JP2005259624A - Battery status detecting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery status detecting apparatus uniquely defining a deteriorated state of a battery even when the battery is deteriorated in various modes. <P>SOLUTION: The battery status detecting apparatus measures open circuit voltage of a battery in a state of full charge (S204), calculates reduced amount ΔSOH1 of SOH (State Of Health) of a lead battery on the side of a high OCV (open circuit voltage)(S210). When peak voltage Vp of the lead battery is 8V and less when an engine is started (S310), a reduced amount ΔSOH2 of SOH in the lead battery on a low OCV side by SOH map between a discharge voltage and the open circuit voltage is calculated (S312), and the deteriorated state SOH of the lead battery is calculated from ΔSOH1 and ΔSOH2 (S212, S314). SOH, etc., close to a real value of the lead battery cell are calculated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a battery state detection device, and more particularly to a battery state detection device that detects a state of a battery.

  In recent years, the role of battery state monitoring and battery state control has become more and more important as the load on the batteries used in automobiles, portable devices, and the like has increased with the increase in performance. For example, in the case of a battery for an automobile, a technique for keeping the battery in a battery state suitable for these uses is desired in order to cope with idle stop start (ISS) or regenerative charging performed to reduce exhaust gas. Lead batteries are one of the typical batteries that can be applied to these applications.

  Conventionally, internal resistance, discharge voltage, open circuit voltage, and the like have been used as materials for determining a battery state such as a deteriorated state and a charged state, and are used as indicators of a battery state suitable for these applications. For example, various techniques for calculating a battery state by comparing with a data map obtained by measuring a voltage at the time of engine start and a direct current internal resistance in advance have been proposed (see, for example, Patent Document 1). In the deterioration determination, a technique for determining the degree of deterioration by the amount of change in the open circuit voltage per unit electric quantity discharge to determine the life, or a technique for determining the degree of deterioration from the open circuit voltage in a fully charged state and using it for the ISS determination Is disclosed (for example, see Patent Document 2).

  As an index indicating the degree of deterioration of a deteriorated battery (deterioration state), the above-described change amount of the open circuit voltage per unit electric quantity discharge and the open circuit voltage in a fully charged state are often used. Also, recently, a parameter called SOH (State Of Health) defined by (full charge capacity / initial full charge capacity) × 100% has been established as an index representing the deterioration state.

JP-A-7-63830 JP 2003-028940 A

  However, when actually investigating deteriorated batteries in various deterioration modes, there are many batteries with greatly different discharge characteristics even if these amounts are the same, and it is difficult to uniquely define the degree of deterioration of the deteriorated battery. For example, taking the detection of the degree of deterioration of an open circuit voltage (OCV) of a lead battery as an example, in a battery that has deteriorated due to lead sulfate, the area in which the large lead sulfate is not charged in a discharged state is used. In a battery that cannot be used and deteriorated due to muddy formation, the active material that has fallen off is not discharged in a charged state, and the region where the OCV is small cannot be used.

  An object of the present invention is to provide a battery state detection device capable of uniquely defining a deterioration state of a battery even when the battery has deteriorated in various modes.

  In order to solve the above-described problems, the present invention provides a battery state detection device that detects a state of a battery, a first SOH decrease amount calculating unit that calculates a decrease amount of SOH of the battery in a fully charged state, Calculated by a second SOH decrease amount calculating means for calculating the amount of SOH decrease of the battery when the voltage of the battery due to rate discharge is not more than a predetermined value, and the first and second SOH decrease amount calculating means. SOH calculating means for calculating the SOH value of the battery from both of the amount of SOH reduction.

  In the present invention, the first SOH decrease amount calculation means calculates the SOH decrease amount of the battery in the fully charged state, and the second SOH decrease amount calculation means causes the battery voltage due to high rate discharge to be less than or equal to a predetermined value. The SOH decrease amount of the battery at this time is calculated, and the SOH calculation unit calculates the SOH value of the battery from both the SOH decrease amounts calculated by the first and second SOH decrease amount calculation units. According to the present invention, the battery SOH reduction amount in the fully charged state and the battery SOH reduction amount due to the high rate discharge are calculated by separate first and second SOH reduction amount calculation units, respectively. The SOH reduction amount of the battery can be accurately calculated according to the deterioration mode of the battery, and the SOH of the battery is calculated from both the SOH reduction amount calculated by the first and second SOH reduction amount calculation means by the SOH calculation means. Therefore, it is possible to calculate a value of SOH that is uniquely close to the true value of the SOH of the battery.

