Abstract:
A method of protecting a battery is provided in a vehicle having a battery that selectively supplies electric power for starting an engine of the vehicle and that selectively supplies electric power to a plurality of electric loads of the vehicle. The method includes: obtaining a temperature; determining a state of charge (SOC) of the battery; determining a first threshold based on the obtained temperature; determining a second threshold based on the obtained temperature, the second threshold being different than the first threshold; taking a first remedial action if the SOC is below the first determined threshold; and taking a second remedial action if the SOC is below the second determined threshold, the second remedial action being different from the first remedial action.

Description:
BACKGROUND 
     The present specification relates generally to the automotive arts. More specifically, the present specification relates to a battery protection system and/or method. Particular application is found in connection with an electrical system of a motor vehicle (e.g., an automobile or other vehicle driven by an internal combustion engine), and the specification makes particular reference thereto. However, it is to be appreciated that aspects of the present subject matter are also amenable to other like applications. 
     As is known in the art, many automotive vehicles generally include an internal combustion or other like engine that drives the vehicle. A modern vehicle is also typically provisioned with an electrical system including: (i) a battery which provides a source of electric power for starting the vehicle&#39;s engine; and, (ii) one or more electric circuits or loads (e.g., headlights, clocks, electrically powered adjustable components such as seats, mirrors or steering columns, interior cabin lights, electric heaters for seats, mirrors, windows or the like, radios and/or other entertainment systems, electronic memories for recording radio station presets and/or user preferred seat and/or mirror positions, electronic navigation systems, etc.) that may also be selectively powered by the vehicle&#39;s battery. The trend of providing more electronic features and/or devices in a vehicle typically results in addition burden on the vehicle&#39;s battery and thus it become even more prudent to pay meaningful consideration to maintaining the health of the battery. 
     To maintain the general health of a battery in good condition and/or to retain sufficient charge in the battery for starting the vehicle&#39;s engine, it is generally advantageous to protect a vehicle&#39;s battery from excessive discharge. As can be appreciated, however, some of the foregoing examples of electronic features and/or devices that tax the vehicle&#39;s battery are normally of the type that cannot be manually isolated from the vehicle&#39;s battery by the driver or other vehicle occupant. Additionally, electrical components and/or devices of a vehicle can be inadvertently left on when their use is no longer desired and/or the vehicle is unattended. Clearly, this can further stress a vehicle&#39;s battery unduly. 
     Accordingly, a new and improved system and/or method for protecting a vehicle battery from excessive discharge is disclosed that overcomes the above-referenced problems and others. 
     SUMMARY 
     According to one aspect, a method of protecting a battery is provided in a vehicle having a battery that selectively supplies electric power for starting an engine of the vehicle and that selectively supplies electric power to a plurality of electric loads of the vehicle. The method includes: obtaining a temperature; determining a state of charge (SOC) of the battery; determining a first threshold based on the obtained temperature; determining a second threshold based on the obtained temperature, the second threshold being different than the first threshold; taking a first remedial action if the SOC is below the first determined threshold; and taking a second remedial action if the SOC is below the second determined threshold, the second remedial action being different from the first remedial action. 
     According to another aspect, a system for protecting a battery is provided in a vehicle having a battery that selectively supplies electric power for starting an engine of the vehicle and that selectively supplies electric power to a plurality of electric loads of the vehicle. The battery protection system includes: temperature sensing means for obtaining a temperature; battery sensing means for determining a state of charge (SOC) of the battery; threshold determining means for determining a first threshold based on the temperature obtained by the temperature sensing means and a second threshold based on the temperature obtained by the temperature sensing means, the second threshold being different than the first threshold; and remedial action means for taking a first remedial action if the SOC is below the first determined threshold and a second remedial action if the SOC is below the second determined threshold, the second remedial action being different from the first remedial action. 
     According to still another aspect, a battery protection system is provided in a vehicle having a battery that selectively supplies electric power for starting an engine of the vehicle and that selectively supplies electric power to a plurality of electric loads of the vehicle. The battery protection system includes: a first sensor that measures at least one of a temperature of the battery, a temperature of the vehicle&#39;s engine and an ambient temperature; a second sensor that detects a state of charge (SOC) of the battery; and a controller that: (i) determines a plurality of different thresholds based upon the measurement from the first sensor; (ii) compares the SOC detected by the second sensor to the plurality of thresholds; and (iii) selectively triggers a plurality or different remedial actions in response to comparing the detected SOC to the plurality of different thresholds. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram showing an exemplary battery protection system of a vehicle suitable for practicing aspects of the present disclosed subject matter. 
