Patent Publication Number: US-2023147331-A1

Title: Energy storage system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority under 35 U.S.C. § 119 to Korean Application No. 10-2021-0152588, filed in Korea on Nov. 8, 2021, whose entire disclosure is hereby incorporated by reference. 
     BACKGROUND 
     1 Field 
     The present disclosure relates to an energy storage system, and more particularly, to an energy storage system for cooling a battery (or the like) using a fluid. 
     2. Background 
     Up to now, a heat dissipation of most energy storage system mainly adopts forced convection using a fan or natural convection using a heat sink. Commercial and industrial energy storage systems are adopting an air-cooling method using a fan, and a home energy storage system may be using a natural convection method. In the example of home energy storage systems, since the capacity is small compared to commercial and industrial energy storage systems, heat of a heating element can be dissipated to a heat sink. In the example of large-capacity commercial and industrial energy storage systems, an air cooling method using a fan is mainly adopted. This is because that when a fan is attached, parts that generate more heat with natural convection can be easily cooled with the fan, compared to natural convection. 
     U.S. Pat. No. 8,448,696 B2, the subject matter of which is incorporated herein by reference, discloses a water cooling structure for cooling a power converter and a battery pack using a four-way valve. The above document discloses the use of a four-way valve in order to use four operation modes with a single shape valve. 
     However, when using a four-way valve, when flows are sent in two or three directions, a large amount of flow may occur in one direction. The four-way valve has a problem in that the flow may be temporarily stopped when changing the direction and opening/closing the flow. When using a four-way valve, there is a problem in that two pumps must be used to change the direction of flow. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Arrangements and embodiments may be described in detail with reference to the following drawings in which like reference numerals refer to like elements and wherein: 
         FIG.  1    is a schematic diagram of an energy storage system according to an embodiment of the present disclosure; 
         FIG.  2    is a perspective view of a first valve or a second valve according to an embodiment of the present disclosure; 
         FIG.  3 A  is a cross-sectional view of one side of a control valve when fluid (or water) is supplied to a first outlet (or a first load part); 
         FIG.  3 B  is a cross-sectional view of the other side of the control valve when fluid is supplied to the first outlet; 
         FIG.  4 A  is a cross-sectional view of one side of the control valve when fluid is supplied to a second outlet (or second load part); 
         FIG.  4 B  is a cross-sectional view of the other side of the control valve when fluid is supplied to the second outlet; 
         FIG.  5 A  is a cross-sectional view of one side of the control valve when fluid is supplied to the first outlet and the second outlet; 
         FIG.  5 B  is a cross-sectional view of the other side of the control valve when fluid is supplied to the first outlet and the second outlet; 
         FIG.  6    is a block diagram of a controller and a configuration related thereto according to an embodiment of the present disclosure; 
         FIG.  7    is a schematic diagram for explaining the flow of a fluid in a simultaneous cooling mode of the energy storage system of the present disclosure; 
         FIG.  8    is a schematic diagram for explaining the flow of a fluid in a combined mode of the energy storage system of the present disclosure; 
         FIG.  9    is a schematic diagram for explaining the flow of a fluid in a battery pack cooling mode of the energy storage system of the present disclosure; and 
         FIG.  10    is a schematic diagram for explaining the flow of a fluid in a power converter cooling mode of the energy storage system of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Advantages and features of the present disclosure and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below, but may be implemented in various different forms, and these embodiments are provided only to allow the disclosure of the present disclosure to be complete, and to completely inform those of ordinary skill in the art to which the present disclosure belongs, the scope of the invention, and the present disclosure is only defined by the scope of the claims. Like reference numerals refer to like elements throughout. 
     Referring to  FIG.  1   , an energy storage system  10  includes a case  12 , a battery pack  30  which is disposed inside the case  12 , and in which a plurality of battery cells are disposed, a power converter  35  (PCS) that converts characteristics of electricity so as to charge or discharge the plurality of battery cells disposed in the battery pack  30 , a pump  60  for supplying a cooling fluid to the battery pack  30  or the power converter  35 , a radiator  20  for cooling a cooling fluid flowing from the pump  60 , a fan  18  that forms an air flow from an exterior to the radiator  20 , a first valve  62  for sending the cooling fluid flowing from the pump  60  to the battery pack  30  or to the power converter  35 , and a second valve  64  for sending the cooling fluid flowing from the power converter  35  to the battery pack  30  or to the radiator  20 . 