  In the present invention, the first and second SOH decrease amount calculating means may calculate the decrease amount of SOH from the open circuit voltage, internal resistance or discharge voltage of the battery. At this time, the first SOH decrease amount calculating means calculates the SOH decrease amount from the open circuit voltage when the battery is fully charged, and the second SOH decrease amount calculating means is an increase value of the internal resistance of the battery. From the above, the amount of decrease in SOH may be calculated. Moreover, you may make it further provide the life calculation means which calculates the life expectancy of a battery from the value of several SOH in the different time calculated by the SOH calculation means. In this case, it is preferable that the life expectancy calculating means calculates the life expectancy of the battery from the progress speed of the deterioration state of the battery. Further, an SOC calculation means for calculating the SOC value of the battery in a non-full charge state, an SOC value calculated by the SOC calculation means, and a decrease amount of the SOH of the battery calculated by the second SOH reduction amount calculation means And a state of charge calculation means for calculating the state of charge of the battery based on the SOH calculated by the SOH calculation means. At this time, the SOC calculation means may calculate the SOC value of the battery in the non-full charge state from the open circuit voltage, internal resistance or discharge voltage of the battery.

  According to the present invention, the battery SOH reduction amount in the fully charged state and the battery SOH reduction amount due to the high rate discharge are calculated by separate first and second SOH reduction amount calculation units, respectively. The SOH reduction amount of the battery can be accurately calculated according to the deterioration mode of the battery, and the SOH of the battery is calculated from both the SOH reduction amount calculated by the first and second SOH reduction amount calculation means by the SOH calculation means. Since the value of SOH is calculated, it is possible to obtain an effect that the value of SOH that is uniquely close to the true value of SOH of the battery can be calculated.

  Hereinafter, an embodiment in which the present invention is applied to a battery state detection device that detects a battery state of a vehicle lead battery 75D26 will be described with reference to the drawings.

(Constitution)
As shown in FIG. 2, the battery state detection device 11 of the present embodiment is fixed to the side surface of the lead battery 1 on the side away from the vent plug of the lead battery 1 (75D26), and the deterioration state of the lead battery 1 ( A microcomputer (hereinafter abbreviated as “microcomputer”) 8 for calculating battery states such as SOH), state of charge (SOC), and life expectancy. A sensor insertion hole is formed in the partition wall in the central part of the battery case of the lead battery 1, and a temperature sensor 7 such as a thermistor is inserted into the sensor insertion hole and fixed with an adhesive.

  The microcomputer 8 includes a CPU that functions as a central processing unit, a ROM that stores data such as a basic control program of the battery state detection device 11 and a map that will be described later, a RAM that functions as a work area of the CPU, an A / D converter, and a host An interface for communicating with the vehicle-side microcomputer 10 is included.

  A positive terminal of the lead battery 1 is connected to a central terminal of an ignition switch (hereinafter referred to as IGN switch) 9 through a current sensor 6. The IGN switch 9 has an OFF terminal, an ON / ACC terminal, and a START terminal in addition to the center terminal, and can be switched and connected in a rotary manner.

  The output terminal of the current sensor 6 is connected to an A / D converter built in the microcomputer 8, and the Hall voltage output from the current sensor 6 is converted into a digital value by the A / D converter. Can be captured as a digital value. Further, the bipolar terminals of the lead battery 1 are connected to another A / D converter built in the microcomputer 8, and the microcomputer 8 can take in the voltage across the lead battery 1 as a digital value. Furthermore, the output terminal of the temperature sensor 7 is connected to another A / D converter, and the microcomputer 8 can capture the temperature of the lead battery 1 as a digital value. Note that the battery state detection device 11 includes such wiring.

