Patent Publication Number: US-2016231390-A1

Title: Battery abnormality indication apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is based on and claims the benefit of priority of Japanese Priority Application No. 2015-023556, filed on Feb. 9, 2015, the entire contents of which are hereby incorporated herein by reference. 
     BACKGROUND 
     1. Field 
     The present disclosure relates to a battery abnormality indication apparatus. 
     2. Description of the Related Art 
     In the related art, a technology is known where, based on an internal resistance of a battery, it is determined whether the battery has abnormality, and abnormality is indicated (for example, see Japanese Laid-Open Patent Application No. 60-140163). 
     SUMMARY 
     According to one aspect of the present disclosure, a battery abnormality indication apparatus includes a measurement sensor that measures a state of a battery; an electronic control unit that determines, based on the state of the battery acquired from the measurement sensor, whether the battery has abnormality; and an indicator that indicates abnormality of the battery when the electronic control unit determines that the battery has abnormality. When the electronic control unit determines that a used amount of the battery is less than a predetermined amount, the indicator indicates a first abnormality indication showing a fault of the battery, and, when the electronic control unit determines that the used amount of the battery is greater than or equal to the predetermined amount, the indicator indicates a second abnormality indication showing degradation of the battery. 
     Other objects, features and advantages of the present disclosure will become more apparent from the following detailed description when read in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram illustrating one example of a configuration of a battery abnormality indication apparatus; 
         FIG. 2  is a flowchart illustrating one example of operations of the battery abnormality indication apparatus; 
         FIG. 3  is a flowchart illustrating another example of operations of the battery abnormality indication apparatus; 
         FIG. 4  is a flowchart illustrating yet another example of operations of the battery abnormality indication apparatus; 
         FIG. 5  illustrates one example of a temporal change in an internal resistance; 
         FIG. 6  illustrates one example of relationships between an estimated value of a battery voltage and a charged amount; and 
         FIG. 7  illustrates one example of relationships between a battery voltage and a charged ratio. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     For the purpose of convenience, the description of the above-mentioned related art will be continued first. 
     In the related art, abnormality is indicated in the same manner between a case where a battery degrades due to an increase in the used amount (for example, aged deterioration) and a case where a fault occurs in the battery such that an electrode column is damaged, or so. Therefore, a user cannot understand whether abnormality is indicated due to degradation in the battery or a fault of the battery. 
     An object of the embodiments is to provide a battery abnormality indication apparatus capable of showing a user whether abnormality is indicated due to degradation or a fault of a battery. 
     Below, the embodiments will be described with reference to the drawings. 
       FIG. 1  is a block diagram illustrating one example of a configuration of a battery abnormality indication apparatus  101  according to one embodiment. The battery abnormality indication apparatus  101  is, for example, an apparatus mounted in a vehicle such as an automobile, and has a function of indicating abnormality of a battery  10  mounted in the vehicle. The battery abnormality indication apparatus  101  includes, for example, the battery  10 , a measurement sensor or measurement part  20 , a control part  30 , and an indicator  40 . 
     The battery  10  is one example of a secondary battery capable of supplying power to a load installed in the vehicle (for example, the measurement part  20 , the control part  30 , the indicator  40 , and so forth). The battery  10  is charged by a power generation device, for example, an alternator  11 . The alternator  11  is a generator generating power as a result of being rotated in synchronization with, for example, an engine  12  that is a power source of the vehicle. The battery  10  is a source to supply power to start the engine  12 . As a specific example of the battery  10 , a lead battery can be cited. 
     An engine control part  13  is one example of an engine control part for starting the engine  12 . As a specific example of the engine control part  13 , an engine ECU starting the engine  12  in response to an ignition switch  14  being turned on, an idling-stop ECU controlling idling stop of the engine  12 , or so, can be cited. 
     The measurement part  20  is one example of a battery state measurement part measuring a state of the battery  10  (the battery state). The measurement part  20  has, for example, a current measurement part  21 , a temperature measurement part  22 , and a voltage measurement part  23 . As specific examples of the battery state, the battery current, the battery temperature, the battery voltage, and so forth, can be cited. The engine control part  13  can be included in the measurement part  20 . 
