DE112017001422T5 - Battery state estimator - Google Patents

Abstract

A battery state estimator is provided, whereby the accuracy of calculating a battery state of charge can be prevented from being deteriorated. The battery state estimator 110 includes an SOCv calculation unit 111 configured to calculate SOCv using the voltages at the opposite ends of a battery, an SOCi calculation unit 112 configured to add SOCi by integrating the current flowing in the battery and a first and second temperature processing unit 115, 116 into which a plurality of temperatures at different measurement positions of the battery are input, which are configured to set a first temperature T1 and a second temperature T2 based on the plurality of temperatures, SOCw calculated by weighting and adding SOCv and SOCi. At this time, the weighting of SOCi is changed in association with the absolute value of the difference between the first temperature T1 and the second temperature T2.

Description

Technical area

The present invention relates to a battery state estimator.

Technical background

Devices using a power storage unit such as a lithium secondary battery, a nickel hydrogen battery, a lead battery, an electric double layer capacitor, or the like are, for example, a battery system, a distributed power storage device, an electric vehicle, and the like. In the above-mentioned devices, a state detection circuit for detecting the state of the power storage unit is used to securely and efficiently use the power storage unit. States of the current storage unit are a state of charge (hereinafter referred to as "SOC") indicating how much electric charge is charged or how much removable electric charge remains, a functional state (hereinafter referred to as "SOH") indicating how much an occurring one Deterioration is, and the like.

The SOC in the battery system for a portable device, an electric vehicle, or the like can be detected by integrating the discharge current from a full charge to increase the ratio between the amount of electric charge remaining in the electric storage unit (residual capacity) and the electric charge amount (total capacity) at maximum charge to calculate. The SOC obtained in this way is called SOCi. Further, apart from the SOCi, the relationship between the voltages at the opposite ends of the battery (open circuit voltage) and the remaining capacity of the battery is previously defined in a data table or the like, and then the current remaining capacity can be calculated from the aforementioned data table. The SOC obtained in this way is called SOCv. In addition, the state of charge can be obtained by combining the above-mentioned methods. For example, in JP-A-2010-256323 (PTL 1) described that weights of SOCi and SOCv are determined depending on the use state of the power storage unit in combination of SOCi and SOCv.

The open circuit voltage of the battery can be obtained by performing a measurement when the battery is in a stable state after a time has elapsed since the charging and discharging of the battery is interrupted. However, because an IR drop generated by charging and discharging (current × DC of internal resistance) and a polarization voltage are generated during operation of the battery system, it is difficult to directly measure the open circuit voltage. Therefore, the IR drop and the polarization voltage are estimated based on the measurement of amounts of voltage (closed circuit voltage), the current flowing in the battery, the battery temperature, and the like during the operation of the battery system. In this way, a method is generally used in which the open circuit voltage is obtained by subtracting the obtained IR drop and the polarization voltage from the closed circuit voltage to calculate the state of charge.

quote list

patent literature

PTL 1: JP-A-2010-256323

Summary of the invention

Technical problem

It is known that IR drop and polarization voltage characteristics are significantly dependent on the temperature of the battery. Depending on the shape and material of the battery, the temperature may not be uniform but distributed, or the temperature distribution may change as a result of charging and discharging during operation of the battery system. If the temperature of the battery is not uniform, a unique battery temperature can not be obtained, and if the temperature difference therebetween is large, it becomes difficult to accurately estimate the IR drop and the polarization voltage. In this case, an error may occur in the calculation of the state of charge because a correct open circuit voltage can not be obtained.

the solution of the problem

According to one aspect of the present invention, a battery state estimating apparatus includes: a first calculating unit configured to calculate a first state of charge by using the voltages of the opposite ends of a battery; a second calculating unit configured to integrate a second state of charge by integrating of the current flowing in the battery, a third calculating unit configured to calculate the state of charge of the battery by weighting and adding the first state of charge and the second state of charge, and a temperature processing unit to which plural temperatures are input at different measuring positions of the battery , the is configured to set a first and a second temperature based on the plurality of temperatures, wherein the third calculation unit changes the weight of the second state of charge in association with the absolute value of the difference between the first temperature and the second temperature.

Advantageous Effects of the Invention

According to the present invention, the accuracy of calculating the battery state of charge can be prevented from deteriorating.