  On the other hand, a starter 3 for starting the engine 4 by transmitting the rotational driving force to the rotating shaft of the engine 4 via a clutch mechanism (not shown) is disposed on the vehicle side. Further, the rotation shaft of the engine 4 can transmit power to the generator 2 via a clutch mechanism (not shown). When the engine 4 is in a rotating state, the generator 2 is operated via this clutch mechanism. Then, the electric power from the generator 2 is supplied (charged) to the auxiliary machine 5 such as an air conditioner and a radio or the lead battery 1. Such engine control and the like are executed by the vehicle-side microcomputer 10.

  The ON / ACC terminal of the IGN switch 9 is connected to one end of the generator 2 through the auxiliary machine 5 and a rectifying element that allows current flow in one direction. The START terminal is connected to one end of the starter 3. Furthermore, the other end of the generator 2, the starter 3 and the auxiliary machine 5, the negative terminal of the lead battery 1, and the microcomputer 8 are connected to the ground, respectively.

(Operation)
Next, with reference to a flowchart, the operation of the battery state detection device 11 of the present embodiment will be described with a CPU of the microcomputer 8 (hereinafter simply referred to as a CPU) as a subject. The CPU executes a battery state calculation routine for calculating a battery state such as the SOC of the lead battery 1 when the microcomputer 8 is powered on.

  As shown in FIG. 3, in the battery state calculation routine, first, in step 100, it is determined whether or not the current flowing through the current sensor 6 is a predetermined value (for example, 0.05 A) or more. It is determined whether the terminal is connected to the ON / ACC terminal or the START terminal.

  If the determination in step 100 is negative, that is, if the center terminal of the IGN switch 9 is connected to the OFF terminal (ignition is off), the ignition is off in step 202. It is determined whether 6 hours have passed since then. Note that the determination as to whether or not the ignition has been turned off can be made by assuming that the ignition has been turned off when the current flowing through the current sensor 6 becomes less than a predetermined value, as described above. This can be determined by starting the time count by the CPU internal clock.

  If the determination in step 202 is negative, the process returns to step 100. If the determination is affirmative, in the next step 204, the open circuit voltage (OCV) of the lead battery 1 is captured. Accordingly, the OCV of the lead battery 1 is measured every 6 hours after the ignition is turned off. In the next step 206, it is determined whether or not the lead battery 1 is fully charged based on the measured OCV. Such a determination is made, for example, by using a 75D26 relation map (SOC (OCV) map) between the state of charge (SOC) of the lead battery 1 in a new state and the OCV shown in Table 1 below. It can be performed appropriately by correcting and using it according to the deterioration state (SOH).

  When the determination in step 206 is affirmative, the lead battery 1 is in a fully charged state (SOC = 100%), and in the next step 210, ΔSOH1 = 100% − using the SOH (OCV) map in Table 2 below. The SOH reduction amount ΔSOH1 of the lead battery 1 in the fully charged state is calculated by SOH (OCV) and stored in the RAM.

  In the next step 212, an SOH reduction amount ΔSOH2 (see step 312) of the lead battery 1 to be described later is read from the RAM, and SOH = 100% − (ΔSOH1 + ΔSOH2) (hereinafter, this equation is referred to as equation 1). The SOH of the lead battery 1 in the charged state is calculated. In the initial setting process (not shown) of the battery state calculation routine, the initial value of SOH decrease amount ΔSOH2 = 0 is developed from the ROM to the RAM, and in step 212, the SOH decrease amount ΔSOH2 in step 312 described later. Until S is calculated, the SOH decrease amount ΔSOH2 is set to 0, that is, SOH of the lead battery 1 is calculated by SOH = 100% −ΔSOH1. Next, in step 214, the SOH calculated in step 212 and the current time are stored in the RAM, and the process proceeds to step 102.

  When a negative determination is made in step 206, in step 216, the state of charge SOC1 based on the open circuit voltage of the lead battery 1 is calculated from the OCV of the lead battery 1 measured in step 204 using the SOC (OCV) map described above. In the next step 218, the SOC of the lead battery 1 is calculated by SOC = 100% × {100% − (SOC1 + SOH2)} / SOH (hereinafter, this equation is referred to as equation 2) and stored in the RAM. Proceed to In step 218, similarly to step 212, the SOH decrease amount ΔSOH2 is calculated as 0 until the SOH decrease amount ΔSOH2 is calculated in step 312 described later.