     The current measurement part  21  is one example of a current measurement part measuring the current flowing through the battery  10  (the battery current). The current measurement part  21  is, for example, a current sensor measuring the charging current or the discharging current flowing through the battery  10 . 
     The temperature measurement part  22  is one example of a temperature measurement part measuring the temperature of the battery  10  itself or the ambient temperature of the battery  10  (the battery temperature). The temperature measurement part  22  is, for example, a temperature sensor measuring the battery temperature. 
     The voltage measurement part  23  is one example of a voltage measurement part measuring the voltage of the battery  10  (the battery voltage). The voltage measurement part  23  is, for example, a voltage sensor measuring the battery voltage. 
     The control part  30  is one example of a control part determining whether the battery  10  has abnormality based on the battery state acquired from of the measurement part  20 . The control part  30  is, for example, an Electronic Control Unit (ECU) having a detection part  31  and an abnormality determination part  36 . The respective functions of the detection part  31  and the abnormality determination part  36  are implemented by, for example, a microcomputer having a Central Processing Unit (CPU). 
     The detection part  31  is one example of a battery state detection sensor detecting a battery state other than the battery current, the battery temperature, and the battery voltage. As specific examples of “a battery state other than the battery current, the battery temperature, and the battery voltage”, the used amount, the charged ratio, the internal resistance, the degradation degree, and so forth, of the battery  10 , for example, can be cited (which will be described later in detail). 
     The detection part  31  has, for example, a used amount measurement part  32 , a charged ratio calculation part  33 , an internal resistance calculation part  34 , and a degradation determination part  35 . 
     The used amount measurement part  32  is one example of a measurement sensor measuring the used amount of the battery  10  based on the battery state acquired from at least one of the measurement part  20  and the engine control part  13 . When the battery  10  is replaced, the used amount measurement part  32  resets the used amount of the battery  10 , and starts measuring the used amount of the battery  10  that has been thus replaced with. 
     As a specific example of the used amount of the battery  10 , the accumulated value of the charged and discharged amount of the battery  10 , the number of start times of the engine  12  started with power supplied by the battery  10 , the used period of time of the battery  10 , or so, can be cited. 
     The used amount measurement part  32  measures the accumulated value of the charged and discharged amount of the battery  10  by, for example, accumulating the current value of the battery current acquired by the current measurement part  21  from when manufacturing the vehicle is completed (for example, from when the battery  10  is first mounted). The accumulated value of the charged and discharged amount of the battery  10  is a value acquired from accumulating the absolute value of the current value of the charging current and the absolute value of the current value of the discharging current of the battery  10 . 
     It is also possible that the used amount measurement part  32  counts the number of start times of the engine  12  by, for example, acquiring starting information of the engine  12  from the engine control part  13 . It is also possible that the used amount measurement part  32  measures the used period of time of the battery  10  by, for example, measuring the elapsed time from when manufacturing the vehicle is completed, for example, from when the battery  10  is mounted in the vehicle. 
     The charged ratio calculation part  33  is one example of a charged ratio calculation part calculating the charged ratio of the battery  10  based on the measurement result of the battery state acquired from the measurement part  20 . The charged ratio calculation part  33  calculates, for example, a State of Charge (SOC) indicating the charged ratio of the battery  10 . “SOC” is a value defined by, for example, “(remaining capacity of battery  10  (A·s))/(fully charged capacity of the battery  10  (A·s))×100(%)”. 
     The charged ratio calculation part  33  calculates the charged ratio based on the battery voltage measured by the voltage measurement part  23  in a state where, for example, the alternator  11  is not operated, corrects the thus calculated charged ratio using at least one of the battery temperature and the battery current, and thus, calculates the accurate charged ratio. Note that the actual method of calculating the charged ratio of the battery  10  by the charged ratio calculation part  33  can be any method. 