list of figures

• 1 ein Blockdiagramm einer Konfiguration eines Batteriesystems,
• 2 ein Funktionsblockdiagramm von Einzelheiten einer Batteriezustands-Schätzvorrichtung,
• 3 ein Diagramm eines Ersatzschaltbilds einer Batterie,
• 4 ein Diagramm einer Beziehung zwischen OCV und SOC,
• 5 ein Diagramm einer Beziehung zwischen dem Innenwiderstand der Batterie und ihrer Temperatur,
• 6 ein Diagramm eines Beispiels eines Korrekturkoeffizienten,
• 7 ein Diagramm eines Verfahrens zum Festlegen eines Korrekturkoeffizienten gemäß einer zweiten Ausführungsform,
• 8 ein Diagramm eines Verfahrens zum Festlegen eines Korrekturkoeffizienten gemäß einer dritten Ausführungsform,
• 9 ein Diagramm eines Verfahrens zum Festlegen eines Korrekturkoeffizienten gemäß einer vierten Ausführungsform,
• 10 ein Diagramm, das eine fünfte Ausführungsform beschreibt,
• 11 ein Diagramm einer Modifikation der fünften Ausführungsform,
• 12 ein Diagramm einer ersten Temperaturberechnungseinheit und einer zweiten Temperaturberechnungseinheit gemäß einer sechsten Ausführungsform,
• 13 ein Diagramm eines Beispiels von Messpositionen und
• 14 ein Diagramm eines anderen Beispiels einer ersten Temperaturberechnungseinheit und einer zweiten Temperaturberechnungseinheit.

Show it:

• 1 a block diagram of a configuration of a battery system,
• 2 FIG. 4 is a functional block diagram showing details of a battery state estimating device; FIG.
• 3 a diagram of an equivalent circuit diagram of a battery,
• 4 a diagram of a relationship between OCV and SOC,
• 5 a diagram of a relationship between the internal resistance of the battery and its temperature,
• 6 a diagram of an example of a correction coefficient,
• 7 FIG. 2 is a diagram of a method of setting a correction coefficient according to a second embodiment; FIG.
• 8th FIG. 4 is a diagram of a method of setting a correction coefficient according to a third embodiment; FIG.
• 9 FIG. 4 is a diagram of a method of setting a correction coefficient according to a fourth embodiment; FIG.
• 10 a diagram describing a fifth embodiment,
• 11 a diagram of a modification of the fifth embodiment,
• 12 1 is a diagram of a first temperature calculation unit and a second temperature calculation unit according to a sixth embodiment,
• 13 a diagram of an example of measuring positions and
• 14 a diagram of another example of a first temperature calculation unit and a second temperature calculation unit.

Description of embodiments

First Embodiment

1 FIG. 13 is a diagram showing a first embodiment of the present invention, and is a block diagram illustrating a configuration of a battery system. FIG 1000 shows. The battery system 1000 leads an external device in a battery 400 stored electric charge as electric power and has a battery control device 100 , a measurement unit 200 and an output unit 300 on. For example, an electric vehicle, a hybrid vehicle, a train and the like are regarded as destinations to which the battery system supplies the electric power.

The battery 400 is, for example, a rechargeable battery such as a lithium ion secondary battery. Further, the present invention can also be applied to devices having a power storage function such as a nickel hydrogen battery, a lead battery, an electric double layer capacitor, and the like. The battery 400 For example, a single battery cell or a module structure in which a plurality of individual battery cells are combined with each other may be.

The measuring unit 200 is a functional unit, the physical properties of the battery 400 measures, for example, the tensions V the opposite ends of the battery 400 in the battery 400 flowing electricity (battery current) I , Temperatures t1 and t2 the battery 400 and the like, and it is provided with a sensor for measuring each value, a required electric circuit, and the like. According to the embodiment, the measuring unit 200 Temperatures at two different positions of the battery 400 measure, where t1 a temperature detected at a first measuring position is and t2 is a detected at a second measurement position temperature. Further, as will be described later, the internal resistance R the battery 400 However, in order to estimate the battery state, according to the embodiment, the estimation of the battery state is made using other measurement parameters in a battery state estimator 110 calculated.

The output unit 300 is a functional unit that is an output of the battery controller 100 to an external device (for example, a host device such as a Vehicle control device and the like included in an electric vehicle).

The battery control device 100 is a device that controls the operation of the battery 400 controls, and the battery state estimator 110 and a storage unit 120 on.

The battery condition estimator 110 calculates the SOC of the battery 400 based on the tensions V the opposite ends, the battery current I and the battery temperatures t1 and t2 , all from the measurement unit 200 be measured, and in the storage unit 120 stored characteristic information of the battery 400 , Details of an SOC calculation method will be described later.

The storage unit 120 stores the characteristic information of the battery 400 that can be known in advance, in the type of internal resistance R , the polarization voltage Vp, the charging efficiency, the allowable current, the total capacity, and the like. The characteristic information may be stored such that a value can be stored individually for each charging and discharging process, or for each state of the battery 400 in the nature of the state of charge and the temperature, a value can be stored individually or all states of the battery 400 common value can be stored.

The battery control device 100 and the battery condition estimator 110 can be formed by using hardware such as a circuit device and the like, thereby realizing functions thereof. Further, software in which these functions are realized can be executed by a computing device such as a CPU (central processing unit). In the latter case, the software is stored in the memory unit, for example 120 saved.

The storage unit 120 is formed using a memory device such as a flash memory, an EEPROM (Electrically Erasable Programmable Read Only Memory), and a magnetic disk. The storage unit 120 can outside the battery condition estimator 110 or as one in the battery state estimator 110 recorded storage device be realized. The storage unit 120 can be removable. If the storage unit 120 is removable, the characteristic information and the software can be easily replaced by the storage unit 120 be changed. Further, the characteristic information and software for each small unit can be updated by storing multiple memory parts 120 provided and the characteristic information and software distributed in the removable storage units 120 get saved.