     The energy storage system  10  may include a cooling fluid pipe (or conduit) which is disposed inside the case  12  and supplies a cooling fluid flowing by the operation of the pump  60  to the battery pack  30  or to the power converter  35 . 
     The case  12  may include a pack storage space  12   a  in which the battery pack  30  is disposed, and a heat dissipation space  12   b  which is formed in the upper side of the pack storage space  12   a , and in which the power converter  35 , the pump  60 , and the radiator  20  are disposed. 
     The case  12  has one side in which an inlet hole  14  through which external air is introduced by the fan  18 , and the other side of the case  12  in which a discharge hole  16  through which the air flowing inside the case  12  is discharged to the outside by the fan  18 . 
     The battery pack  30  is disposed in the pack storage space  12   a  (of the case  12 ). A plurality of battery cells may be connected in series or in parallel inside the battery pack  30 . A plurality of battery packs  30  may be disposed inside the case  12 . Each of the plurality of battery packs  30  may be connected in series with each other. 
     The battery pack  30  may include a plurality of battery cells  33 , a pack housing  32  in which the plurality of battery cells  33  are stored, and a first cooling plate  34 , which is in contact with the plurality of battery cells  33 , and through which a fluid flows. 
     The pack housing  32  forms a space in which the plurality of battery cells  33  are disposed. The pack housing  32  may form a structure for fixing the plurality of battery cells  33  disposed therein. 
     The plurality of battery cells  33  may be disposed to face the same direction inside the pack housing  32 . 
     The first cooling plate  34  may be disposed at (or in) one side of the pack housing  32  or inside the pack housing  32 . The first cooling plate  34  may be disposed between the plurality of battery cells  33  disposed inside the pack housing  32 . The first cooling plate  34  may absorb heat generated in the battery cell  33 . The first cooling plate  34  may form a flow path through which the fluid flows therein. 
     The power converter  35  may include a circuit board  36 , a power conversion device  37  (insulated gate bipolar transistor: IGBT) which is disposed in one side of the circuit board  36  and performs power conversion, and a second cooling plate  38  for cooling the power conversion device  37 . 
     The power conversion device  37  may be an insulated gate bipolar transistor. Such a power conversion device may operate as an A/D converter that converts alternating current of a battery into direct current in order to operate an electronic device requiring direct current by using alternating current, and conversely, may operate as an inverter that converts direct current into alternating current in order to operate an electronic device requiring alternating current by using a storage battery. 
     The second cooling plate  38  may be disposed at one side of the circuit board  36  to absorb heat generated by the power converter  35 . A flow path through which the fluid flows may be formed inside the second cooling plate  38 . 
     The energy storage system  10  may include a pump discharge pipe  40  (or conduit) connecting the pump  60  and the first valve  62 , a power converter inlet pipe  42  (or conduit) connecting the first valve  62  and the power converter  35 , a power converter discharge pipe  44  (or conduit) connecting the power converter  35  and the second valve  64 , a radiator inlet pipe  46  (or conduit) connecting the second valve  64  and the radiator  20 , a first valve discharge pipe  48  (or conduit) for sending the fluid discharged from the first valve  62  to the battery pack  30 , a second valve discharge pipe  54  (or conduit) for sending the fluid discharged from the second valve  64  to the battery pack  30 , a battery pack inlet pipe  50  (or conduit) in which the first valve discharge pipe  48  and the second valve discharge pipe  54  are converged, and which is connected to the battery pack  30 , and a battery pack discharge pipe  52  (or conduit) that connects the battery pack  30  and the radiator  20 . A check valve  55  may be disposed in the second valve discharge pipe  54  to prevent the fluid from flowing backward toward the second valve  64 . The battery pack inlet pipe  50  may couple to the first valve discharge pipe  48  and to the second valve discharge pipe  54 . 
     The first valve  62  may supply (or direct) the fluid flowing from the flow pump  60  to each or both of the power converter  35  and the battery pack  30 . The second valve  64  may supply the fluid flowing from the power converter  35  to the battery pack  30  or to the radiator  20 . The first valve  62  may selectively provide the fluid to the first valve discharge pipe  48  or to the first valve discharge pipe  48 . The second valve  64  may selectively provide the fluid to the radiator inlet pipe  46  or to the second valve discharge pipe  54 . 