  On the other hand, when the determination in step 100 is affirmative, that is, when the center terminal of the IGN switch 9 is connected to the ON / ACC terminal or the START terminal (ignition is in an on state), lead is detected in step 302. The discharge voltage E of the battery 1 is measured and stored in the RAM, and in the next step 304, it is determined whether or not the lead battery 1 is fully charged. In this step 304, for example, when the discharge voltage E for the past 30 minutes falls within a range of 200 mV of 13.8 V or more at a rate of 90% or more, it is determined that the battery is fully charged, and otherwise, it is determined that it is not fully charged. That's fine.

  If the determination in step 304 is affirmative, the process returns to step 100. If the determination is negative, in step 306, the Hall voltage output from the current sensor 6 is monitored to connect the IGN switch 9 to the START terminal. It is determined whether or not.

  FIG. 6 schematically shows the current flowing through the lead battery 1 (current sensor 6) when the engine is started. The current waveform of the lead battery 1 at the start of the engine is such that after the start of energization of the engine start current when the IGN switch 9 is located at the START position (time ts), a rapid first-stage pulse discharge to the starter 3 is performed. The current waveform falls sharply and a peak appears after about 50 ms (time tp). After that, the engine start is completed after a few attenuations. Although the current waveform is affected by the structure of the engine 4, the friction of the clutch connecting the engine 4 and the starter 3, etc., the waveform is generally as shown in FIG. Therefore, in step 306, it can be determined whether or not the IGN switch 9 is connected to the START terminal by determining whether or not a large current of a predetermined value or more has flowed.

  When a negative determination is made at step 306, the process returns to step 100. When an affirmative determination is made, the temperature T and peak voltage Vp of the lead battery 1 (discharge voltage of the lead battery 1 at time tp in FIG. 6) are measured at step 308. To do.

  Next, in step 310, it is determined whether or not the peak voltage Vp is 8 V or less. If the determination is negative, the process returns to step 100. If the determination is affirmative, in the next step 312, SOH2 ( (Temperature T, Peak Voltage Vp, OCV) Map, and the SOH reduction amount ΔSOH2 of the lead battery 1 in the region where the OCV is low is calculated by ΔSOH2 = 100% −SOH2 (temperature T, peak voltage Vp, OCV). .

  Although the discharge voltage depends on the current, the current at the time of engine start corresponds to the type of the lead battery, so the engine start current of the vehicle on which the lead battery of that type is mounted is examined in advance, and the SOH ( Temperature T, peak voltage Vp, OCV) map is used. FIG. 1 illustrates an SOH (peak voltage Vp, OCV) map at 25 ° C. with 75D26. However, in the lead battery 1, Vp> 8V data is low in correlation with SOH, and therefore Vp ≦ 8V. Data must be selected and applied to the SOH (peak voltage Vp, OCV) map. In general, since the battery state depends on the temperature, a plurality of SOH (peak voltage Vp, OCV) maps are developed from the ROM to the RAM at every predetermined temperature (for example, every 10 ° C.), and measured in step 308. It is preferable to calculate the OCV of the lead battery 1 at the peak voltage Vp by proportionally calculating (correcting) two SOH (OCV) maps close to the temperature T.

  In the next step 314, the SOH of the lead battery 1 is calculated. The total SOH reduction amount ΔSOH of the lead battery 1 is (ΔSOH1 + ΔSOH2), and the SOH can be calculated by the above-described equation 1. Next, in step 316, the SOH calculated in step 316 and the current time are stored in the RAM, and in step 318, the SOC of the lead battery 1 is calculated and stored in the RAM according to Equation 2, and the process proceeds to step 102.

  In step 102, in order to eliminate the calculation result of the initial value in the initial setting process, the SOH decrease amount ΔSOH1 of the lead battery 1 in the fully charged state and the SOH decrease of the lead battery 1 at a low OCV during high rate discharge. Both the amount ΔSOH2 are calculated, and it is determined whether or not the previous time and the previous SOH were calculated this time. If the determination is negative, the process returns to step 100. If the determination is affirmative, the remaining life of the lead battery 1 is calculated in the next step 106.