2 FIG. 12 is a functional block diagram showing details of the battery condition estimator. FIG 110 shows. The battery condition estimator 110 has an SOCv calculation unit 111 , a SOCi calculation unit 112 , an IR calculation unit 113 , a weight calculation unit 114 , a first temperature calculation unit 115 and a second temperature calculating unit 116 and outputs the state of charge SOCw by estimating the state of charge of the battery 400 results. Other calculation devices will be described later.

The SOCv calculation unit 111 calculates the SOC of the battery 400 using the from the measurement unit 200 measured voltages V the opposite ends of the battery 400 , The following is the one of the SOCv calculation unit 111 calculated SOC referred to as SOCv. The SOCi calculation unit 112 calculates the SOC of the battery 400 by integrating the from the measuring unit 200 measured battery current I the battery 400 , Below is the one from the SOCi calculation unit 112 calculated SOC referred to as SOCi. Calculation methods for the SOCv and the SOCi will be described later. The IR calculation unit 113 multiplies the battery current I with the internal resistance R , A method for obtaining the internal resistance R will be described later, wherein the internal resistance R based on a resistance table based on that of the first temperature calculation unit 115 entered first temperature T1 is obtained.

In addition, the SOCv calculation unit 111 and the IR calculation unit 113 According to the embodiment, it is configured to perform respective processing using the one of the first temperature calculating unit 115 entered first temperature T1 as temperature information. Alternatively, for example, instead of the first temperature T1 or the second temperature T2 the average from the first temperature T1 and the second temperature T2 be used.

The weight calculation unit 114 calculates a weight W for weighting and adding SOCv and SOCi based on two types of temperature with respect to the battery 400 that of the first temperature calculation unit 115 output first temperature T1 and that of the second temperature calculating unit 116 output second temperature T2 , A method of calculating the weight W will be described later. The first Temperature calculating unit 115 gives the at a first measuring position of the battery 400 recorded temperature t1 as the first temperature T1 out. The second temperature calculation unit 116 gives the at a second measuring position of the battery 400 recorded temperature t2 as a second temperature T2 out.

A multiplier MP1 obtains WxSOCv by multiplying SOCv by weight W. A subtractor DF receives (1 - W). A multiplier MP2 obtain (1-W) × SOCi by multiplying SOCi by (1-W). An adder AD obtains SOCw by adding W × SOCv and (1-W) × SOCi. In particular, SOCw is represented by the following equation (1): $$\text{SOCw}=\text{W}\times \text{SOCv}+\left(1-\text{W}\right)\times \text{Soci}$$

[Operation of SOCv Calculation Unit 111]

Next, the operation of the SOCv calculation unit 111 described. 3 is an equivalent circuit diagram of the battery 400 , The battery 400 can by a series connection of a parallel circuit pair of an impedance Z and a capacitance component C , the internal resistance R and an open circuit voltage OCV be represented. When the battery power I to the battery 400 is applied, a closed circuit voltage CCV, which is the voltage between the terminals of the battery 400 is represented by the following equation (2). In Equation (2), Vp is the polarization voltage and corresponds to the voltages of the opposite ends of the parallel pair from the impedance Z and the capacitance component C , $$\text{CCV}=\text{OCV}+1\cdot \text{R}+\text{vp}$$

The open circuit voltage OCV is used to calculate SOCv, but can not be measured directly while the battery is running 400 is loaded and unloaded. Here is the SOCv calculation unit 111 the open circuit voltage OCV by subtracting the IR drop and the polarization voltage Vp from the closed circuit voltage CCV, as represented in the following equation (3): $$\text{OCV}=\text{CCV}-\text{IR}-\text{vp}$$

The internal resistance R and the polarization voltage Vp beforehand as characteristic information in the memory unit 120 saved. Because the internal resistance R and the polarization voltage Vp from the state of charge, the temperature and similar conditions of the battery 400 depending on their respective combinations, an individual value in the memory unit 120 saved. According to the embodiment, the characteristic information showing a correspondence relationship between the internal resistance R and the battery temperature T, stored as a resistance table. As in 2 is shown receives the SOCv calculation unit 111 the internal resistance R of the resistance table based on that of the first temperature calculating unit 115 entered first temperature T1 ,

4 FIG. 12 is a diagram showing a relationship between the open circuit voltage OCV and the SOC of the battery 400 shows. Their correlation is determined by the characteristics of the battery 400 and data defining the correspondence relationship between them are preliminarily set as a SOC table in the storage unit 120 saved. The SOCv calculation unit 111 calculates the open circuit voltage OCV using equation (3) and calculates the SOCv of the battery 400 with reference to the SOC table using the open circuit voltage OCV as a key.

[Operation of SOCi Calculation Unit 112]

Next, the operation of the SOCi calculation unit 112 described. The SOCi calculation unit 112 gets the SOCi of the battery 400 by integrating the from the battery 400 absorbed and discharged battery current I according to the following equation (4). In equation (4), Qmax is the total charge capacity of the battery 400 and is pre-recorded in the storage unit 120 saved.

