality. The controller 106 may include a non-transitory computer readable medium storing instructions that, when processed by one or more processors of the controller 106, implement a method of operating the battery system 104 to apply a pressure to the battery 108 as desired.FIG. 2 shows a battery system 200 for a battery 108 in one exemplary embodiment. The battery system 200 includes a housing 202 in which the battery 108 is housed. The housing 202 may include a bottom surface 204, a top surface 206, and sidewalls 208. Inside the housing 202 is a pressure regulating device 210 for the battery 108. The pressure regulating device 210 includes a support plate 212 on which the battery 108 is disposed, a pressure plate 214 movable relative to the support plate, and columns 216 directing movement of the pressure plate in a direction either toward or away from the support plate. The support plate 212 may be identical to the bottom surface of the housing 202. The backing plate 212 abuts a first side of the battery 108, and the pressure plate 214 abuts a second side of the battery 108 that is opposite the first side. The pressure plate 214 may be moved toward the support plate 212 to increase a pressure applied to the battery 108. The pressure plate 214 may be moved away from the support plate 212 to reduce the pressure applied to the battery 108.A pressure plate controller 218 controls movement of the pressure plate 214, and thus pressure within the battery 108. The pressure plate controller 218 includes a camshaft 220 and one or more cams disposed on the camshaft. For purposes of illustration, a first cam 222 and a second cam 224 are shown. An engine 226 is connected to the camshaft 220 and controls rotation of the camshaft. In one embodiment, the motor 226 includes a rotor shaft 227 and is connected to the camshaft 220 via a flexible belt 232 that converts rotation of the rotor shaft into rotation of the camshaft. The motor 226 may be connected to the housing 202.The camshaft 220 is connected to at least one surface of the housing 202. The camshaft 220 may be supported by bearings. For purposes of illustration, a first bearing 228 and a second bearing 230 are shown. The bearings allow free rotation of the camshaft 220. The bearings may be supported by the top surface 206 of the housing 202. Alternatively, the bearings may also be located in one or more opposing sidewalls of the housing 202. The camshaft 220 is held in a fixed position with respect to the carrier plate 212. Thus, by rotating the camshaft 220 (as well as the first cam 222 and the second cam 224), the distance between the pressure plate 214 and the support plate 212 changes as shown in FIG. 3.A pressure sensor 240 is configured to sense the pressure within the battery 108. The pressure may be sent to the controller 106 or another suitable processor. The controller 106 may control operation of the engine based on the sensed pressure in the battery 108.FIG. 3 shows a side view 300 of a cam (e.g., the first cam 222) in various rotational configurations. The cam has a base circle 302 and a protrusion 304 on one side. Base circle 302 has a first radius r 1 and protrusion 304 has a second radius r 2, which is greater than first radius r 1. The cam is disposed such that a surface of the cam is in contact with an outer surface of the pressure plate 214. The cam rotates about a pivot point O located along the camshaft 220 and held stationary with respect to the carrier plate 212. Shown is a first angle of rotation 306 at which the cam contacts the pressure plate 214 at a point along the base circle 302. As a result, the pressure plate 214 is at a first distance d 1 from the pivot point O. Shown is a second angle of rotation 308 at which the cam is in contact with the pressure plate at a point along the protrusion 304. As a result, the pressure plate 214 is spaced from the pivot point O by a second distance d 2, which is greater than d 1. Therefore, the pressure plate 214 is closer to the support plate 212 and applies greater pressure to the battery 108 when the cam is at the second rotational angle 308 rather than the first rotational angle 306.FIG. 4 shows a perspective view 400 of the battery system 200 in another embodiment. The motor 226 has a first rotor shaft 402 extending in a direction parallel to the camshaft 220 and a second rotor shaft 404 extending in an opposite direction parallel to the camshaft. The first rotor shaft 402 may be supported on a first bearing 406 connected to the top surface 206 and the second rotor shaft 404 may be supported on a second bearing 408 connected to the top surface 206. The first rotor shaft 402 is connected to the camshaft 220 at a first location 410 via a first flexible belt 412, and the second rotor shaft 404 is connected to the camshaft 220 at a second location 414 via a second flexible belt 416.FIG. 5 shows a perspective view 500 of the battery system 200 in another embodiment. The camshaft 220 is connected to the top surface 206 of the housing 202 at a first end 502 and the second bearing 230 at the second end 504 via a first bearing 228. The first end 502 of the camshaft 220 passes through the center of the