     The internal resistance calculation part  34  is one example of an internal resistance calculation part calculating the internal resistance of the battery  10  based on the measurement result of the battery state acquired from the measurement part  20 . The internal resistance calculation part  34  calculates the internal resistance of the battery  10  by, for example, dividing the battery voltage measured by the voltage measurement part  23  by the battery current measured by the current measurement part  21 . It is possible that the internal resistance calculation part  34  corrects the calculated internal resistance using at least one of the charged ratio of the battery  10  and the battery temperature, and thus, calculates the accurate internal resistance. Note that the actual method of calculating the internal resistance of the battery  10  by the internal resistance calculation part  34  can be any method. 
     The degradation determination part  35  is one example of a degradation determination part determining the degradation degree of the battery  10 . An increase in the degradation degree calculated by the degradation determination part  35  indicates that the degradation of the battery  10  has become worse. The actual method of calculating the degradation degree by the degradation determination part  35  can be any method. One example will be described later. 
     The abnormality determination part  36  is one example of an abnormality determination part determining whether the battery  10  has abnormality based on the battery state acquired from at least one of the measurement part  20  and the detection part  31 . The abnormality determination part  36  determines that the battery  10  has abnormality if the battery state acquired by at least one of the measurement part  20  and the detection part  31  satisfies a predetermined abnormality determination condition. 
     The abnormality determination part  36  determines that the battery  10  has abnormality if, for example, the voltage measurement part  23  measures that the minimum value of the battery voltage acquired when the engine  12  is being started is less than or equal to a predetermined starting performance determination threshold Vth. The “starting performance determination threshold Vth” is a threshold for determining whether performance (starting performance of the battery  10 ) of the battery  10  for starting the engine  12  is degraded, and, is one example of an abnormality determination condition for determining whether the battery  10  has abnormality. 
     As a specific example of a variation in the internal resistance, the difference in the internal resistance between before and after a change, the change rate in the internal resistance between before and after a change (i.e., the increase rate or the decrease rate), or such, can be cited. 
     The indicator  40  is one example of an indicator that indicates abnormality of the battery  10  if the battery  10  is determined to have abnormality by the abnormality determination part  36  of the control part  30 . As a specific example of the indicator  40 , a display device, a lamp, or such, indicating abnormality information showing abnormality of the battery  10  in such a manner as to be visible by a user of the vehicle such as an occupant thereof, can be cited. 
       FIG. 2  is a flowchart illustrating one example of operations of the battery abnormality indication apparatus  101 , and illustrating one example of a battery abnormality indication method carried out by the control part  30  of the battery abnormality indication apparatus  101 . 
     In step S 10 , the abnormality determination part  36  determines whether the battery  10  has abnormality based on the battery state acquired from at least one of the measurement part  20  and the detection part  31 . If the abnormality determination part  36  does not determine that the battery  10  has abnormality in step S 10 , the indicator  40  does not indicate abnormality of the battery  10 . On the other hand, if the abnormality determination part  36  determines that the battery  10  has abnormality in step S 10 , the abnormality determination part  36  acquires the used amount of the battery  10  measured by the used amount measurement part  32 . 
     In step S 20 , the abnormality determination part  36  determines whether the used amount of the battery  10  acquired when the battery  10  is thus determined to have abnormality is less than a predetermined amount. If the used amount of the battery  10  acquired when the battery  10  is thus determined to have abnormality is less than the predetermined amount, it is possible to determine that the abnormality of the battery  10  does not correspond to degradation due to the service lifetime of the battery  10  but corresponds to a fault due to a factor other than the lifetime of the battery  10 . In contrast thereto, if the used amount of the battery  10  acquired when the battery  10  is determined to have abnormality is greater than the predetermined amount, it is possible to determine that the abnormality of the battery  10  does not correspond to a fault due to a factor other than the lifetime of the battery  10  but corresponds to degradation due to the lifetime of the battery  10 . 
     Therefore, the indicator  40  indicates a first abnormality indication showing a fault of the battery  10  in step S 30  if, for example, the abnormality determination part  36  determines in step S 20  that the used amount of the battery  10  is less than the predetermined amount. On the other hand, the indicator  40  indicates a second abnormality indication showing degradation of the battery  10  in step S 50  if, for example, the abnormality determination part  36  determines in step S 20  that the used amount of the battery  10  is greater than or equal to the predetermined amount. 