         FIG. 2  is a flow chart showing an exemplary process for protecting a battery from excessive discharge in accordance with aspects of the present disclosed subject matter. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings, wherein the showings are for purposes of illustrating one or more exemplary embodiments,  FIG. 1  shows a schematic diagram of a battery protection system for a vehicle  10 , e.g., such an automobile or other similar automotive vehicle. Suitably, the vehicle  10  includes an engine  12  (e.g., an internal combustion engine or the like) that drives the vehicle  10 . The vehicle  10  is also provisioned with an electrical system including: a battery  14  which suitably provides a source of electric power for starting the engine  12  of the vehicle  10 ; and, one or more electric circuits or loads that may also be selectively powered by the vehicle&#39;s battery  14 . For example, the loads may include: headlights, clocks, electrically powered adjustable components such as seats, mirrors or steering columns, interior cabin lights, electric heaters for seats, mirrors, windows or the like, radios and/or other entertainment systems, electronic memories for recording radio station presets and/or user preferred seat and/or mirror positions, electronic navigation systems, etc. In particular, there are two loads illustrated in  FIG. 1 , namely, a first load  16  and a second load  18 . Optionally, the first load  16  represents, e.g., interior cabin lights for the vehicle  10 , while the second load  18  represents, e.g., backup electronic functions—also commonly referred to as “+B” functions. Suitably, the battery is a nominal 12 volt (v) battery of the type commonly employed in automobiles or may be any other type of battery, e.g., typically used in automotive applications. 
     According to one exemplary embodiment, the vehicle  10  is further equipped or otherwise provisioned with an ignition system for selectively starting and stopping the engine  12  of the vehicle  10 . As illustrated in  FIG. 1 , the ignition system suitably includes an ignition switch  20  or other like device use in conjunction with a key  22 , e.g., which can be a conventional cut key, an electronic key or the like. In the usual fashion, the key  22  is optionally manipulated to selectively place the ignition switch  20  in either of two or more positions or states, namely, (i) a key ON position or state, or (ii) a key OFF position or state. 
     As shown in  FIG. 1 , the battery protection system includes one or more devices such as relays  36  and  38  or other suitable switches or the like that are arranged between the battery  14  and the loads  16  and  18 . Under the control of a controller  30  which is also part of the battery protection system, the relays  36  and  38  are selectively opened and closed. In their open states, each relay disconnects or otherwise isolates its respective the load from the battery  14  so that current or electric power from the battery  14  is cut-off to the corresponding load. That is to say, in practice, when the controller  30  detects one or more selected conditions or otherwise determines that certain criteria are met, the controller  30  sends a suitable control signal to the appropriate relay  36  and/or  38 . In response to the control signal, the respective relay  36  and/or  38  is tripped or otherwise set to its open state thereby cutting-off the delivery of electric power or current from the battery  14  to the corresponding load  16  and/or  18 . Alternately, in their normally closed states, the respective relays  36  and  38  operatively connect their corresponding loads  16  and/or  18  to the battery  14  so that electric power and/or current can be delivered from the battery  14  to the respective loads  16  and/or  18 . 
     In the illustrated embodiment, the battery protection system also suitably includes: a state of charge (SOC) sensor  32  that senses, detects and/or otherwise determines a SOC or condition of the battery  14 ; a temperature sensor  34  that senses, detects and/or otherwise determines a temperature of the engine  12 , the battery  14  and/or the surrounding ambient temperature; and, a display  40  or other suitable visual, audible or humanly perceivable warning indicator. Suitably, the controller  30  regulates or otherwise controls operation of the relays  36  and  38  and/or the display  40  in response to the SOC or condition of the battery  14  as detected by the sensor  32 . As shown, the SOC or condition of the battery  14  is obtained by the controller  30  from the sensor  32  which is electrically and/or otherwise operatively connected to the battery  14  so as to sense and/or otherwise detect the SOC and/or condition of the battery  14 . 
     More specifically, for example, the controller  30  receives a signal representative of a condition or SOC of the battery  14  from the sensor  32 . In the illustrated embodiment, the sensor  32  is electrically connected to the battery  14  for determining the SOC and/or condition of the battery  14  and generating an SOC signal representative thereof to send to the controller  30 . The SOC signal can be one or more signals that indicate the condition or SOC of the battery  14 . The condition can be a value indicating the charge remaining in the battery  14  relative to a scale ranging between a low end where no charge remains in the battery  14  and a high end where the battery  14  is fully charged. In one suitable embodiment, the SOC signal indicates the condition of the battery  14  as related to its overall charge capacity (i.e., a value or percentage of a maximum SOC of the battery  14 ). In another exemplary embodiment, the SOC signal indicates the percentage of maximum electrical energy output of the battery  14 . In either event, suitably the sensor  32  measures or otherwise detects any one or more of a variety of different factors and/or parameters from which the battery&#39;s SOC is calculated or otherwise determined. These factors or parameters suitably include but are not limited to, the battery voltage, battery current, charge balance, etc. In practice, any of a variety of well know or otherwise appropriate methods and/or algorithms may optionally be used to calculate or determine the SOC from the respective parameters measured or otherwise obtained by the sensor  32 . 