SOCold is a value of SOCw calculated in a previous calculation period according to Equation (1). $$\text{Soci}=\text{socold}+100\times {\displaystyle \int \text{I}/\text{Qmax}}$$

[Operation of Weight Calculation Unit 114]

5 is a diagram showing a relationship between the internal resistance R and the temperature T of the battery 400 shows. In general, as in 5 is shown in the battery 400 the internal resistance R is high in a state of low SOC and is the value of internal resistance R high in a low temperature state. Therefore, it is considered that in such cases it is desirable to use SOCi instead of SOCv, which is easily affected by an internal resistance R error. Furthermore, it is assumed that with a small absolute value of the battery current I it is desirable not to use SOCi but to use SOCv because an influence by a slight measurement error of a current sensor occurs.

Based on the above, the weight calculation unit sets 114 determine the weight W to calculate the SOCw value mainly using SOCv when the absolute value of the battery current I is low, and to calculate SOCw mainly using SOCi when the absolute value of the battery current I is high. In the same way, the weight W is set so that at a small internal resistance R mainly, the SOCv value is used to calculate SOCw, and when the internal resistance R is high, mainly the SOCi value is used to calculate SOCw.

Further, according to the embodiment, the weight W is calculated considering a temperature variation in the battery 400 set appropriately.

As in 5 is shown, the internal resistance depends R the battery 400 from the battery temperature T from. Further, as in the operation of the SOCv calculation unit 111 described, the internal resistance R calculated using the resistance table based on the battery temperature T.

Here, consider a case where the difference between the first temperature T1 at the first measuring position of the battery 400 and the second temperature T1 is high at the second measuring position. The one using the first temperature T1 and the resistance table calculated internal resistance is called internal resistance R1 defined, and that using the second temperature T2 and the resistance table calculated internal resistance is called internal resistance R2 Are defined. If the difference between the first temperature T1 and the second temperature T2 is great, there is a possibility that the difference between the internal resistance R1 and the internal resistance R2 is great. In this case, the true internal resistance R the battery 400 near a result of either the internal resistance R1 or internal resistance R2 or be a composite value of either, or be of a different value.

At an in 2 The example shown becomes the first temperature T1 into the SOCv calculation unit 111 entered. If the difference between the first temperature T1 and the second temperature T2 is large, however, it is difficult, as described above, the true internal resistance R the battery 400 to calculate exactly so that the error in calculating the internal resistance R gets high. If the error of calculation of internal resistance R is high, the open circuit voltage OCV calculated according to the equation (3) becomes inaccurate, which deteriorates the accuracy of the calculation of SOCv, and further, the accuracy of calculation of the SOCw calculated by the equation (1) may also deteriorate.

Here, according to the embodiment, the first temperature T1 and the second temperature T2 in the weight calculation unit 114 and the weight W is input using a correction coefficient Ktdiff corresponding to the absolute value Tdiff (= | T1-T2 |) of the difference between the first temperature T1 and the second temperature T2 is set according to the following equation (5). Further, the correction coefficient Ktdiff is set as a value between 0 and 1. As a guideline for setting the correction coefficient Ktdiff, when the absolute value Tdiff of the temperature difference is larger than a predetermined threshold Tdth, the correction coefficient Ktdiff is set to a smaller value to set the weight of SOCi to a higher value than when the absolute value Tdiff is the temperature difference is smaller than the predetermined threshold Tdth, by an error in the calculation of the internal resistance R to prevent deterioration of the accuracy of the calculation of SOCw. $$\text{W}=\text{Ktdiff}\times \text{1/}\left(1+\text{R}\cdot \left|\text{I}\right|\right)$$

6 shows an example of the correction coefficient Ktdiff, and a horizontal axis is the absolute value Tdiff of the difference between the first temperature T1 and the second temperature T2 , At an in 6 The example shown is set with respect to a predetermined threshold Tdth in the case of Tdiff <Tdth Ktdiff = 1 and set to approximately zero in the case of Tdiff ≥ Tdth Ktdiff.

The weight W at the time Tdiff ≥ Tdth is set to approximately zero according to Equation (5) by setting the correction coefficient Ktdiff in the aforementioned manner, thereby setting SOCw ≅ SOCi according to Equation (1).

That is, SOCw almost matches the case of SOCi calculation.

Because SOCi does not have the internal resistance R As shown in equation (4), SOCi receives even if the difference between the first temperature T1 and the second temperature T2 so big is that the error in the calculation of the internal resistance R does not get big, this influence. Accordingly, SOCw is established by introducing the correction coefficient Ktdiff as in 6 is shown when the difference between the first temperature T1 and the second temperature T2 is large, calculated using SOCi instead of SOCv, where there is a possibility that the computational accuracy deteriorates. Therefore, the accuracy of calculation of SOCw can be prevented from deteriorating.