motor 226 and serves as a rotor shaft of the motor. The motor 226 can therefore rotate the camshaft 220 without using a flexible belt. The motor 226 may be attached to either an upper surface 206 or a side wall 208 of the housing 202.FIG. 6 shows a perspective view 600 of the battery system 200 in another embodiment. A first end 502 of the camshaft 220 passes through a center of the motor 226 and serves as a rotor shaft of the motor. The motor 226 is fixed to a side wall 208 of the housing 202. A second end 504 of the camshaft 220 is connected to an opposing sidewall 208 of the housing 202.FIG. 7 shows a perspective view 700 of a portion of the camshaft 220 that includes a cam. The camshaft 220 includes a longitudinal groove or pin rail 702 that extends along a portion of the camshaft. A transmission pin 704 is located within the pin rail 702 and is movable to a selected position within the pin rail. The cam has a hole through which the camshaft passes. The cam is disposed along the camshaft such that the pin rail 702 passes through at least a portion of the cam. A plurality of cam grooves 706 extend radially outward from the hole at a plurality of angular positions.In operation, the transmission pin 704 is disposed in one of the cam grooves (e.g., the first cam groove 708) to retain the cam on the camshaft 220. The camshaft 220 may then be rotated to rotate the cam and apply a selected force to the pressure plate 214, FIG. 2. the relative angular position between the cam and the camshaft may be adjusted by sliding the transmission pin 704 away from the cam by the pin rail 702 until it exits the first cam groove 708. The cam is then rotated with respect to the camshaft 220 or the camshaft is rotated with respect to the cam until the pin rail 702 aligns with another one of the cam grooves (e.g., the second cam groove 710). The gear pin 704 is then slid through the pin rail 702 to engage the cam in the second cam groove 710.FIG. 8 shows a side view 800 of the camshaft 220 illustrating a device that engages the cam with the camshaft 220. The camshaft 220 includes a cam housing 802 and a core 804 slidable within the cam housing 802. The core 804 includes a first cavity 806 on a side of the first cam 222 and a second cavity 808 on a side of the second cam 224. A first gear pin 810 is disposed in the first cavity 806 with a first spring 812 biasing the first gear pin toward the first cam 222. A second gear pin 816 is disposed in the second cavity 808 with a second spring 814 that biases the second gear pin toward the second cam 224.At one end of the camshaft 220, a solenoid 818 is disposed. The core 804 includes a magnetic material 819 located within the solenoid 818. When the solenoid 818 is off, the core 804 is in a first axial position within the cam housing 802 in which the first cavity 806 and the second cavity 808 are spaced from the first cam 222 and the second cam 224, respectively.When the solenoid 818 is energized (first configuration 820), the core 804 is forced into a second axial position within the cam housing in which the first cavity 806 is moved toward the first cam 222 and the second cavity 808 is moved toward the second cam 224. As shown, the first cam 222 is rotated at an angle at which the first gear pin 810 is not aligned with one of the cam grooves of the first cam. This compresses the first spring 812, but the first gear pin 810 does not engage the first cam 222. However, the camshaft may be rotated to align the first transmission pin 810 with a selected cam groove, and the first spring 812 then biases the first transmission pin into the selected cam groove to engage the first cam 222. In addition, the second cam 224 is rotated at an angle at which the second gear pin 816 is aligned with a cam groove of the second cam 224. Thus, the second spring 814 may bias the second gear pin 816 to engage the second cam 224.Referring again to FIG. 2, the first cam 222 and the second cam 224 may have different angular positions, as the angular position of a cam with respect to the camshaft 220 may be selected. For example, the first cam 222 may be set at a first angle θ and the second cam 224 may be set at a second angle (e.g., θ+5°). In this configuration, with equal rotation of the camshaft 220, the second cam 224 may exert more force on the pressure plate than the first cam 222. Thus, differential force and differential pressure can be applied to the entire movable plate and at various locations in the battery.FIG. 9 shows a perspective view 900 of the battery system 200 in another embodiment. The camshaft 220 includes a first portion 902 having the first cam 222 and a second portion 904 having the second cam 224. The first portion 902 and the second portion 904 may be rotated independently of each other. A first motor 906 is connected to the first portion 902 and a second motor 908 is connected to the second portion 904. The first motor 906 and the second motor 908 may be operated independently to cause different rotations of their first cam 222 and the second cam 224, respectively. Thus, different pressures may be applied at different locations of the battery 108. It should be noted that in