JP2018170144A - Battery temperature estimation device and method, and battery state estimation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide battery temperature estimation device and method for accurately estimating the battery temperature to use in battery state estimation, and to provide a battery state estimation device for estimating the soundness (SOH) of a battery by using the estimated temperature.SOLUTION: A battery temperature estimation device includes a pack's internal temperature detector 9, a battery temperature detector 11, a current detector 13, an internal resistance estimation part 17, and a temperature equivalent circuit model 21 of battery. The battery temperature estimation device further includes a battery temperature estimation part 19 for estimating the internal temperature of the battery by using a Kalman filter 23 and the temperature equivalent circuit model, on the basis of the internal temperature of the battery pack detected in the pack's internal temperature detector, the outer surface part temperature of the battery detected in the battery temperature detector, and the current detected in the current detector and the internal resistance of the battery estimated in the internal resistance estimation part.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a battery temperature estimation device and method, and a battery state estimation device, and more particularly, to a temperature estimation device and method for a driving battery used in an electric vehicle, and the battery state estimation device.

  The battery state indicates a charge rate (SOC: State of Charge), a soundness level (SOH: State of Health), and the like, and various proposals have been made as methods for estimating them. In this battery state estimation, the battery temperature is known as a parameter that greatly affects the SOC and SOH.

  For example, Patent Document 1 discloses a secondary battery charging rate estimation device, and in claim 4, the estimation device includes a plurality of open circuit voltages based on temperature detection values from a means for detecting the temperature of the secondary battery. It is shown that an inferior open circuit voltage estimating means among the estimating means is judged and initialized.

  Further, Patent Document 2 discloses a secondary battery deterioration state estimation device. Claim 1 includes temperature detection means for detecting the temperature of the secondary battery, and detects the time when the previous SOC was detected and the current SOC. It is shown that the storage deterioration state indicating the deterioration that occurs with time of the secondary battery is calculated based on the elapsed time from the detected time, the average SOC, and the detected temperature detected by the temperature detecting means.

  Further, Patent Literature 3 discloses a battery state estimation method and apparatus, and stores a SOH estimation table configured by SOH values corresponding to various internal resistances for each temperature and each SOC in a memory unit, and SOH estimation Upon request, measure temperature, estimate battery SOC, detect battery internal resistance, measure temperature, estimated battery SOC, and SOH value for detected battery internal resistance. Reading from the SOH estimation table.

Japanese Patent No. 3747826 Japanese Patent Laying-Open No. 2015-158416 Special table 2009-500603 gazette

  As the temperature data referred to in the methods disclosed in Patent Documents 1, 2, and 3 described above, the value of a temperature sensor installed in the battery pack is generally used. However, the battery pack is equipped with a cooling / heating device for temperature adjustment, and a cooling / heating device that circulates cold or hot air, a method that circulates liquid as a heat medium, or the like is known.

  In such a battery pack equipped with an air conditioner, the value indicated by the temperature sensor installed in the battery may deviate from the actual battery temperature, resulting in inaccurate battery temperature, and the accuracy of SOH estimation decreases. There is a problem to do.

  For example, in the case of a system in which cold air / hot air is circulated, cold air / hot air hits the installation position of the sensor and indicates a sensor value affected by the wind as well as the temperature of the battery. On the other hand, in the case of using a liquid as a heat medium, the temperature is adjusted by bringing the battery cell into contact with a water jacket through which the liquid passes. The battery temperature sensor indicates a sensor value affected by the temperature of the liquid in the water jacket and the temperature of the air around the sensor, in addition to the battery temperature.

  Accordingly, in view of the above technical problem, at least one embodiment of the present invention provides a battery temperature estimation device and method for accurately estimating a battery temperature used for battery state estimation, and a battery health level using the estimated temperature. It aims at providing the battery state estimation apparatus which estimates (SOH).