     &lt;First valve, Second valve&gt; 
     The first valve  62  and the second valve  64  according to an embodiment of the present disclosure may be described with reference to  FIGS.  2  to  5 B . The contents described in  FIGS.  2  to  5 B  may be applied to both the first valve  62  and/or the second valve  64 . 
     The first valve  62  and the second valve  64  may each separately be a three-way valve having one inlet and two outlets. 
     The valves  62  and  64  may include a distribution pipe  110  (or conduit) that has a flow path through which the fluid flows formed therein and has one inlet  102  and two outlets  104  and  106 , a rotation valve  120  that is rotatably disposed inside the distribution pipe  110  and controls the flow direction of the fluid flowing inside the distribution pipe  110 , and a valve motor  130  which is disposed at one side of the distribution pipe  110  and controls rotation of the rotation valve  120 . 
     The distribution pipe  110  includes an inflow pipe  112  (or conduit) which has the inlet  102  and forms an inflow passage  112   a  therein, a first discharge pipe  114  (or conduit) which has a first outlet  104  and a first discharge passage  114   a  formed therein, a second discharge pipe  116  (or conduit) which has a second outlet  106  and a second discharge passage  116   a  formed therein, and a distribution pipe body  118  (or distribution conduit body) connecting the inflow pipe  112  to the first discharge pipe  114  and the second discharge pipe  116 . 
     The first discharge pipe  114  and the second discharge pipe  116  are each disposed perpendicular to the inflow pipe  112 . The first discharge pipe  114  and the second discharge pipe  116  extend in opposite directions with respect to the distribution pipe body  118 . The first discharge pipe  114  and the second discharge pipe  116  are disposed parallel to each other. The valve motor  130  may be disposed in the opposite direction of the inflow pipe  112  with respect to the distribution pipe body  118 . 
     Inside the distribution pipe body  118 , a sharing chamber  118   a  may be provided for connecting the inflow passage  112   a , the first discharge passage  114   a , and the second discharge passage  116   a . The rotation valve may be rotatably disposed in the sharing chamber  118   a.    
     The rotation valve  120  has a valve inlet  122 , which communicates with the inflow passage  112   a , that is formed in the lower side, and a first valve outlet  124  and a second valve outlet  126  that are formed in a direction perpendicular to the lower side. The first valve outlet  124  and the second valve outlet  126  may be formed in a direction perpendicular to each other. Accordingly, as the rotation valve  120  rotates, the fluid flowing from the inlet  102  may be sent to the first outlet  104  or to the second outlet  106 . 
     The first valve outlet  124  and the second valve outlet  126  are formed in a vertical direction. Accordingly, when the first valve outlet  124  communicates with the first discharge passage  114   a  as shown in  FIGS.  3 A and  3 B , the second discharge passage  116   a  is blocked. Additionally, as shown in  FIGS.  5 A and  5 B , when the second valve outlet  126  communicates with the second discharge passage  116   a , the first discharge passage  114   a  is blocked. 
     As shown in  FIGS.  4 A to  4 B , the first valve outlet  124  may communicate with the first outlet passage  114   a , and the second valve outlet  126  may be disposed to communicate with the second outlet passage  116   a . However, in this example, the opening amount of the first valve outlet  124  and the opening amount of the second valve outlet  126  are reduced, so that the flow rate flowing into the first outlet passage  114   a  and the flow rate into the second outlet passage  116   a  may be reduced. 
     The valve motor  130  may use a DC motor. Accordingly, a rotation range of the rotation valve  120  may be adjusted by changing a pulse applied to the valve motor  130 . 
     Referring to  FIGS.  3 A and  3 B , when a current having a first current value is applied to the valve motor  130 , the first valve outlet  124  and the first outlet passage  114   a  communicate with each other. The first current value may be 0 pulses, for example. When the current having a first current value is applied to the valve motor  130 , the fluid introduced into the inlet  102  may flow to the first outlet  104 . 
     In the first valve  62 , when the current having a first current value is applied to the valve motor  130 , the fluid flowing in from the pump  60  may be supplied (or provided) to the power converter  35 . In the second valve  64 , when the current having a first current value is applied to the valve motor  130 , the fluid flowing in from the power converter  35  may be supplied to the radiator  20 . 