Further, when the absolute value Tdiff of the temperature difference is smaller than the predetermined threshold value Tdth, the correction coefficient Ktdiff becomes 1, corresponding to the weight W, from the prior art disclosed in PTL 1, as shown in equation (6). That is, if the error in the calculation of internal resistance R can be ignored because the difference between the first temperature T1 and the second temperature T2 is small, the state-of-the-art SOCw calculation is applied so that there is no possibility that the behavior of SOCw and the computational accuracy are changed. $$\text{W}=1/\left(1+\text{R}\cdot \left|\text{I}\right|\right)$$

Further, in 6 if the correction coefficient Ktdiff is greater than or equal to the threshold value Tdth, the correction coefficient Ktdiff is set to approximately zero. Incidentally, in the case of a fixed value, where the specific gravity of SOCi becomes large in order to prevent the accuracy of calculation of SOCw from decreasing, the correction coefficient Ktdiff can not be approximately zero and further not a fixed but a variable value.

As described above, according to the embodiment, when SOCw is calculated by weighting and adding the SOCv calculated by the SOCv calculation unit and the SOCi calculated by the SOCi calculation unit, the weighting of SOCi is related to the magnitude of the absolute value Tdiff of the difference between the first temperature T1 and the second temperature T2 changed. In a prior art battery state calculation method using Equation (6), because the weight W is constant, although a temperature distribution is generated in the battery and thus the error in the calculation of SOCv is large, the error becomes in the calculation of SOCw according to the error in the calculation of SOCv also large. On the other hand, according to the embodiment, when a temperature difference occurs in the battery, because the weight of SOCi is changed in association with the absolute value Tdiff of the temperature difference, that is, because the weight W is changed by changing the correction coefficient Ktdiff in association with the amount of Tdiff Accordingly, as shown in equation (5), it is possible to reduce the influence of the arithmetic error from SOCv to SOCw. Therefore, the accuracy of calculation of SOCw can be prevented from deteriorating.

For example, as in 6 is shown when the absolute value Tdiff of the difference between the first temperature T1 and the second temperature T2 is greater than or equal to the predetermined threshold Tdth, the weighting of SOCi is set to a higher value than when the absolute value Tdiff is less than the predetermined threshold Tdth. In the case of Tdiff ≥ Tdth, where the influence caused by the error of SOCv is significant because Tdiff is set to almost zero, SOCw ≅ SOCi, thereby becoming almost equal to a case where it is calculated by the SOCi. If the error of calculation of internal resistance R the battery 400 becomes large, SOCw is accordingly calculated using SOCi in place of SOCv with the possibility of deterioration of the calculation accuracy, so that deterioration of the accuracy of calculation of SOCw can be prevented.

-Second embodiment-

7 FIG. 15 is a diagram showing a method of setting a correction coefficient Ktdiff according to a second embodiment. FIG.

According to the first embodiment described above, the correction coefficient Ktdiff depends on the absolute value Tdiff of the temperature difference. It depends, as in 7 is shown, the correction coefficient Ktdiff not only from the absolute value Tdiff of the temperature difference, but also from a temperature Tlow. In 7 the horizontal axis indicates the absolute value Tdiff of the temperature difference and the horizontal axis indicates the temperature Tlow. Here the temperature Tlow is the lower of the first temperature T1 and the second temperature T2 ,

At an in 7 For example, at temperature Tlow ranging from 0 ° C to -30 ° C, when the absolute value Tdiff of the temperature difference is at least 10 ° C, Ktdiff = 0 is set and Ktdiff = 1 when Tdiff <10 ° C. That is, this case corresponds to the case described above in which 6 the predetermined threshold Tdth = 10 ° C is set. On the other hand, when the temperature Tlow exceeds the predetermined threshold Tth (= 0 ° C), Ktdiff = 1 is set even if the absolute value Tdiff of the temperature difference is between 0 ° C and 20 ° C.

As in 5 is shown, the internal resistance depends R the battery 400 from the battery temperature T and is the value of the internal resistance R in a low temperature state, while the value of the internal resistance R is small when the battery temperature T is high. Therefore, although the difference between the first temperature T1 and the second temperature T2 is large, when the battery temperature T is high, the error at the calculation of the internal resistance R the battery 400 less than a low temperature condition. Accordingly, the weight W can be determined more suitably by setting the correction coefficient Ktdiff as an additional condition for the temperature Tlow with respect to the battery temperature.

That is, if the lower of the first temperature T1 and the second temperature T2 (ie Tlow) is less than or equal to the predetermined threshold Tth and the absolute value Tdiff is the difference between the first temperature T1 and the second temperature T2 is greater than or equal to the predetermined threshold value Tdth, because the correction coefficient Ktdiff is set to zero to increase the weighting of the SOCi, the weight W from equation (5) becomes W = 0, and SOCw is calculated by SOCi. However, under other conditions, the correction coefficient Ktdiff is set to 1, and SOCw having the weight W is calculated by the prior art equation (6). Therefore, the accuracy of calculation of SOCw can be prevented from deteriorating.