  (1) The present invention has been made to solve the above-described problems, and a battery temperature estimation device according to at least one embodiment of the present invention includes an in-pack temperature detection unit that detects an internal temperature of a battery pack in which a battery is accommodated. A battery temperature detection unit that is installed in the battery and detects an outer surface temperature of the battery, a current detection unit that detects a charge / discharge current of the battery, an internal resistance estimation unit that estimates an internal resistance of the battery, and a thermal resistance And the battery temperature equivalent circuit model having the heat capacity as a parameter, the internal temperature of the battery pack detected by the in-pack temperature detection unit, the external surface temperature of the battery detected by the battery temperature detection unit, and the current detection unit Based on the current and the internal resistance of the battery estimated by the internal resistance estimation unit, using the temperature equivalent circuit model, A battery temperature estimation unit for estimating the internal temperature of the battery by Le Mans filter, characterized in that it comprises a.

  According to the configuration (1), the internal temperature of the battery pack detected by the in-pack temperature detecting unit, the external surface temperature of the battery detected by the battery temperature detecting unit, the current detected by the current detecting unit, and the internal resistance estimating unit Since the battery temperature estimation unit for estimating the internal temperature of the battery by the Kalman filter is provided using the temperature equivalent circuit model based on the internal resistance of the battery, the internal temperature of the battery can be accurately estimated. Thereby, the estimation accuracy of the battery health (SOH) can be improved.

  (2) In some embodiments, the battery temperature estimator includes a state equation having an external surface temperature of the battery, an internal temperature of the battery pack, and an internal temperature of the battery as state variables, and an external surface temperature of the battery. The state variable is sequentially estimated based on the detected charge / discharge current by the Kalman filter from an observation equation having an observation value of the internal temperature of the battery pack as an observation variable.

  According to the configuration (2), an equation of state having the external surface temperature of the battery, the internal temperature of the battery pack, and the internal temperature of the battery as state variables, and the external surface temperature of the battery and the internal temperature of the battery pack The Kalman filter can be applied from the observation equation using the observation value as an observation variable, and the internal temperature of the battery can be estimated.

  (3) In some embodiments, the temperature equivalent circuit model includes an air-cooling temperature equivalent circuit model when the battery is cooled by cold air, and a liquid when the battery is cooled in contact with a refrigerant liquid. And a cooling temperature equivalent circuit model.

  According to the configuration (3), since the temperature equivalent circuit model includes the air cooling temperature equivalent circuit model and the liquid cooling temperature equivalent circuit model, an appropriate temperature equivalent circuit model corresponding to the battery cooling system is provided. Can be used to estimate the internal temperature of the battery.

  (4) A battery temperature estimation method according to at least one embodiment of the present invention includes an in-pack temperature detection step for detecting an internal temperature of a battery pack in which a battery is accommodated, and a battery temperature detection for detecting an external surface temperature of the battery. A step of detecting a charge / discharge current of the battery, an internal resistance estimating step of estimating an internal resistance of the battery, and a step of creating a temperature equivalent circuit model of the battery having thermal resistance and heat capacity as parameters Based on the internal temperature of the battery pack by the temperature detection step in the pack, the outer surface temperature of the battery by the battery temperature detection step, the current by the current detection step, and the internal resistance of the battery by the internal resistance estimation step. Using an equivalent circuit model, Kalman Phil Characterized in that it comprises a battery internal temperature estimation step of estimating the internal temperature of the battery by.

  According to the configuration (4), the internal temperature of the battery pack detected in the in-pack temperature detection step, the outer surface temperature of the battery detected in the battery temperature detection step, the current detected in the current detection unit, and the internal resistance estimation unit Since the battery internal temperature estimation step for estimating the internal temperature of the battery by the Kalman filter using the temperature equivalent circuit model based on the internal resistance of the battery is provided, the internal temperature of the battery can be accurately estimated. Thereby, the estimation accuracy of SOH can be improved.

  (5) A battery state estimation device according to at least one embodiment of the present invention includes the battery temperature estimation device according to any one of (1) to (3), and further, the battery state estimation device estimated by the battery temperature estimation device. An SOH estimating unit for estimating the SOH of the battery based on an internal temperature and an internal resistance estimated by the internal resistance estimating unit is provided.

  According to the configuration (5), since the battery internal temperature can be accurately estimated by the battery temperature estimating device, the estimation accuracy of the battery SOH can be improved.

  (6) In some embodiments, the SOH estimation unit has an SOH map in which a relationship between the internal temperature of the battery, the internal resistance, and the SOH is set in advance, and the SOH map is used to It is characterized by estimating SOH.