     Referring to  FIGS.  5 A to  5 B , when a current having a second current value is applied to the valve motor  130 , the second valve outlet  126  and the second outlet passage  116   a  communicate with each other. The second current value may be greater than the first current value. The second current value may be 2000 pulses, for example. 
     When the current having a second current value is applied to the valve motor  130 , the fluid introduced into the inlet  102  may flow to the second outlet  106 . 
     In the first valve  62 , when the current having a second current value is applied to the valve motor  130 , the fluid flowing in from the pump  60  may be supplied (or provided) to the battery pack  30 . In the second valve  64 , when the current having a second current value is applied to the valve motor  130 , the fluid flowing in from the power converter  35  may be supplied to the battery pack  30 . 
     Referring to  FIGS.  4 A and  4 B , when the current having a third current value is applied to the valve motor  130 , the first valve outlet  124  and the first discharge passage  114   a  may communicate with each other, and the second valve outlet  126  and the second discharge passage  116   a  may communicate with each other. The third current value may be greater than the first current value and smaller than the second current value. The third current value may be 1000 pulses, for example. 
     When the current having a third current value is applied to the valve motor  130 , the fluid introduced into the inlet  102  may flow to the first outlet  104  and to the second outlet  106 . 
     In the first valve  62 , when the current having a third current value is applied to the valve motor  130 , the fluid flowing in from the pump  60  may be supplied (or provided) to each of the power converter  35  and the battery pack  30 . In the second valve  64 , when the current having a third current value is applied to the valve motor  130 , the fluid flowing in from the power converter  35  may be supplied (or provided) to each of the battery pack  30  and the radiator  20 . 
     A current having a fourth current value that is greater than the first current value and smaller than the third current value may be applied to the valve motor  130 , or a current having a fifth current value that is greater than the third current value and smaller than the second current value may be applied to the valve motor  130 . 
     When the current having a fourth current value is applied to the valve motor  130 , the fluid is discharged to the first outlet  104  and to the second outlet  106 . However, the amount of the fluid discharged to the first outlet  104  may be greater than the amount of the fluid discharged to the second outlet  106 . 
     When the current having a fifth current value is applied to the valve motor  130 , the fluid is discharged to the first outlet  104  and the second outlet  106 . However, the amount of fluid discharged to the first outlet  104  may be smaller than the amount of the fluid discharged to the second outlet  106 . 
     &lt;Controller&gt; 
     The energy storage system  10  may include a controller  70  for controlling operation of the pump  60 , operation of the fan  18 , and opening and closing of the first valve  62  and the second valve  64 . The controller  70  may be a structure that includes hardware. 
     The energy storage system  10  may include a battery pack temperature sensor  72  for detecting the temperature of the battery pack  30 , a power converter temperature sensor  74  (or power conditioning system temperature sensor) for detecting the temperature of the power converter  35 , and a fluid temperature sensor  76  for detecting the temperature of the fluid discharged from the radiator  20  (or at the radiator). 
     The controller  70  may cool the battery pack  30  or the power converter  35  by adjusting the first valve  62  and the second valve  64  based on the temperature detected from the battery pack temperature sensor  72 , the power converter temperature sensor  74 , and/or the fluid temperature sensor  76 . The controller  70  may adjust the first valve  62  and the second valve  64  to adjust an amount of fluid discharged from the first valve  62  or the second valve  64  based on an opening degree of the corresponding valve. 
     The controller  70  may adjust the rotation speed of the fan  18  or the pump  60  based on the temperature detected from the battery pack temperature sensor  72 , the power converter temperature sensor  74 , and/or the fluid temperature sensor  76 . 
     &lt;Operation&gt; 
     An operation of the energy storage system  10  may be described with reference to  FIGS.  7  to  10   . 
     The energy storage system  10  may be operated in a simultaneous cooling mode for simultaneously cooling the battery pack  30  and the power converter  35 , a combined mode for cooling the power converter  35  and heating the battery pack  30 , a battery pack cooling mode for cooling only the battery pack  30 , and/or a power converter cooling mode for cooling only the power converter  35 . 
     Referring to  FIG.  7   , while in the simultaneous cooling mode, the fluid cooled in the radiator  20  may flow to each of the power converter  35  and the battery pack  30 . That is, the first valve  62  discharges the fluid flowing in from the pump  60  to each of the power converter  35  and the battery pack  30 . 