  If the lead battery 1 is only deteriorated due to mudification, as shown in FIG. 1, the change due to deterioration is small in a region where the OCV is large, such as a fully charged state, and the OCV does not change greatly. The life expectancy of the lead battery 1 can be calculated from the change over time. In the present embodiment, in step 106, life expectancy = previous SOH × {previous SOH calculation time−previous SOH calculation time) / (previous SOH−previous SOH) − (current SOH calculation time−previous SOH calculation time) The relationship between the SOH calculation results of the past two or more times and the time is extrapolated to SOH = 0, and the time from the present to SOH = 0 is defined as the remaining life of the lead battery 1. In other words, in this embodiment, the surname of the lead battery 1 is calculated (calculated) from the progress speed of the deterioration state of the lead battery 1.

  In the next step 108, the latest SOC and SOH of the lead battery 1 and the remaining life calculated in step 106 are output to the vehicle-side microcomputer 10 via the interface, and the process returns to step 100. The vehicle-side microcomputer 10 transmits the SOC or the like notified from the microcomputer 8 to a panel control unit (not shown) that controls the vehicle installation panel, and the battery status of the lead battery 1 is displayed on the installation panel by characters or graphs. The Therefore, the driver can grasp the battery state of the lead battery 1 by looking at the installation panel.

(Action etc.)
Next, operations, effects, and the like of the battery state detection device 11 of the present embodiment will be described.

  As described above, in general, lead batteries are not charged in a deteriorated mode due to lead sulfate, and coarse lead sulfate is not charged in a discharged state and the OCV is large, and the active material is dropped in the deteriorated mode due to muddy formation. Thus, the active material that has fallen off is not discharged in the charged state, and the region where the OCV is small cannot be used. In the battery state detection device 11 of the present embodiment, the OCV region of the lead battery 1 that cannot be used in this way is divided into a high OCV side and a low OCV side, an SOH decrease amount ΔSOH1 on the high OCV side, and an SOH on the low OCV side. The reduction amount ΔSOH2 is calculated using an effective calculation method (which can be calculated with high accuracy), and the SOH of the lead battery 1 is calculated using both ΔSOH1 and ΔSOH2 as shown in Equation 1. Therefore, SOH close to the true value of SOH of the lead battery 1 can be calculated.

  That is, on the high OCV side, the stable OCV of the lead battery 1 is measured in the high OCV region due to the fully charged state before a large amount of electricity is input / output (step 204), and the SOH decrease amount ΔSOH1 is calculated. (Step 210). On the low OCV side, in the low OCV region due to high rate discharge, as shown in step 310, when the peak voltage Vp at the time of engine start is 8V or less (the battery voltage due to high rate discharge is below a predetermined value). In some cases, the SOH decrease amount ΔSOH2 is calculated by applying to the SOH (temperature T, peak voltage Vp, OCV) map shown in FIG. 1 (step 312). Since the SOH of the lead battery 1 is calculated by using both ΔSOH1 and ΔSOH2 according to Equation 1 (steps 212 and 314), it is uniquely (highly accurate regardless of the high OCV side and the low OCV side). The SOH of the lead battery 1 can be calculated.

  Moreover, in the battery state detection apparatus 11 of this embodiment, as shown in Formula 3, the life expectancy of the lead battery 1 is calculated from the progress speed of the deterioration state of the lead battery 1 by a plurality of SOH at different times ( Step 106) Since the accuracy of the SOH of the lead battery 1 is high as described above, the life expectancy close to the true value of the lead battery 1 can be calculated. Furthermore, in the battery state detection device 11 of the present embodiment, the SOC 1 of the lead battery 1 in the non-full charge state is calculated (step 216), and the SOC of the lead battery 1 is calculated by the equation 2 (steps 218 and 318). ), The SOC of the lead battery 1 with high accuracy in consideration of the deterioration state can be calculated.