  According to the configuration (6), since the relationship between the internal temperature of the battery, the internal resistance, and the SOH has a preset SOH map and can be used to estimate the SOH of the battery, the SOH can be quickly and accurately estimated. Can be estimated.

  According to at least one embodiment of the present invention, the battery temperature used for battery state estimation can be accurately estimated, and the healthy state of the battery can be accurately estimated using the estimated temperature.

1 is an overall configuration diagram of a battery temperature estimation device and a battery state estimation device according to an embodiment of the present invention. It is explanatory drawing of the temperature equivalent circuit model of the battery temperature estimation apparatus which concerns on one Embodiment of this invention, (A) shows a physical model, (B) shows the simplified model, (C) is an equivalent circuit model Indicates. It is explanatory drawing of the temperature equivalent circuit model of the battery temperature estimation apparatus which concerns on one Embodiment of this invention, (A) shows a physical model, (B) shows the simplified model, (C) is an equivalent circuit model Indicates. It is an estimation flowchart which shows the battery temperature estimation method which concerns on one Embodiment of this invention. It is an estimation flowchart which shows the estimation method of SOH in the battery state estimation apparatus which concerns on one Embodiment of this invention. An example of the SOH map for calculating SOH in the battery state estimation apparatus which concerns on one Embodiment of this invention is shown. The battery equivalent circuit model in the SOC and internal resistance estimation part of the battery temperature estimation apparatus which concerns on one Embodiment of this invention is shown.

  Several embodiments of the present invention will be described below with reference to the accompanying drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in these embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples. Only.

A battery temperature estimation device 1 and a battery state estimation device 3 according to an embodiment of the present invention will be described with reference to the overall configuration diagram of FIG.
The battery 5 is a driving battery in an electric vehicle such as an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. As shown in FIG. 1, the battery 5 is configured as an aggregate of a plurality of battery cells 5a. .

  As shown in FIG. 1, the battery temperature estimation device 1 mainly includes an in-pack temperature sensor (in-pack temperature detection unit) 9 that detects an environmental temperature inside the battery pack 7 in which the battery 5 is housed. A battery temperature sensor (battery temperature detection unit) 11 that is installed in the battery 5 and detects an outer surface temperature of the battery 5; a current sensor (current detection unit) 13 that detects a charge / discharge current of the battery 5; A voltage sensor 15 that detects a voltage; an SOC / internal resistance estimation unit 17 that estimates an SOC of the battery 5 and an internal DC resistance of the battery 5; and a battery temperature estimation unit 19 that estimates an internal temperature of the battery 5. Yes.

  The battery temperature estimation unit 19 includes an internal environmental temperature of the battery pack 7 detected by the in-pack temperature sensor 9, an outer surface temperature of the battery 5 detected by the battery temperature sensor 11, a current detected by the current sensor 13, and the SOC. The internal temperature of the battery 5 is estimated based on the internal DC resistance estimated by the internal resistance estimation unit 17.

The battery temperature sensor 11 is provided for each of the plurality of battery cells 5a and detects the temperature of each cell. Further, the voltage shown in FIG. 1 is also detected for each battery cell 5a. Further, the battery temperature estimation unit 19 that estimates the internal temperature of the battery 5 also estimates the internal temperature for each cell.
When the battery temperature sensor 11 is not installed in each cell and only a number smaller than the number of cells is installed in the module, the temperature distribution of the battery temperature sensor 11 and each cell is acquired in advance and stored as a table.

  The battery temperature estimation unit 19 includes a temperature equivalent circuit model (air-cooling temperature equivalent circuit model) 21 and a Kalman filter 23, and estimates the internal temperature of the battery cell 5 a by the Kalman filter 23 using the temperature equivalent circuit model 21. .

  Generally, the Kalman filter 23 is one of system identification methods for estimating a state quantity that cannot actually be observed. The Kalman filter uses an equivalent circuit model of the system under consideration. The equivalent circuit model is used to estimate the observable physical quantity. The equivalent circuit model is used to estimate the state variable or parameter at the current time from the state variable or parameter at the previous time. From the difference, the parameters and state variables used in the equivalent circuit model are corrected (gain is applied), and the unobservable state quantity is estimated.