     Thus, an indication of abnormality (abnormality indication) of the battery  10  is changed between a case of degradation of the battery  10  and a case of a fault of the battery  10  according to the used amount of the battery  10 . Therefore, it is possible to show the user whether the abnormality indication of the battery  10  is carried out due to degradation or is carried out due to a fault. As a result, it is possible to prevent a user from misunderstanding as if, for example, abnormality of the battery  10  corresponds to a fault due to a factor other than the lifetime although the abnormality of the battery  10  actually corresponds to degradation due to the lifetime. In the same way, it is possible to prevent a user from misunderstanding as if, for example, abnormality of the battery  10  corresponds to degradation due to the lifetime, although the abnormality of the battery  10  actually corresponds to a fault due to a factor other than the lifetime. 
       FIG. 3  is a flowchart illustrating a second example of operations of the battery abnormality indication apparatus  101 , and illustrating one example of a battery abnormality indication method carried out by the control part  30  of the battery abnormality indication apparatus  101 . The same points as those of  FIG. 2  will be omitted appropriately while the same reference numerals are given thereto. 
     If the abnormality determination part  36  determines in step S 20  that the used amount of the battery  10  is greater than or equal to the predetermined amount (NO in step S 20 ) after determining in step S 10  that the battery  10  has abnormality (YES in step S 10 ), the abnormality determination part  36  acquires the degradation degree calculated by the degradation determination part  35  in step S 40 . In step S 40 , the abnormality determination part  36  then determines whether the degradation degree of the battery  10  thus acquired when abnormality determination part  36  thus determines that the battery  10  has abnormality and the used amount of the battery  10  is greater than or equal to the predetermined amount is greater than a reference value. 
     The abnormality determination part  36 , for example, operates the alternator  11  so that the battery  10  is charged by the alternator  11  to have a charged ratio greater than or equal to a predetermined value, for determining whether the degradation degree of the battery  10  is greater than the reference value. The “charged ratio greater than or equal to the predetermined value” means, for example, a charged ratio representing the fully charged state. The “charged ratio representing the fully charged state” is, for example, 100% or a value slightly less than 100%. 
     The abnormality determination part  36  determines whether the battery  10  has been charged to have the charged ratio greater than or equal to the predetermined value, based on, for example, the charged ratio calculated by the charged ratio calculation part  33 . The abnormality determination part  36  can determine whether the charged ratio of the battery  10  becomes equal to the charged ratio representing the fully charged state based on, for example, the drooping characteristic of the charging current flowing to the battery  10  (actually, based on whether the charging current having a current value less than or equal to a predetermined current value continues flowing for a period greater than or equal to a predetermined period of time). 
     During operation of the alternator  11 , the voltage measurement part  23  cannot precisely detect the battery voltage. Therefore, the abnormality determination part  36  thus operates the alternator  11  whereby the battery  10  is charged to have the charged ratio greater than or equal to the predetermined value, and estimates the voltage value (the estimated voltage value Ve) of the battery voltage according to a predetermined arithmetic expression or map when the battery  10  has been thus charged to have the charged ratio greater than or equal to the predetermined value. For example, the abnormality determination part  36  estimates the estimated voltage value Ve according to a predetermined arithmetic expression or map based on a charged amount calculated from the accumulated value of the charging current of the battery  10  acquired from when the battery  10  is determined to have abnormality until the battery  10  has been charged to have the charged ratio greater than or equal to the predetermined value. Then, the abnormality determination part  36  determines whether the estimated voltage value Ve is less than a predetermined reference voltage value. 
     The abnormality determination part  36  can estimate that the battery voltage has not been restored to such a voltage value that the battery  10  is not determined as having abnormality (for example, a voltage value exceeding the starting performance determination threshold Vth) if the estimated voltage value Ve is less than the predetermined reference voltage value. Thus, the abnormality determination part  36  determines that the degradation degree of the battery  10  is greater than the reference value. 
     On the other hand, the abnormality determination part  36  can estimate that the battery voltage has been restored to such a voltage value that the battery  10  is not determined as having abnormality if the estimated voltage value Ve is greater than or equal to the predetermined reference voltage value. Thus, the abnormality determination part  36  determines that the degradation degree of the battery  10  is less than the reference value. 