  In the present embodiment, the SOH reduction amount ΔSOH1 of the lead battery 1 is illustrated in step 210 at full charge (SOC = 100%). However, the present invention is not limited to this, and a large amount of electricity is generated on the high OCV side. You may make it calculate SOH reduction | decrease amount (DELTA) SOH1 by measuring stable OCV of the lead battery 1 before entering / exiting. Therefore, the “full charge state” of the present invention means full charge and the vicinity of full charge.

  In the present embodiment, an example is shown in which the peak voltage Vp at the time of engine start is measured in consideration of the lead battery 1 being a vehicle battery (step 308), but the present invention is not limited to this. When the auxiliary machine 5 such as an air conditioner is used, the voltage of the lead battery 1 may be measured to calculate the SOH reduction amount ΔSOH2 of the lead battery 1.

  Furthermore, in the present embodiment, 75D26 is exemplified for the lead battery 1 and ΔSOH2 is calculated when the peak voltage Vp is 8 V or less. However, the present invention is not limited to the type of the lead battery or the exemplified peak voltage Vp. Needless to say, the present invention is not limited and can be appropriately changed according to the characteristics of the battery applied by those skilled in the art.

  In the present embodiment, an example is shown in which the open circuit voltage (OCV) and the peak voltage Vp (discharge voltage) are measured, and ΔSOH1 and ΔSOH2 are calculated by a decrease in OCV. However, the present invention is limited to this. Instead of this, ΔSOH1 and ΔSOH2 may be calculated from an increase (increase value) in the internal resistance of the lead battery 1. For example, in order to calculate ΔSOH2 from the increase in internal resistance of the lead battery 1, since the battery state detection device 11 includes the current sensor 6, in step 308, in addition to the peak voltage Vp, the peak current Ip (in FIG. In step 312, (increase in internal resistance) = (discharge voltage before engine start-peak voltage Vp) / (current before engine start-peak current Ip). ) And apply to the internal resistance map.

  Furthermore, in this embodiment, although the example which performs calculation, such as (DELTA) SOH1, (DELTA) SOH2, SOH, SOC, and life expectancy by the microcomputer 8, was shown, you may make it perform these calculations by the vehicle side microcomputer 10. FIG. In this case, the microcomputer 8 measures the OCV of the lead battery 1 (step 204), the voltage E (step 304), the lead battery T, the peak voltage Vp (step 308), etc. The microcomputer on the vehicle side generally uses a microcomputer with higher processing capability than the microcomputer 8, so the load on the microcomputer 8 is reduced and the calculation time is shortened as a whole. There is an advantage that you can.

  Next, examples of the battery state detection device manufactured according to the above embodiment will be described. In addition, it describes together about the battery state detection apparatus produced for the comparison. The battery state detection devices of the example and the comparative example differ from the above-described embodiment in which the microcomputer 8 is connected to the vehicle-side microcomputer 10 in that the microcomputer 8 is connected to a notebook computer. Therefore, the SOC, SOH, and life expectancy are output to the notebook computer (see step 108 in FIG. 3), and the output data is displayed on the display of the notebook computer and stored in the memory of the notebook computer.

(Example 1)
In the battery state detection apparatus of Example 1, the CPU was caused to execute the battery state calculation routine shown in FIG.

(Comparative Example 1)
In the battery state detection device of Comparative Example 1, the CPU was caused to execute the battery state calculation routine shown in FIG. This battery state calculation routine is different from the battery state calculation routine of the first embodiment in that the 300th step (steps 302 to 318) in FIG. 3 is omitted. In other words, the battery state detection device of Comparative Example 1 uses only the SOH decrease amount ΔSOH1 on the high OCV side when calculating the SOH of the lead battery (calculates the SOH of the lead battery from the fully charged OCV). The SOH reduction amount ΔSOH2 on the low OCV side is not used.

(Comparative Example 2)
In the battery state detection device of Comparative Example 2, the CPU was caused to execute the battery state calculation routine shown in FIG. This battery state calculation routine differs from the battery state calculation routine of the first embodiment in that step 310 of FIG. 3 is omitted.