     At this time, when the temperature of the fluid supplied to the first valve  62  detected from the fluid temperature sensor  76  exceeds a first set temperature, the controller  70  may increase the rotation speed of the fan  18 , and/or may operate the pump  60  to increase the flow rate of the fluid discharged from the pump  60 . 
     Additionally, the controller  70  may compare the temperature detected from the battery pack temperature sensor  72  and the temperature detected from the power converter temperature sensor  74 , and adjust the first valve  62  to increase the flow rate of the fluid toward the component (i.e., the battery pack or the power converter) having a higher temperature. 
     Referring to  FIG.  8   , in the combined mode, the fluid flowing from the pump  60  may sequentially flow to the power converter  35  and to the battery pack  30 . Accordingly, the power converter  35  may be cooled by the fluid, and the fluid that has absorbed heat from the power converter  35  may be supplied (or provided) to the battery pack  30  to preheat the battery pack  30 . 
     At this time, the controller  70  may prevent the fan  18  from rotating, so that the fluid may lose (or reduce) heat from the battery pack  30  and the fluid can receive heat from the power converter  35 . 
     Referring to  FIG.  9   , while in the battery pack cooling mode, the fluid discharged from the pump  60  is supplied (or provided) only to the battery pack  30  by adjusting the first valve  62 . Accordingly, the fluid flowing from the pump  60  flows to the first valve  62 , the battery pack  30 , and the radiator  20 . 
     Referring to  FIG.  10   , while in the power converter cooling mode, the fluid flowing through the pump  60  may pass only through the power converter  35  and flow to the radiator  20  by adjusting the first valve  62  and the second valve  64 . 
     The first valve  62  discharges the fluid flowing in from the pump  60  toward the power converter  35 . The second valve  64  discharges the fluid flowing in from the power converter  35  to the radiator  20 . 
     According to the energy storage system of the present disclosure, there are one or more of the following effects. First, it has an advantage of providing an integrated fluid that can be used in various environments and climates by using a single pump and two three-way valves. Additionally, since a single pump is used, there is an advantage that power reduction effect can be expected. Second, there is a structural advantage in that the flow drift can be prevented compared to using a four-way valve because it can be designed to use a three-way valve. 
     The present disclosure has been made in view of the above problems, and provides an energy storage system capable of cooling and heating a battery by using a single pump, in a structure for cooling a battery pack by water cooling. 
     The present disclosure further provides an energy storage system capable of adjusting a flow by a part for supplying a fluid. 
     In accordance with an aspect of the present disclosure, an energy storage system includes: a battery pack in which a plurality of battery cells electrically connected are disposed; a power converter which converts characteristic of electricity so as to charge or discharge the plurality of battery cells disposed in the battery pack; a pump which supplies a fluid to the battery pack or the power converter; a radiator which heat-exchanges the fluid flowing by the pump with air; a first valve which sends a fluid discharged from the pump to the power converter or the battery pack; and a second valve which sends the fluid discharged from the power converter to the battery pack or the radiator, so that various modes of operation can be performed through one pump and two valves. 
     The energy storage system further includes: a power converter inlet pipe which connects the first valve and the power converter; a radiator inlet pipe which sends the fluid discharged from the second valve to the radiator; a first valve discharge pipe which sends the fluid discharged from the first valve to the battery pack; a second valve discharge pipe which sends the fluid discharged from the second valve to the battery pack; and a battery pack inlet pipe in which the first valve discharge pipe and the second valve discharge pipe are converged, and which is connected to the battery pack, so that the fluid discharged from the second valve may be flowed in combination with the fluid discharged from the first valve or may be flowed separately. 
     A check valve is disposed in the second valve discharge pipe so as to prevent the fluid from flowing backward in a direction of the second valve. 
     The first valve sends the fluid flowing in from the pump to one of the power converter and the battery pack, or to each of the power converter and the battery pack, so that each of the power converter and the battery pack can be cooled individually, or the power converter and the battery pack can be cooled simultaneously. 