With reference to FIG. 2, the estimation of the internal temperature of the battery 5 (battery cell 5a) by the battery temperature estimation unit 19 in the embodiment of temperature adjustment by air cooling will be described.
2A shows a battery cell 5a with a temperature regulator that adjusts the temperature of the battery cell 5a through the ambient temperature in the battery pack 7 including air cooling, here, not only cooling but also heating, This is a physical model in which the in-pack temperature sensor 9 and the battery temperature sensor 11 are modeled.

The internal temperature of the battery cell 5a to be known here is T1, the temperature of the battery temperature sensor 11 installed in the battery cell 5a is T2, and the temperature of the in-pack temperature sensor 9 installed in the battery pack 7 is Ta. To do.
Further, the current of the battery cell 5a (value of the current sensor 13) is I, and the internal resistance of the battery cell 5a (internal resistance value estimated by the SOC / internal resistance estimating unit 17) is _R0 .

FIG. 2B is a simplified model of FIG. As described above, T1, T2, and Ta are the temperature of the in-pack temperature sensor 9 is Ta, the temperature of the battery temperature sensor 11 is T2, and the estimated internal temperature of the battery cell 5a is T1.
R2a is a thermal resistance between the temperature Ta of the in-pack temperature sensor 9 and the temperature T2 of the battery temperature sensor 11, and R12 is the temperature T2 of the battery temperature sensor 11 and the battery cell 5a to be estimated. It is a thermal resistance between internal temperature T1. Further, the heat capacity at the temperature T2 portion is C2, and the heat capacity at the internal temperature T1 portion is C1.

  FIG. 2C is a temperature equivalent circuit model 21 created based on the simplified model of FIG. It is created by replacing thermal resistance and thermal capacity as equivalent to the electrical resistance and capacitance (capacitor) of the electric circuit and replacing temperature as equivalent to the voltage.

ここで、Ｑｉｎ＝Ｉ²Ｒ_０は、バッテリセル５ａの内部での発熱量である。 The following equations (1) and (2) are obtained by formulating the temperature equivalent circuit model 21.
Equation (1) shows the balance of the amount of heat (corresponding to the current value in the electric circuit) at the intersection P1 of the temperature equivalent circuit model 21 of FIG. 2 (C). Equation (2) is shown in FIG. The balance of the amount of heat at the intersection P2 of the temperature equivalent circuit model 21 of (C) is shown in the equation.

Here, Qin = I ² R ₀ is the amount of heat generated inside the battery cell 5a.

ここで、上添字のＫ−１、Ｋはそれぞれ時系列データのＫ−１番目、Ｋ番目の値を表す。Ｋ−１の値でＫの値を表している。 When equations (1) and (2) are rewritten into state equations expressing time evolution, the following equations (3) and (4) are obtained.

Here, the superscripts K-1 and K represent the K-1th and Kth values of the time series data, respectively. The value of K represents the value of K.

とする。状態方程式を

の形に書くと、ｆ（ｘ_Ｋ−１）は、

となる。 To consider the state equation,

And Equation of state

F (x _K-1 ) is

It becomes.

とする。観測方程式は

である。 The observation vector is

And The observation equation is

It is.

である。対角以外の要素は全てゼロである。 An example of system noise covariance is

It is. All elements other than diagonal are zero.

である。ここでＲＴ２、ＲＴａは、Ｔ２、Ｔａのノイズ共分散である。 Observation noise covariance is

It is. Here, RT2 and RTa are noise covariances of T2 and Ta.

  From the equation (7) of the state equation and the equation (9) of the observation equation, the state variable T1, that is, the internal temperature of the battery cell 5a, is estimated using the Kalman filter method that is a system identification method.

Next, the procedure for estimating the internal temperature of the battery cell 5a by the battery temperature estimating unit 19 will be described with reference to the flowchart of FIG.
First, in step S1, data on the internal temperature of the battery pack 7 detected by the in-pack temperature sensor 9 is obtained. In step S2, data on the outer surface temperature of the battery cell 5a detected by the battery temperature sensor 11 is obtained. In step S3, the charge / discharge current data of the battery cell 5a detected by the current sensor 13 is obtained.