(test)
We selected three 75D26 lead batteries that were used for 50,000 km per year in a taxi for a regular car in Tokyo, and calculated the true values of SOC, SOH, and life expectancy. That is, first, each lead battery was discharged to 10.5 V at 11 A, and the true value of the remaining capacity was measured. Thereafter, 14V constant voltage charging was performed at a maximum current of 20A, and charging was stopped in 20 minutes after the voltage reached 14V. The battery was discharged again to 10.5V at 11A and the full charge capacity was measured. Using the true value of the remaining capacity and the value of the full charge capacity, the true value of SOC = 100% × remaining capacity / full charge capacity and the true value of SOH = 100% × full charge capacity / initial full charge capacity were calculated. After the above tests, the lead battery was re-installed in the original vehicle and continued to be used in conventional taxi services until the engine could not be started. The time from this re-mounting until the engine could not be started was taken as the actual value (true value) of the remaining life of the lead battery.

  Table 3 shows the calculation results by the personal computer 8 of the SOC (%), SOH (%), and life expectancy (days) of the lead battery 75D26 first displayed on the notebook personal computer, their true value and deviation from the true value (%). Indicates.

  The value displayed on the display of the notebook personal computer by the battery state detection device of Example 1 substantially matched the true value. In the battery state detection devices of Comparative Examples 1 and 2, the SOC, SOH, and life expectancy of the battery state detection devices of Example 1 were significantly different from true values. Therefore, it turns out that the battery state detection apparatus of Example 1 is excellent.

  The present invention relates to a battery state detection device that can uniquely define the deterioration state of a battery even if the battery has deteriorated in various modes, and contributes to the manufacture and sale of the battery state detection device. Have potential.

It is explanatory drawing of the SOH map which shows the relationship between the discharge voltage and open circuit voltage in various SOH in 25 degreeC of a 75D26 lead battery. It is a schematic block diagram of the battery state detection apparatus of embodiment to which this invention is applied. It is a flowchart of the battery state calculation routine which CPU of the battery state detection apparatus of embodiment performs. It is a flowchart of the battery state calculation routine which CPU of the battery state detection apparatus of the comparative example 1 performs. 12 is a flowchart of a battery state calculation routine executed by a CPU of the battery state detection device of Comparative Example 2. It is explanatory drawing which shows typically the waveform of the electric current which flows into the lead battery at the time of engine starting.

Explanation of symbols

1 Lead battery (battery)
8 Microcomputer 11 Battery state detection device

Claims (7)

In the battery state detection device for detecting the state of the battery,
A first SOH decrease amount calculating means for calculating an amount of decrease in SOH of the battery in a fully charged state;
A second SOH decrease amount calculating means for calculating a decrease amount of the SOH of the battery when the voltage of the battery due to high rate discharge is equal to or lower than a predetermined value;
SOH calculating means for calculating the SOH value of the battery from both of the SOH reduction amounts calculated by the first and second SOH reduction amount calculating means;
A battery state detection device comprising:   2. The battery state detection device according to claim 1, wherein the first and second SOH decrease amount calculating means calculates the decrease amount of the SOH from an open circuit voltage, an internal resistance, or a discharge voltage of the battery. .   The first SOH decrease amount calculating means calculates the SOH decrease amount from an open circuit voltage of the battery in a fully charged state, and the second SOH decrease amount calculating means increases the internal resistance of the battery. The battery state detection device according to claim 2, wherein a decrease amount of the SOH is calculated from a value.   The battery state detection device according to claim 1, further comprising life expectancy calculating means for calculating the life expectancy of the battery from a plurality of values of the SOH at different times calculated by the SOH calculating means.   5. The battery state detection device according to claim 4, wherein the life expectancy calculating means calculates the life expectancy of the battery from a progress speed of the deterioration state of the battery.   SOC calculation means for calculating the SOC value of the battery in a non-full charge state, SOC value calculated by the SOC calculation means, and SOH of the battery calculated by the second SOH reduction amount calculation means The battery state detection device according to claim 1, further comprising a charge state calculation unit that calculates a charge state of the battery based on a decrease amount and the SOH calculated by the SOH calculation unit.   The battery state detection device according to claim 6, wherein the SOC calculation unit calculates the SOC value of the battery in a non-full charge state from the open circuit voltage, internal resistance, or discharge voltage of the battery.