Furthermore, in 7 the correction coefficient Ktdiff is set to 0 or 1. Alternatively, Kdiffiff may not be 0 if the specific weighting of SOCi becomes large to prevent the accuracy of the calculation of SOCw from being degraded. Further, a value that prevents the accuracy of calculation of SOCw from being deteriorated may be set corresponding to values of the temperature Tlow and the correction coefficient Ktdiff as the correction coefficient Ktdiff.

Furthermore, in 7 applied on the vertical axis the temperature Tlow. Alternatively, the internal resistance Rhigh can be plotted on the vertical axis. In this case, the internal resistance Rhigh becomes the larger value of using the first temperature T1 and the resistance table calculated internal resistance R1 and from using the second temperature T2 and the resistance table calculated internal resistance R2 set. In this case, when the internal resistance Rhigh is greater than or equal to a predetermined threshold value Rth and the absolute value Tdiff of the temperature difference is greater than or equal to the predetermined threshold value Tdth, Ktdiff = 0 is set. Accordingly, it is possible to respond appropriately to characteristic changes in internal resistance caused by factors other than temperature.

Third embodiment

8th FIG. 15 is a diagram describing a method of setting a correction coefficient Ktdiff according to a third embodiment. FIG. According to the embodiment, when the absolute value Tdiff of the temperature difference is smaller than the predetermined threshold Tdth, the correction coefficient Ktdiff corresponding to the absolute value Tdiff of the difference between the first temperature T1 and the second temperature T2 changed. In the case of a line L0 in 8th Kdiff = 1 is set when the absolute value Tdiff of the temperature difference is approximately zero, Kdiffiff decreases when Tdiff becomes large, and Kdiffiff is set to approximately zero when Tdiff is equal to or greater than the predetermined threshold value Tdth.

As described above, the error of the internal resistance calculation becomes R the battery 400 big when the difference between the first temperature T1 and the second temperature T2 is great. If, on the other hand, the difference between the first temperature T1 and the second temperature T2 is small, is the error of the calculation of the internal resistance R small (see 5 ). According to the embodiment, in consideration of the above-mentioned characteristics, the correction coefficient Ktdiff (ie, the weight W) is set according to the absolute value Tdiff of the temperature difference. If at the in 8th illustrated line L0 If the absolute value Tdiff of the temperature difference is smaller than the predetermined threshold value Tdth, the correction coefficient Ktdiff is set so that the specific gravity of SOCi becomes large as the absolute value Tdiff of the temperature difference becomes large.

If the error of calculation of internal resistance R of the battery 400 becomes large, SOCw is therefore calculated by emphasizing SOCi versus SOCv, where the possibility of deterioration of the calculation accuracy may occur. On the other hand, if the error of the calculation of the internal resistance R is small (Tdiff ≅ 0), Ktdiff = 1 and SOCw is calculated according to Equation (6) for the weight W of the prior art. As described above, because the SOCw calculation can be made by appropriately using SOCi corresponding to the amount of error in the calculation of the internal resistance R is executed, a deterioration of the accuracy of the calculation of SOCw can be prevented.

Furthermore, in the case of 8th illustrated line L0 the absolute value Tdiff of the temperature difference is set to approximately zero when the absolute value Tdiff of the temperature difference is greater than or equal to the predetermined threshold value Tdth. Alternatively, Ktdiff can be set to approach asymptotically zero as Tdiff grows large, as in the line L1 is shown.

- Fourth embodiment

9 FIG. 15 is a diagram showing a method of setting the correction coefficient Ktdiff according to a fourth embodiment. FIG. According to the embodiment, the predetermined threshold Tdth with respect to that in the 6 to 8th shown correction coefficient Ktdiff corresponding to the degree SOH of deterioration of the battery 400 changed. At an in 9 For example, when the degree SOH of deterioration of the battery is decreased, the predetermined threshold Tdth is decreased 400 gets bigger.

In general, when the degree SOH of deterioration of the battery is large, the internal resistance becomes high. Accordingly, as the degree SOH of deterioration of the battery becomes larger, the error of the internal resistance calculation becomes R the battery 400 becomes larger, and the open circuit voltage OCV calculated by equation (3) becomes inaccurate. Thereby, the accuracy of the calculation of SOCv deteriorates, and there is the possibility that the accuracy of calculation of the SOCw calculated by the equation (1) deteriorates.

According to the embodiment, in order to prevent the accuracy of the calculation of SOCw from being degraded by the deterioration degree SOH, the predetermined threshold value Tdth is decreased when the degree SOH of deterioration of the battery 400 increases. Therefore, as the SOH deteriorates from SOH to SOH1 (SOH → SOH1) °, as in 9 and hence the error of calculating the internal resistance R increases, the default threshold Tdth changed to Tdth1, and the in 8th illustrated line L0 becomes a broken line, for example L2 changed.