     Thus, it is possible to determine that the degradation degree of the battery  10  has become sufficiently worse so as to show degradation of the battery  10  to a user if the degradation degree of the battery  10 , acquired when the battery  10  is determined to have abnormality and the used amount of the battery  10  is determined to be greater than or equal to the predetermined amount, is greater than the reference value. In contrast thereto, it is possible to determine that the degradation degree of the battery  10  has not become sufficiently worse so as to show degradation of the battery  10  to a user if the degradation degree of the battery  10  acquired when the battery  10  is determined to have abnormality is less than the reference value. 
     Therefore, the indicator  40  indicates the second abnormality indication showing degradation of the battery  10  in step S 50  if, for example, the abnormality determination part  36  determines that the used amount of the battery  10  is greater than or equal to the predetermined amount (NO in step S 20 ) and the degradation degree of the battery  10  is greater than the reference value (YES in step S 40 ). On the other hand, the indicator  40  does not carry out abnormality indication of the battery  10  if, for example, the abnormality determination part  36  determines that the degradation degree of the battery  10  is less than or equal to the reference value (NO in step S 40 ). Thus, it is possible to clearly show a user that the degree degradation of the battery  10  has become worse to some degree, and prevent an abnormality indication showing degradation of the battery  10  from being carried out even if the degradation degree of the battery  10  has not become sufficiently worse, for example. 
       FIG. 4  is a flowchart illustrating a third example of operations of the battery abnormality indication apparatus  101 , and illustrating one example of a battery abnormality indication method carried out by the control part  30  of the battery abnormality indication apparatus  101 . The same points as those of  FIGS. 2 and 3  will be omitted appropriately while the same reference numerals are given thereto. 
     In steps S 11  and S 12 , the abnormality determination part  36  determines whether the battery  10  has abnormality, based on the battery state acquired from at least one of the measurement part  20  and the detection part  31 . 
     In step S 11 , if it is detected that the ignition switch  14  is switched from its turned off state into its turned on state and the engine  12  is started with power from the battery  10 , the abnormality determination part  36  acquires vehicle data including the battery state from at least one of the measurement part  20  and the detection part  31 . 
     In step S 12 , the abnormality determination part  36  determines whether performance (starting performance of the battery  10 ) of the battery  10  for starting the engine  12  is degraded. Thereby, the abnormality determination part  36  can determine whether a starting failure of the engine  12  is beginning to occur due to degradation of the starting performance of the battery  10 , and thus, can determine whether the battery  10  has abnormality. The abnormality determination part  36  determines that a fault concerning starting the engine  12  is beginning to occur if the abnormality determination part  36  determines that, for example, the starting performance of the battery  10  is degraded, and then, determines that the battery  10  has abnormality. 
     The abnormality determination part  36  determine that the starting performance of the battery  10  is degraded if, for example, the voltage measurement part  23  has measured that the minimum value of the battery voltage acquired when the engine  12  is being started is less than or equal to the predetermined starting performance determination threshold Vth, and then, determines that the battery  10  has abnormality. The starting performance determination threshold Vth is a threshold for determining whether the starting performance of the battery  10  is degraded, and is one example of an abnormality determination condition for determining whether the battery  10  has abnormality. 
     It is possible that the abnormality determination part  36  determines that the starting performance of the battery  10  is degraded and determines that the battery  10  has abnormality, if, for example, idling stop of the engine  12  is inhibited by the engine control part  13  due to the fact that the starting performance of the battery  10  is degraded. Thus, even if idling stop of the engine  12  is automatically inhibited according to the corresponding determination of the engine control part  13 , a user can recognize the reason therefor, i.e., which one of a fault of the battery  10  and degradation of the battery  10  causes the inhibition, by checking an abnormality indication of the battery  10  carried out in step S 30  or step S 50  described later. 