     In addition to the SOC signal received from the SOC sensor  32 , the controller  30  also receives a temperature signal or measurement obtained from the temperature sensor  34 . Suitably, the controller  30  uses this temperature signal or measurement to calculate, adjust and/or otherwise determine the values for a plurality of different thresholds. Moreover, the controller  30  also optionally monitors and/or otherwise receives a signal indicative of the state of the ignition switch  20 , i.e., ON or OFF. In turn, the controller  30  selectively takes one or more appropriate remedial actions to protect the battery  14  from excessive discharge by comparing the SOC obtained from the SOC sensor  32  to the respective determined thresholds. For example, suitable remedial actions include: (i) selectively disconnecting one or more of the loads  16  and/or  18  from the battery  14  or otherwise cutting-off power from the battery  14  to one or more of the loads  16  and/or  18 , e.g., via appropriate control of the respective relays  36  and/or  38 ; and/or, (ii) selectively output via the display  40  a suitable warning indication regarding the SOC or condition of the battery and/or other indication of the remedial actions taken by the controller  30 . 
     In one suitable embodiment, each threshold value is calculated as a corresponding function of the measured or otherwise obtained temperature. For example, to determine each individual threshold the controller  30  optionally executes the equation TH n =f n (TEMP), where TH n  represents the nth threshold and f n (TEMP) represents a function of the obtained temperature (TEMP) for the nth threshold. Alternately, each threshold may be given or assigned some preset or otherwise determined value in the controller  30  and the obtained temperature is used by the controller  30  to select or determine an offset amount or otherwise adjust each preset threshold value by some set or otherwise determined amount. Suitably, for any given temperature, the offset or adjustment amount may be the same for each threshold or it may vary between different thresholds. In yet another example, a look-up table (LUT) or the like may be provisioned in the controller  30  which relates nominal threshold values and temperature. Accordingly, to determine an actual threshold to which the SOC will be compared by the controller  30 , the controller  30  accesses the LUT by cross-referencing a nominal threshold value with the obtained temperature, thereby retrieving the corresponding entry in the LUT to be used as the actual threshold value. 
     With reference now to  FIG. 2 , there is shown an exemplary process  100  for protecting the battery  14  from excessive discharge. In the illustrated example, three thresholds (namely, TH 1 , TH 2  and TH 3 ) that are calculated or otherwise determined based upon the measured or otherwise obtained temperature from the temperature sensor  34  are employed to selectively trigger corresponding remedial actions by the controller  30  based upon a comparison of the SOC received from the SOC sensor  32  to the respective thresholds. It is to be appreciated, however, that in practice more or less thresholds and/or corresponding remedial actions may in fact be employed as desired for a specific application and/or implementation. 
     In the illustrated example, at step  102 , the controller  30  obtains the temperature signal or measurement from the sensor  34  and the SOC signal or measurement from the sensor  32 . At decision step  104 , the state of the ignition switch  20  is also obtained by the controller  30  and it is determined if the state of the ignition switch  20  is ON or OFF. If the state of the ignition switch  20  is determined to be ON, then the process  100  continues to step  118 , otherwise if the state of the ignition switch is determined to be OFF, then the process  100  branches to step  106 . 
     At step  106 , the controller  30  calculates (e.g., from a function f 1 ) and/or otherwise determines a value for a first threshold (TH 1 ) based on the temperature (TEMP) obtained in step  102 . In turn, at step  108 , the controller  30  compares the SOC obtained in step  102  to the threshold TH 1  determined in step  106 . If the SOC has met the threshold (i.e., SOC≦TH 1 ), then the process  100  branches to step  110 . At step  110 , the controller  30  turns off the power supply from the battery  14  to the load  16 , e.g., via suitable control of the relay  36 . Optionally, at this point the controller  30  also signals and/or otherwise controls the display  40  to output a corresponding message or other indication of the remedial action being taken, e.g., “Due to Insufficient Battery Level, Your Vehicle&#39;s Battery Management System has Forcefully Turned-Off the Interior Lighting.” Following step  110 , the process  100  continues to step  112 . Alternately, if at decision step  108 , it is determined that the SOC has not met the threshold (i.e., SOC&gt;TH 1 ), then the process  100  skips step  110  and proceeds directly to step  112 . 