Accordingly, when the deterioration degree SOH increases, the predetermined threshold value Tdth is decreased, whereby even if the absolute value Tdiff of the temperature difference is small, the absolute value Tdiff of the temperature difference becomes equal to or greater than the predetermined threshold value Tdth, so that the correction coefficient Ktdiff becomes approximately zero , Therefore, the weight W becomes approximately zero, and SOCw is calculated using SOCi instead of SOCv, with the possibility that the calculation accuracy deteriorates, so that the accuracy of calculation of SOCw can be prevented from deteriorating.

In a method in which the degree SOH of deterioration of the battery 400 is estimated, a deterioration degree calculation unit in the battery state estimator 110 a degradation degree information signal from another with the battery state estimator 110 connected device or the two aforementioned methods are combined.

- Fifth embodiment -

10 a diagram showing a fifth embodiment. 10 shows the first temperature calculation unit 115 and the second temperature calculation unit 116 the battery condition estimator 110 , According to the embodiment, the battery 400 three temperature measuring positions and become a temperature t1 at the first measuring position, a temperature t2 at the second measuring position and a temperature t3 at the third measuring position of the measuring unit 200 in the battery condition estimator 110 entered. The temperatures t1 to t3 are each in the first temperature calculation unit 115 and the second temperature calculation unit 116 entered.

The first temperature calculation unit 115 chooses the highest of the temperatures t1 . t2 and t3 off and gives the temperature as the first temperature T1 out. On the other hand, the second temperature calculation unit selects 116 the lowest of the temperatures t1 . t2 and t3 off and gives the temperature as the second temperature T2 out. The weight calculation unit 114 sets the weighting of SOCv based on the absolute value Tdiff of the difference between the highest temperature output (first temperature T1 ) and the lowest temperature (second temperature T2 ) firmly.

For example, according to the above configuration, although a distribution is generated, the temperature becomes dependent on the shape and the material of the battery 400 is not uniform or the temperature distribution when charging and discharging the battery system 1000 During operation, the highest temperature changes from the temperatures at several positions as the first temperature T1 selected and the lowest temperature of these as the second temperature T2 selected, which makes it possible to change the characteristics of the battery 400 suitable to capture. If the difference between the first temperature T1 and the second temperature T2 is large, SOCw is calculated by using SOCi instead of SOCv in which there is a possibility that the accuracy of the calculation is deteriorated, so that the accuracy of calculation of SOCw can be prevented from being deteriorated.

(Modification)

11 Fig. 16 is a diagram showing a modification of the fifth embodiment. At an in 10 The example shown gives the first temperature calculation unit 115 the highest of the temperatures t1 . t2 and t3 as the first temperature T1 out. At the in 11 however, the modification shown becomes the average of the temperatures t1 . t2 and t3 calculates and gets the average temperature as the first temperature T1 output.

According to the embodiment, the first temperature T1 to the average temperature and becomes the second temperature T2 At the lowest temperature, however, because the average temperature is midway between the highest temperature and the lowest temperature, the characteristics of the battery can be determined 400 as well as in 10 can be suitably detected even when using the method in which the average temperature and the lowest temperature are used.

Furthermore, in the 10 and 11 the number of temperature measuring positions of the battery 400 set to three, but this number can be set freely to a value of two or greater. Further, the same effect can be obtained even if it is determined that the highest temperature is detected by the second temperature calculating unit 116 out 11 is selected.

-Second embodiment-

The 12 to 14 Figures are diagrams showing a sixth embodiment. According to the sixth embodiment, as in 12 is shown, selects the first temperature calculation unit 115 the highest of the temperatures t1 . t2 and t3 off and gives the temperature as the first temperature T1 out. On the other hand, the second temperature calculation unit selects 116 the lowest of the temperatures t4 and t5 off and gives the temperature as the second temperature T2 out.

13 is a diagram showing an example of measuring positions of the temperatures t1 to t5 shows. A cooling plate 401 , which is a heat transfer with the battery 400 is adjacent to the battery 400 provided. At three measuring positions of the battery 400 recorded temperatures are called temperature t1 . t2 respectively. t3 defined, and at two measuring positions of the cooling plate 401 recorded temperatures are called temperature t4 or temperature t5 Are defined.

As described above, the internal resistance depends R the battery 400 from the battery temperature T from. If it is adjacent to the battery 400 an element (cooling plate 401 ) is due to the heat transfer between the element and the battery 400 a temperature distribution in the battery 400 generates and becomes the internal resistance R the battery 400 influenced by the temperature of the adjacent element. In such a case, there is the possibility that the internal resistance R the battery 400 can not be obtained suitably, unless the temperature of the heat transfer with the battery 400 exporting element as well as the temperature of the battery 400 be taken into account.

For example, to improve the input and output characteristics of the battery 400 and for preventing deterioration and ignition by overheating even if the battery 400 Heat generated because it is charged and discharged, assumed that the cooling plate 401 on the battery 400 attached, as in 13 is shown. The temperature of the battery 400 can by installing a pipe for supplying cooling water to the cooling plate 401 and for circulating the cooling water.