various embodiments, the camshaft 220 may have more than two portions rotating independently of each other, each portion including a separate cam.FIG. 10 shows a side view 1000 of the battery system 200. The side view shows a first camshaft 1002 and a second camshaft 1004 at different locations along the pressure plate 214. The camshafts may be arranged to generate a desired pressure at various locations along the pressure plate. Each camshaft can be rotated independently. Note that there may be more than two camshafts in various embodiments.The term "a", "an" does not represent a quantity limitation, but rather indicates that at least one of the mentioned objects is present. Unless the context clearly indicates otherwise, the term "or" means "and / or.". When the description discusses "an aspect", this means that a particular element described in connection with the aspect (e.g., a feature, structure, step, or characteristic) is included in at least one of the aspects described herein and may or may not occur in other aspects. It is also to be understood that the described elements may be combined in any suitable manner in the various aspects.When an element such as a layer, film, region or substrate is referred to as being "on" another element, it may be directly on the other element or intervening elements may also be present. In contrast, there are no intervening elements when an element is referred to as being "directly on" another element.Unless otherwise specified herein, all testing standards are latest standards in effect on the filing date of this application or, when a priority is claimed, on the filing date of the earliest priority application in which the testing standard appears.Unless otherwise specified, all technical and scientific terms used herein have the meaning commonly understood by one of ordinary skill in the art to which this disclosure pertains to these terms.Although the above disclosure has been described with reference to exemplary embodiments, those skilled in the art will appreciate that various changes may be made and equivalent elements may be substituted without departing from the scope thereof. Moreover, many changes may be made to adapt a particular situation or material to the teachings of the disclosure without departing from its essential scope. Therefore, the present disclosure is not intended to be limited to the specifically disclosed embodiments, but to include all embodiments falling within its scope.

Claims

A pressure regulating device for regulating a pressure on a battery of a vehicle, comprising: a backing plate on a first side of the battery; a pressure plate disposed on a second side of the battery opposite the first side, the pressure plate being movable with respect to the backing plate to regulate the pressure of the battery; a cam disposed on the pressure plate configured to rotate to move the pressure plate with respect to the backing plate; a camshaft configured to rotate the cam to move the pressure plate; and a motor configured to generate a rotation on the camshaft.The pressure regulating device of claim 1, wherein the camshaft is maintained in a fixed position with respect to the support plate.The pressure control apparatus of claim 1, wherein the motor generates the rotation on the camshaft either (i) via a rotor shaft rotated by the motor and a flexible belt connecting the rotor shaft to the camshaft to convert rotation of the rotor shaft into rotation of the camshaft, or (ii) via the camshaft functioning as the rotor shaft of the motor.The pressure control apparatus of claim 1, wherein the cam comprises a first cam and a second cam, wherein the first cam and the second cam can be selectively rotated to apply a differential pressure to the entire pressure plate.The pressure regulating device of claim 1, wherein the cam comprises a cam groove and the camshaft comprises a pin rail having a transmission pin therein configured to move into the cam groove to engage the camshaft with the cam.A method of controlling operation of a battery of an electric vehicle, comprising: rotating a cam against a pressure plate to cause the pressure plate to move relative to a backing plate, wherein the battery is disposed between the backing plate and the pressure plate, and moving the pressure plate relative to the backing plate adjusts a pressure within the battery.The method of claim 6, further comprising rotating the cam by rotating a camshaft at a fixed location with respect to the carrier plate.The method of claim 7, further comprising rotating the camshaft via a motor, wherein either: (i) a rotor shaft rotated by the motor is connected to the rotor shaft via a flexible belt; or (ii) the camshaft is rotated directly by the motor.The method of claim 7, wherein the cam comprises a cam groove and the camshaft comprises a pin rail having a transmission pin therein, the transmission pin further being moved into the cam groove to engage the camshaft with the cam.The method of claim 6, wherein the cam has a first cam and a second cam, further comprising applying a differential pressure to the entire pressure plate by means of the first cam and the second cam.

Images