     At step  112 , the controller  30  calculates (e.g., from a function f 2 ) and/or otherwise determines a value for a second threshold (TH 2 ) based on the temperature (TEMP) obtained in step  102 . In turn, at step  114 , the controller  30  compares the SOC obtained in step  102  to the threshold TH 2  determined in step  112 . If the SOC has met the threshold (i.e., SOC≦TH 2 ), then the process  100  branches to step  116 . At step  116 , the controller  30  turns off the power supply from the battery  14  to the load  18 , e.g., via suitable control of the relay  38 . Optionally, at this point the controller  30  also signals and/or otherwise controls the display  40  to output a corresponding message or other indication of the remedial action being taken, e.g., “Due to Insufficient Battery Level, Your Vehicle&#39;s Battery Management System has Forcefully Turned-Off the +B Power Supply.” Following step  116 , the process  100  suitably end. Alternately, if at decision step  114 , it is determined that the SOC has not met the threshold (i.e., SOC&gt;TH 2 ), then the process  100  skips step  116  and proceeds directly to the end of the process  100 . 
     Returning attention now to decision step  104 , if it is determined that the ignition switch  20  is in the ON state, then the process  100  continues to step  118 . At step  118 , the controller  30  calculates (e.g., from a function f 3 ) and/or otherwise determines a value for a third threshold (TH 3 ) based on the temperature (TEMP) obtained in step  102 . In turn, at step  120 , the controller  30  compares the SOC obtained in step  102  to the threshold TH 3  determined in step  118 . If the SOC has met the threshold (i.e., SOC≦TH 3 ), then the process  100  branches to step  122 . At step  122 , the controller  30  signals and/or otherwise controls the display  40  to output an appropriate warning message or other indication regarding the SOC or condition of the battery  14 , e.g., “BATTERY CHARGE LOW—Please Start Engine to Recharge Battery or Turn Vehicle Off to Conserve Battery Condition.” Alternately, if at decision step  120 , it is determined that the SOC has not met the threshold (i.e., SOC&gt;TH 3 ), then the process  100  skips step  122  and proceeds directly to the end of the process  100 . 
     While one or more of the foregoing embodiments have been described with reference to the battery&#39;s SOC, it is to be appreciated that SOC is merely an exemplary parameter that sensed, measured and/or otherwise determined and accordingly used as a basis for adjusting the respective thresholds (e.g., TH 1 , TH 2  and TH 3 ). More generally and/or in alternate embodiments, other parameters indicative of and/or related to the battery&#39;s state of function (SOF) may similarly be obtained (i.e., sensed, measure and/or otherwise determined) and accordingly used as a basis for adjusting the respective thresholds. In this regard, examples of the battery&#39;s SOF include not only the battery&#39;s SOC but also the battery&#39;s cranking voltage, the internal resistance of the battery, the battery&#39;s reserve capacity, the cold cranking amperes (CCA) of the battery, the battery&#39;s health and the like. Accordingly, it is intended that the terms and/or parameters SOC and SOF when used herein may optionally be interchanged where appropriate to achieve various alternate embodiments suitable for particular desired applications. 
     In any event, it is to be appreciated that in connection with the particular exemplary embodiments presented herein certain structural and/or function features are described as being incorporated in defined elements and/or components. However, it is contemplated that these features may, to the same or similar benefit, also likewise be incorporated in common elements and/or components where appropriate. For example, the sensor  32  and controller  30  may suitably be integrated together. It is also to be appreciated that different aspects of the exemplary embodiments may be selectively employed as appropriate to achieve other alternate embodiments suited for desired applications, the other alternate embodiments thereby realizing the respective advantages of the aspects incorporated therein. 
     It is also to be appreciated that particular elements or components described herein may have their functionality suitably implemented via hardware, software, firmware or a combination thereof. For example, the controller  30  and/or sensor  32  may be implemented as appropriate hardware circuits or alternately as microprocessors programmed to implement their respective functions. Additionally, it is to be appreciated that certain elements described herein as incorporated together may under suitable circumstances be stand-alone elements or otherwise divided. Similarly, a plurality of particular functions described as being carried out by one particular element may be carried out by a plurality of distinct elements acting independently to carry out individual functions, or certain individual functions may be split-up and carried out by a plurality of distinct elements acting in concert. Alternately, some elements or components otherwise described and/or shown herein as distinct from one another may be physically or functionally combined where appropriate. 
     In short, it will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.