     Note that the actual method of determining whether the starting performance of the battery  10  is degraded by the abnormality determination part  36  can be any method. For example, it is possible that the abnormality determination part  36  determines whether the starting performance of the battery  10  is degraded based on at least one of the battery temperature measured by the temperature measurement part  22 , the internal resistance measured by the internal resistance calculation part  34 , and the charged ratio calculated by the charged ratio calculation part  33 . 
     The indicator  40  does not carry out an abnormality indication of the battery  10  if the abnormality determination part  36  does not determine that the starting performance of the battery  10  is degraded, in step S 12 . On the other hand, the abnormality determination part  36  determines, in steps S 13 , S 21 , and S 22 , whether the abnormality of the battery  10  corresponds to a fault, if the abnormality determination part  36  determines in step S 12  that the starting performance of the battery  10  is degraded. 
     In step S 13 , the abnormality determination part  36  determines whether the variation of the internal resistance Ri calculated by the internal resistance calculation part  34  exceeds a predetermined threshold Rth. 
       FIG. 5  illustrates one example of a temporal change in the internal resistance Ri of the battery  10 . “Time” on the abscissa in  FIG. 5  can be replaced with “the used amount of the battery  10 ”. 
     Whether the abnormality of the battery  10  corresponds to a fault can be determined based on the variation of the internal resistance Ri. If the starting performance of the battery  10  degrades due to degradation of the battery  10 , the internal resistance Ri does not sharply change. In contrast thereto, if the starting performance of the battery  10  degrades due to a fault of the battery  10  (for example, damage of an electrode column of the battery  10 ), the internal resistance Ri changes sharply. Note that, if the used amount of the battery  10  (for example, the accumulated value of the charged and discharged amount of the battery  10 , the number of start times of the engine  12  started by the power of the battery  10 , or so) is relatively great, degradation of the battery  10  becomes worse sharply. Therefore, the internal resistance Ri may change greatly even though the battery  10  has no fault. 
     Therefore, the abnormality determination part  36  determines that the abnormality of the battery  10  corresponds to a fault if the abnormality determination part  36  determines that the variation of the internal resistance Ri is greater than the predetermined threshold Rth and the used amount of the battery  10  is less than or equal to a predetermined amount. Thus, the abnormality determination part  36  determines that the abnormality of the battery  10  corresponds to a fault if the variation of the internal resistance Ri is relatively great even through the battery  10  has not been used so much. The abnormality determination part  36  determines that the abnormality of the battery  10  does not corresponds to a fault if the abnormality determination part  36  determines that the used amount of the battery  10  is greater than or equal to the predetermined amount even if the abnormality determination part  36  determines that the variation in the internal resistance Ri is greater than the predetermined threshold Rth. 
     In step S 13  of  FIG. 4 , a difference ΔRi is shown which is acquired by subtracting the previous value of the internal resistance Ri from the current value of the internal resistance Ri, as one example of the variation of the internal resistance Ri. In step S 13 , the abnormality determination part  36  compares the current value of the internal resistance Ri with the previous value of the internal resistance Ri, for example, and determines whether the difference ΔRi exceeds the predetermined threshold Rth. 
     The “current value of the internal resistance Ri” is the internal resistance currently calculated by the internal resistance calculation part  34 , and can be a value statistically calculated using the currently calculated internal resistance and the previously calculated internal resistance (for example, the average thereof). In the same way, the “previous value of the internal resistance Ri” is the internal resistance previously calculated by the internal resistance calculation part  34 , and can be a value statistically calculated using the previously calculated internal resistance and the further previously calculated internal resistance (for example, the average thereof). 
     By normalizing the current value of the internal resistance Ri and the previous value of the internal resistance Ri, respectively, using at least one of the specific charged ratio and battery temperature, the accuracy in determining whether the battery  10  has a fault improves. 
     The “current value of the internal resistance Ri” and the “previous value of the internal resistance Ri” mean, respectively, for example, the internal resistance Ri in the current trip and the internal resistance Ri in the previous trip. The “trip” means a period of time from when the ignition switch  14  is switched from the turned off state into the turned on state until the ignition switch  14  is switched from the turned on state into the turned off state. It is also possible that the “current value of the internal resistance Ri” and the “previous value of the internal resistance Ri” mean, respectively, for example, the internal resistance Ri acquired when the engine  12  was started most recently and the internal resistance Ri acquired when the engine  12  was started previously to most recently. 