Thereafter, in step S4, the SOC / internal resistance estimating unit 17 estimates the SOC of the battery cell 5a and the DC resistance of the battery cell 5a.
In step S5, a temperature equivalent circuit model 21 shown in FIGS. 2A to 2C is created. In step S6, the analysis method of the Kalman filter 23 is applied based on the temperature equivalent circuit model 21, and the internal temperature T1 of the battery cell 5a is estimated.

Next, the SOC / internal resistance estimation unit 17 will be described.
The estimation of the SOC of the battery cell 5a in the SOC / internal resistance estimation unit 17 and the estimation of the internal resistance of the battery cell 5a are estimated by the same method as that estimated using the Kalman filter 23 in the battery temperature estimation unit 19 described above. .

In the SOC / internal resistance estimation unit 17, an example of a state vector is represented by Equation (12) based on the battery equivalent circuit model 29 of FIG. 7, and an example of the state equation is represented by Equation (13). It becomes like this.
The battery equivalent circuit model 29 shown in FIG. 7 includes an OCV (open circuit voltage) that is an electromotive force and a parasitic component. The regulating component is composed of a direct resistance component and a CR circuit that expresses a diffusion phenomenon inside the battery. In FIG. 7, the CR circuit indicates three series.

Furthermore, an example of the observation vector is as shown in Expression (14), and an example of the observation equation is as shown in Expression (15).

From the state equation (13) and the state equation (15), the SOC / internal resistance estimator 17 estimates the SOC of the state variable and the parameter R ₀ using the Kalman filter technique.

Next, the SOH estimation unit 31 will be described.
The SOH estimating unit 31 estimates SOH based on the internal temperature T1 of the battery cell 5a estimated by the battery temperature estimating unit 19 and the internal resistance _R0 estimated by the SOC / internal resistance estimating unit 17.

For the estimation of the SOH, as shown in FIG. 6, the relationship between the internal temperature T1, the internal resistance _R0, and the SOH of the battery cell 5a is estimated using a preset SOH map 33.
In FIG. 6, for example, when the temperature is 40 ° C. and the internal resistance is R ₀₄ , it is estimated that the SOH is X%. In the case of an intermediate value between set values, it is estimated by complementing (proportional distribution) based on the set value.

Next, the procedure for estimating the SOH of the battery cell 5a by the SOH estimating unit 31 will be described with reference to the flowchart of FIG.
First, in step S11, an estimated value of the internal temperature of the battery cell 5a by the battery temperature estimation unit 19 is read. In the next step S12, the estimated value of the DC resistance of the internal resistance of the battery cell 5a by the SOC / internal resistance estimation unit 17 is read. Thereafter, in step S13, the soundness level is obtained by referring to the SOH map 33 based on the internal temperature of the battery cell 5a estimated in step S11 and the internal resistance of the battery cell 5a estimated in step S12.

  According to the present embodiment described above, the internal temperature of the battery pack 7 detected by the in-pack temperature sensor 9, the external surface temperature of the battery cell 5a detected by the battery temperature sensor 11, the current detected by the current sensor 13, the SOC · Since the battery cell estimation unit 19 that estimates the internal temperature of the battery cell 5a by the Kalman filter 23 using the temperature equivalent circuit model 21 based on the internal resistance of the battery cell 5a estimated by the internal resistance estimation unit 17 is provided. The internal temperature of 5a can be accurately estimated. Thereby, the estimation accuracy of the health degree (SOH) of the battery module in which the battery cell 5a and the battery cell 5a are assembled can be improved.

  Further, a temperature equivalent circuit model 21 corresponding to an equivalent circuit model of the electric circuit is created, a state equation (7) and an observation equation (9) are created, and the Kalman filter 23 is created from the state equation (7) and the observation equation (9). The estimation method can be applied, and the internal temperature of the battery cell 5a can be estimated.

  Further, since the temperature equivalent circuit model 21 in which the battery pack 7 is cooled by air cooling is used, it is possible to accurately estimate the battery state of the system in which the battery pack 7 is cooled by air cooling.

  Furthermore, according to this embodiment, since the battery temperature estimation unit 19 that estimates the internal temperature of the battery cell 5a using the Kalman filter 23 is provided, the temperature sensor installed on the outer surface of the conventional battery cell or in the vicinity of the outer surface is used. Since the battery cell temperature can be obtained with higher accuracy than the temperature information, the estimation accuracy of the soundness (SOH) of the battery cell 5a can be improved.