     The energy storage system further includes: a controller which controls an operation of the first valve and the second valve; a battery pack temperature sensor which detects a temperature of the battery pack; and a power converter temperature sensor which detects a temperature of the power converter, wherein the controller adjusts a flow rate of the fluid supplied to the battery pack and the power converter, based on the temperature detected by the battery pack temperature sensor and the temperature detected by the power converter temperature sensor, so that the flow rate of the fluid can be adjusted for a place where cooling is relatively more required. 
     The energy storage system further includes: a fluid temperature sensor which detects a temperature of the fluid discharged from the radiator; and a fan which supplies an external air to the radiator, wherein when the temperature of the fluid detected by the fluid temperature sensor exceeds a first set temperature, the controller operates the pump to increase a rotation speed of the fan and to increase the flow rate of the fluid supplied to the radiator, thereby quickly accomplishing the temperature control of the power converter or the battery pack. 
     In a simultaneous cooling mode for simultaneously cooling the power converter and the battery pack, the first valve discharges the fluid flowing in from the pump to each of the power converter and the battery pack, so that the battery pack and the power converter can be cooled simultaneously. 
     In the simultaneous cooling mode, the controller controls an operation of the pump to increase the flow rate of the fluid discharged from the pump, thereby increasing the cooling efficiency of each of the battery pack and the power converter. 
     In the simultaneous cooling mode, the controller compares the temperature detected from the battery pack temperature sensor and the temperature detected from the power converter temperature sensor, and adjust the first valve to increase the flow rate of the fluid toward a place having a higher temperature among the battery pack and the power converter, so that the flow rate of the fluid can be adjusted for a place where cooling is relatively more required. 
     In a combined mode for cooling the power converter and heating the battery pack, the controller adjusts the first valve and the second valve so that the fluid flowing by the pump sequentially flows to the power converter and the battery pack, thereby cooling the power converter and heating the battery pack. 
     In the combined mode, the controller adjusts the first valve so that the fluid supplied from the pump is supplied to the power converter, and adjusts the second valve so that the fluid supplied from the power converter is supplied to the battery pack. 
     The energy storage system further includes a fan that supplies an external air to the radiator, wherein in the combined mode, the controller stops an operation of the fan, thereby eliminating power loss in a situation where heat dissipation condition is not required. 
     The first valve or the second valve uses a three-way valve having one inlet and two outlets, so that one pump and two three-way valves may be provided. 
     Each of the first valve and the second valve includes: a distribution pipe which has a flow path, which is formed therein, through which the fluid flows and has a first outlet and a second outlet, which are opened in a different direction from the inlet, that are formed in one side; a rotation valve which is rotatably disposed inside the distribution pipe, and adjusts a flow direction of the fluid flowing inside the distribution pipe; and a valve motor which is disposed in one side of the distribution pipe, and rotates the rotation valve, wherein the fluid flowing from the inlet is transmitted to the first outlet or the second outlet, as the rotation valve rotates. 
     The distribution pipe includes: an inlet pipe which has the inlet, and forms an inflow passage therein; a first discharge pipe which has the first outlet and a first discharge passage formed therein, a second discharge pipe which has the second outlet and a second discharge passage formed therein, and a distribution pipe body which communicates the inflow passage with the first discharge pipe or the second discharge pipe, wherein each of the first discharge pipe and the second discharge pipe is disposed perpendicular to the inlet pipe, and the rotation valve has a valve inlet, which communicates with the inflow passage, that is formed in a lower side, and a first valve outlet and a second valve outlet that are formed in a direction perpendicular to the lower side, wherein the valve motor adjusts an opening range of each of the first valve outlet and the second valve outlet, thereby adjusting the flow rate of the fluid discharged to each outlet. 
     It will be understood that when an element or layer is referred to as being “on” another element or layer, the element or layer can be directly on another element or layer or intervening elements or layers. In contrast, when an element is referred to as being “directly on” another element or layer, there are no intervening elements or layers present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     It will be understood that, although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section could be termed a second element, component, region, layer or section without departing from the teachings of the present invention. 
     Spatially relative terms, such as “lower”, “upper” and the like, may be used herein for ease of description to describe the relationship of one element or feature to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “lower” relative to other elements or features would then be oriented “upper” relative to the other elements or features. Thus, the exemplary term “lower” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     Embodiments are described herein with reference to cross-section illustrations that are schematic illustrations of idealized embodiments (and intermediate structures). As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to affect such feature, structure, or characteristic in connection with other ones of the embodiments. 
     Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.