     The abnormality determination part  36  determines that the battery  10  is determined to have abnormality due to insufficient charging of the battery  10  if the abnormality determination part  36  determines in step S 13  that the difference ΔR acquired when the battery  10  is determined to have abnormality is less than or equal to the predetermined threshold Rth. Then, the abnormality determination part  36  determines that the abnormality of the battery  10  does not correspond to a fault. The abnormality determination part  36  determines the degradation degree of the battery  10  in steps S 41 -S 44  if the abnormality determination part  36  determines in step S 13  that the difference ΔR acquired when the battery  10  is determined to have abnormality is less than or equal to the predetermined threshold Rth. 
     On the other hand, the abnormality determination part  36  determines in steps S 21  and S 22  whether the used amount of the battery  10  is less than or equal to a predetermined amount, as will be described below, if the abnormality determination part  36  determines that the difference ΔR acquired when the battery  10  is determined to have abnormality is greater than the predetermined threshold Rth. The order between step S 21  and step S 22  can be changed. 
     In step S 21 , the abnormality determination part  36  determines whether the accumulated value of the charged and discharged amount of the battery  10  is less than a predetermined current amount Ith. In step S 22 , the abnormality determination part  36  determines whether the number of start times of the engine  12  is less than a predetermined number of times Eth. The abnormality determination part  36  determines that the used amount of the battery  10  is less than or equal to the predetermined amount if the accumulated value of the charged and discharged amount of the battery  10  is determined as being less than the predetermined current amount Ith and the number of start times of the engine  12  is determined as being less than the predetermined number of times Eth. 
     The indicator  40  indicates the first abnormality indication showing a fault of the battery  10  in step S 30  if the abnormality determination part  36  determines that the variation of the internal resistance Ri of the battery  10  is greater than the predetermined threshold Rth, and also, the used amount of the battery  10  is less than or equal to the predetermined amount (YES in S 13 , YES in S 21 , and YES in S 22 ). 
     On the other hand, the abnormality determination part  36  determines that the used amount of the battery  10  is greater than or equal to the predetermined amount if the accumulated value of the charged and discharged amount of the battery  10  is determined as being greater than or equal to the predetermined current amount Ith (NO in S 21 ) or the number of start times of the engine  12  is determined as being greater than or equal to the predetermined number of times Eth (NO in S 22 ). The abnormality determination part  36  determines that the abnormality of the battery  10  does not correspond to a fault if the used amount of the battery  10  is determined as being greater than or equal to the predetermined amount (NO in S 21  or NO in S 22 ) even if the difference AR is greater than the predetermined threshold Rth (YES in S 13 ), and determines in steps S 41  to S 44  the degradation degree of the battery  10 . 
     In steps S 41 -S 44 , the abnormality determination part  36  determines whether the battery  10  is degraded so much that it is not possible to recover from the degradation of starting performance of the battery  10 . 
     In steps S 41  and S 42 , the abnormality determination part  36  operates the alternator  11  in such a manner that charging control is carried out where discharging of the battery  10  is inhibited and the battery  10  is charged to have the charged ratio greater than or equal to the predetermined value. When the charging control is carried out, the abnormality determination part  36  inhibits idling stop of the engine  12 , for example, and the charging voltage applied to the battery  10  is increased by the alternator  11 . 
     When the battery  10  has been charged to have the charged ratio greater than or equal to the predetermined value and the charging control is finished, the abnormality determination part  36  derives, in step S 43 , the voltage value (the estimated voltage value Ve) of the battery voltage acquired when the battery  10  is charged to have the charged ratio greater than or equal to the predetermined value, using a predetermined arithmetic expression(s) or a map. 