Next, another embodiment will be described with reference to FIGS.
3 is characterized by water cooling (cooling through a water jacket), whereas the embodiment of FIG. 2 is air cooling (cooling by the ambient temperature in the battery pack 7). . As shown in FIGS. 1 and 3, a water temperature sensor 37 for detecting the water temperature in the water jacket 35 installed in the battery cell 5a is installed.

  FIG. 3 (A) shows a battery cell 5a with a temperature regulator that adjusts the temperature of the battery cell 5a through a water jacket 35, including not only cooling but also heating (heater), and a pack. This is a physical model in which the internal temperature sensor 9 and the battery temperature sensor 11 are modeled.

The pack that is installed inside the battery pack 7 and detects the ambient temperature of the battery cell 5a, where T1 is the internal temperature of the battery cell 5a to be known and T2 is the temperature of the battery temperature sensor 11 installed in the battery cell 5a. The temperature of the internal temperature sensor 9 is Ta.
Further, the current of the battery cell 5a (the value of the current sensor 13) is I, and the internal resistance of the battery cell 5a (the internal resistance estimated by the SOC / internal resistance estimating unit 17) is _R0 . Is Tw.

  FIG. 3B is a simplified model of FIG. As described above, T1, T2, Ta, and Tw indicate that the temperature of the in-pack temperature sensor 9 is Ta, the temperature of the battery temperature sensor 11 is T2, the internal temperature of the battery cell 5a to be estimated is T1, the water temperature sensor 37 The temperature is Tw.

  R2a is a thermal resistance between the temperature Ta of the in-pack temperature sensor 9 and the temperature T2 of the battery temperature sensor 11, and R12 is the inside of the battery cell 5a to be estimated as the temperature T2 of the battery temperature sensor 11. R1w is a thermal resistance between the internal temperature T1 of the battery cell 5a and the temperature Tw of the water temperature sensor 37. Further, the heat capacity at the temperature T2 portion is C2, and the heat capacity at the internal temperature T1 portion is C1.

  FIG. 3C shows a temperature equivalent circuit model (water cooling temperature equivalent circuit model) 39 created based on the simplified model of FIG. It is created by replacing thermal resistance and thermal capacity as equivalent to the electrical resistance and capacitance (capacitor) of the electric circuit and replacing temperature as equivalent to the voltage.

ここで、Ｑｉｎ＝Ｉ²Ｒ_０は、バッテリセル５ａの内部での発熱量である。 Expressions (21) and (22) below are mathematical expressions of the temperature equivalent circuit model 39.
Equation (21) shows the balance of current values at the intersection point P1 of the temperature equivalent circuit model of FIG. 3C, and Equation (22) shows the temperature equivalent circuit model of FIG. The balance of the amount of heat (corresponding to the current value in the electric circuit) at the intersection P2 is shown in the equation.

Here, Qin = I ² R ₀ is the amount of heat generated inside the battery cell 5a.

ここで、上添字のＫ−１、Ｋはそれぞれ時系列データのＫ−１番目、Ｋ番目の値を表す。Ｋ−１の値でＫの値を表している。 When the equations (21) and (22) are rewritten into a state equation expressing the time evolution, the following equations (23) and (24) are obtained.

Here, the superscripts K-1 and K represent the K-1th and Kth values of the time series data, respectively. The value of K represents the value of K.

とする。状態方程式を

の形に書くと、ｆ（ｘ_Ｋ−１）は、

となる。 To consider the state equation,

And Equation of state

F (x _K-1 ) is

It becomes.

とする。観測方程式は

である。 The observation vector is

And The observation equation is

It is.

である。対角以外の要素は全てゼロである。 An example of system noise covariance is

It is. All elements other than diagonal are zero.

である。ここでＲＴ２、ＲＴａ、Ｒｔｗは、Ｔ２、Ｔａ、Ｔｗのノイズ共分散である。 Observation noise covariance is

It is. Here, RT2, RTa, and Rtw are noise covariances of T2, Ta, and Tw.

  From the equation (27) of the state equation and the equation (29) of the observation equation, T1 of the state variable, that is, the temperature in the battery cell 5a, is estimated using the Kalman filter method that is a system identification method.