In this case, the temperature of the cooling plate 401 lower than the temperature of the battery 400 and will the heat of the cooling plate 401 transferred to a place where the battery 400 the cooling plate 401 touched, so the temperature of the battery 400 is lowered. When the measuring positions for the temperature t1 , the temperature t2 and the temperature t3 the battery 400 are separated from a place at which these measurement positions the cooling plate 401 can touch, the influence of the cooling plate 401 on the temperature of the battery 400 but not recorded.

In such a configuration as in 12 is shown, the lowest of the temperatures t4 and t5 the cooling plate 401 selected and as the second temperature T2 output, reducing the characteristics of the battery 400 can be suitably detected. If the difference between the first temperature T1 indicating the temperature of the battery 400 is, and the second temperature T2 indicating the temperature of the cooling plate 401 is large, SOCw is calculated using SOCi in place of SOCv in which the possibility of deterioration of the calculation accuracy occurs, so that the accuracy of calculation of SOCw can be prevented from being deteriorated.

Furthermore, in 13 an example shown, in which temperatures at three measuring positions of the battery 400 However, any number of measurement positions can be provided as long as their number is at least two. Further, an example is shown in which the Temperatures at two measuring positions of the cooling plate 401 However, one or three or more measuring positions may also be present.

Furthermore, in 13 an element that allows heat transfer with the battery 400 performs, as a cooling plate 401 However, any element can be used as long as it is connected to the battery 400 adjoins and the heat transfer with the battery 400 performs. For example, an element may be used for heating in place of the cooling plate and may be a cover of one in the battery 400 provided battery unit can be used. In a configuration where the element (cooling plate 401 or element for heating) that carries out the heat transfer, is cooled or heated by a fluid, the temperature of the heat transfer with the battery 400 exporting fluid can be used. Further, in a configuration having a cooling fan and a heating fan, the temperature of the air blown by the cooling fan and the heating fan may be detected.

In addition, as with a configuration off 14 is shown, the first temperature calculation unit 115 the highest of the temperatures t1 . t2 . t3 . t4 and t5 select and can the second temperature calculation unit 116 the lowest of the temperatures t1 . t2 . t3 . t4 and t5 choose. Accordingly, the highest and the lowest temperatures can be suitably detected even if the temperature of the battery 400 or the temperature of the battery 400 adjacent element is high. That is, the characteristics of the battery 400 can be suitably detected when the adjoining element is provided for cooling or heating, whereby the accuracy of calculation of SOCw can be prevented from being deteriorated.

Although various embodiments and modifications have been described above, the present invention is not limited thereto. Other embodiments than contemplated within the scope of the technical ideas of the present invention are also included within the scope of the present invention.

LIST OF REFERENCE NUMBERS

100:

Battery control device

110:

Battery state estimator

111:

SOCv calculation unit

112:

SOCI calculation unit

113:

IR calculation unit

114:

Weight calculating unit

115:

first temperature calculation unit

116:

second temperature calculation unit

120:

storage unit

200:

measuring unit

300:

output unit

400:

battery

401:

cooling plate

1000:

battery system

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2010256323 A [0003, 0005]

Claims (8)

A battery state estimator comprising: a first calculation unit configured to calculate a first state of charge by using the voltages of the opposite ends of a battery, a second calculation unit configured to calculate a second state of charge by integrating the current flowing in the battery; a third calculation unit configured to calculate the state of charge of the battery by weighting and adding the first state of charge and the second state of charge, and a temperature processing unit into which a plurality of temperatures at different measuring positions of the battery are input, which is configured to set a first and a second temperature on the basis of the plurality of temperatures, wherein the third calculating unit changes the weighting of the second state of charge in association with the absolute value of the difference between the first temperature and the second temperature. Battery condition estimator after Claim 1 wherein if the absolute value of the difference between the first temperature and the second temperature is greater than or equal to a first threshold, the third calculation unit sets the weight of the second state of charge to a higher value than if the absolute value is less than the first threshold. Battery condition estimator after Claim 2 wherein if the absolute value is greater than or equal to the first threshold and the first or second temperature is less than or equal to a second threshold, the third calculation unit sets the weight of the second state of charge to a high value. Battery condition estimator after Claim 2 or 3 wherein when the absolute value is smaller than the first threshold, the third calculation unit sets the weight of the second state of charge to a high value when the absolute value is large. Battery condition estimator after Claim 2 or 3 wherein the third calculation unit sets the first threshold to a small value when the degree of deterioration of the battery is large. Battery condition estimator according to one of Claims 1 to 3 wherein the temperature processing unit sets the highest of the plurality of temperatures as the first temperature and sets the lowest of the plurality of temperatures as the second temperature. Battery condition estimator according to one of Claims 1 to 3 wherein the temperature processing unit sets the average of the plurality of temperatures as the first temperature and sets the highest or the lowest of the plurality of temperatures as the second temperature. Battery condition estimator according to one of Claims 1 to 3 wherein temperatures are input to the temperature processing unit at plural positions of the battery and the temperature of an element or a fluid, whereby heat transfer is performed to the battery, and the temperature processing unit is the highest, the lowest, or the average temperature of the temperatures at the plurality of positions sets as the first temperature and determines the temperature or temperature related to the element or the fluid as the second temperature.

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