       FIG. 6  illustrates one example of relationships between the charged amount and the estimated voltage value Ve. “Vo” denotes the battery voltage acquired when the starting performance of the battery  10  is determined as being degraded in step S 12  of  FIG. 4 . “Vo” is expressed as a minimum value of the battery voltage acquired when the engine  12  is started. “Vth” denotes the starting performance determination threshold for determining whether the starting performance of the battery  10  is degraded. The abscissa denotes the charged amount X calculated from the accumulated value of the charging current of the battery  10  from when the starting performance of the battery  10  is determined as being degraded in step S 12  of  FIG. 4  until the battery  10  has been charged to have the charged ratio greater than or equal to the predetermined value. 
     The abnormality determination part  36  calculates the estimated voltage value Ve according to a linear arithmetic expression “Ve=A×B+Vo”, for example. The linear arithmetic expression “Ve=A×B+Vo” is equivalent to the linear expression Y shown in  FIG. 6 . 
     In the linear arithmetic expression “Ve=A×B+Vo”, “B” denotes “(charged amount X)/(fully charged capacity of battery  10 )”. “A” denotes a constant value (for example, “1”). The reason why “A” can be defined as “1” is that, as shown in  FIG. 7 , the relationship shown in  FIG. 6  can be approximated to such a relationship that, as the charged ratio increases 1%, the battery voltage increases 0.01 V. 
     In step S 44  of  FIG. 4 , the abnormality determination part  36  determines whether the thus acquired estimated voltage value Ve is less than the starting performance determination threshold Vth. If the abnormality determination part  36  determines that the estimated voltage value Ve is less than the starting performance determination threshold Vth (if the equation X=Xa holds in  FIG. 6 ), the abnormality determination part  36  determines that the abnormality of the battery  10  is such that the battery  10  is degraded so much that it is not possible to restore the starting performance of the battery  10 . On the other hand, if the abnormality determination part  36  determines that the estimated voltage value Ve is greater than or equal to the starting performance determination threshold Vth (if the equation X=Xb holds in  FIG. 6 ), the abnormality determination part  36  determines that the starting performance of the battery  10  has been restored through the charging control in step S 41 . 
     If the abnormality determination part  36  determines in step S 44  that the estimated voltage value Ve is less than the starting performance determination threshold Vth, the indicator  40  indicates the second abnormality indication showing degradation of the battery  10  in step S 50 . On the other hand, if the abnormality determination part  36  determines in step S 44  that the estimated voltage value Ve is greater than or equal to the starting performance determination threshold Vth, the indicator  40  does not carry out the second abnormality indication showing degradation of the battery  10 . 
     Thus, the battery abnormality indication apparatus  101  has been described by the embodiments. However, the present disclosure is not limited to such embodiments. It is possible to make various modifications and/or improvements by combining with another embodiment(s) partially or with the entirety thereof, partially replacing with another embodiment(s), or so, within the scope of the claims. 
     For example, what is used to be based on when determining whether the battery  10  has abnormality is not limited to the variation in the internal resistance, and it is also possible to determine whether the battery  10  has abnormality based on the battery voltage or the battery current. It is also possible that whether the battery  10  has abnormality is determined by combining the variation in the internal resistance with another parameter(s) such as the battery voltage, the battery current, the battery temperature, the charged ratio, and/or the like. 
     The battery voltage when the engine  12  is started has a correlation also with the internal resistance. The greater the internal resistance is, the less the battery voltage when the engine  12  is started is. Therefore, it is possible that the estimated voltage value Ve is determined based on the internal resistance Ri, or based on both the internal resistance Ri and the charged amount X. Also, it is possible that the estimated voltage value Ve is corrected using a correction map or so according to the battery temperature. 
     According to the embodiments, if it is determined that a battery has abnormality in a situation where the used amount of the battery is relatively small, it is possible to consider that the abnormality of the battery does not correspond to degradation due to an increase in the used amount of the battery but corresponds to a fault. In contrast thereto, if it is determined that the battery has abnormality in a situation where the used amount of the battery is relatively great, it is possible to consider that the abnormality of the battery does not correspond to a fault but corresponds to degradation due to an increase in the used amount of the battery. 
     Therefore, according to the embodiments, an abnormality indication of the battery is changed between a case of degradation of the battery and a case of a fault of the battery  10  according to the used amount of the battery. Therefore, it is possible to show a user whether the abnormality indication of the battery is due to degradation or a fault.