  According to another embodiment shown in FIGS. 1 and 3 described above, in addition to the operation and effect of the embodiment already described, the battery pack 7 is a temperature equivalent circuit model 39 cooled by water cooling. The battery state of the system in which the inside of the pack 7 is cooled by water cooling can be accurately estimated.

  Since the temperature equivalent circuit model includes the air-cooling temperature equivalent circuit model 21 and the water-cooling temperature equivalent circuit model 39 as in the embodiment of FIG. 2 and the embodiment of FIG. 3, the battery 5 (battery cell 5a The internal temperature of the battery can be estimated using an appropriate temperature equivalent circuit model corresponding to the cooling system. Thereby, the temperature in the battery cell 5a can be estimated further, and the battery state can be estimated more accurately.

  According to at least one embodiment of the present invention, the battery temperature used for battery state estimation can be accurately estimated, and the battery state can be accurately estimated using the estimated temperature. Suitable for use in battery state estimation device.

DESCRIPTION OF SYMBOLS 1 Battery temperature estimation apparatus 3 Battery state estimation apparatus 5 Battery 5a Battery cell 7 Battery pack 9 In-pack temperature sensor (In-pack temperature detection part)
11 Battery temperature sensor (battery temperature detector)
13 Current sensor (current detector)
15 Voltage Sensor 17 SOC / Internal Resistance Estimator (Internal Resistance Estimator)
19 Battery temperature estimation unit 21 Air cooling temperature equivalent circuit model 23 Kalman filter 31 SOH estimation unit 33 SOH map 35 Water jacket 37 Water temperature sensor 39 Water cooling temperature equivalent circuit model

Claims (6)

An in-pack temperature detector that detects the internal temperature of the battery pack in which the battery is housed;
A battery temperature detection unit that is installed in the battery and detects an outer surface temperature of the battery;
A current detector for detecting a charge / discharge current of the battery;
An internal resistance estimator for estimating the internal resistance of the battery;
A temperature equivalent circuit model of the battery having thermal resistance and thermal capacity as parameters;
The internal temperature of the battery pack detected by the in-pack temperature detector, the external surface temperature of the battery detected by the battery temperature detector, the current detected by the current detector, and the interior of the battery estimated by the internal resistance estimator A battery temperature estimation device comprising: a battery temperature estimation unit that estimates an internal temperature of the battery by a Kalman filter using the temperature equivalent circuit model based on a resistance.   The battery temperature estimating unit detects the state variable by the Kalman filter from a state equation and an observation equation having an outer surface temperature of the battery, an internal temperature of the battery pack, and an internal temperature of the battery as state variables. The battery temperature estimation device according to claim 1, wherein the battery temperature estimation device sequentially estimates based on the current.   The temperature equivalent circuit model includes an air cooling temperature equivalent circuit model when the battery is cooled by cold air, and a liquid cooling temperature equivalent circuit model when the battery is cooled in contact with the refrigerant liquid. The battery temperature estimation apparatus according to claim 1 or 2, wherein An in-pack temperature detection step for detecting the internal temperature of the battery pack in which the battery is accommodated;
A battery temperature detecting step for detecting an outer surface temperature of the battery;
A current detection step for detecting a charge / discharge current of the battery;
An internal resistance estimating step for estimating the internal resistance of the battery;
Creating a temperature equivalent circuit model of the battery having thermal resistance and thermal capacity as parameters;
The temperature equivalent circuit based on the internal temperature of the battery pack in the pack temperature detection step, the outer surface temperature of the battery in the battery temperature detection step, the current in the current detection step, and the internal resistance of the battery in the internal resistance estimation step A battery internal temperature estimating step for estimating the internal temperature of the battery by a Kalman filter using a model.   The battery temperature estimation device according to any one of claims 1 to 3, further comprising: an internal temperature of the battery estimated by the battery temperature estimation device and an internal resistance estimated by the internal resistance estimation unit. A battery state estimation apparatus comprising an SOH estimation unit for estimating the SOH of the battery.   The SOH estimation unit includes an SOH map in which a relationship among an internal temperature of the battery, the internal resistance, and the SOH is set in advance, and estimates the SOH using the SOH map. Item 6. The battery state estimation device according to Item 5.

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