Battery performance evaluation device and battery performance evaluation method

Abstract

An apparatus capable of evaluating the performance of a secondary battery while reducing the computational processing load required to determine the values ​​of model parameters that define a model used to evaluate the performance of the secondary battery. Depending on whether a specified condition is satisfied or not, a different battery model is determined as the battery model used to evaluate the performance of the target secondary battery. Specifically, when the specified condition is satisfied, a second battery model is determined, which is a simpler battery model than the first battery model defined by the plurality of first model parameters (the battery model determined when the specified condition is not satisfied), to the extent that it is defined by a second model parameter that is a smaller number than the plurality of first model parameters.

Description

Technology Field

[0001] The present invention relates to a system for determining the degradation state of a secondary battery, such as a lithium-ion battery. Background Technology

[0002] A technical method is proposed by the applicant for determining the degradation state of a secondary battery even when there is no initial measurement result of the characteristic parameters of the secondary battery itself (see Patent Document 1). Specifically, a past value of voltage (V) is specified as an initial characteristic estimate value (V(0←k)) according to a multivariable function (G) representing an initial characteristic model based on the current measurement value of voltage (V) (V(k)) and the current measurement value of current (I(k)) of the secondary battery. The 'initial characteristic model' is a model representing the initial characteristics of a reference secondary battery of the same specifications as the secondary battery subject to degradation state determination.

[0003] A technical method for evaluating the battery performance of a secondary battery is proposed by the applicant using a secondary battery model in which the impedance of the internal resistance of the secondary battery is expressed by an impulse response representing each of an IIR system and an FIR system (see Patent Document 2). Prior art literature

[0004] [Patent Document 1] Patent Publication No. 6745554 [Patent Document 2] Patent Publication No. 6842212 The problem to be solved

[0005] However, if the number of model parameters defining the model is large, the computational processing load required to determine the values ​​of the corresponding model parameters may become excessive. For this reason, there was a possibility that the scope of application would be limited, such as when it became difficult to perform on-board evaluation processing of the battery performance of the secondary battery installed in the device.

[0006] Accordingly, the present invention aims to provide an apparatus, etc., capable of evaluating the performance of a secondary battery while reducing the computational processing load required to determine the values ​​of model parameters that define a model used to evaluate the performance of the secondary battery. means of solving the problem

[0007] The battery performance evaluation device according to the present invention is,

[0008] A first recognition processing element that recognizes the measurement result of the impedance of a reference secondary battery, and

[0009] A first computational processing element that, based on the measurement result of the impedance of the reference secondary battery recognized by the first recognition processing element, determines a first battery model defined by the plurality of first model parameters by identifying the values ​​of each of the plurality of first model parameters when the designated condition is not satisfied, and determines a second battery model defined by the plurality of second model parameters by identifying the values ​​of each of the plurality of second model parameters that are a minority of the plurality of first model parameters when the designated condition is satisfied;

[0010] A second recognition processing element that recognizes the actual output voltage as a measurement result of the change pattern of the voltage output from the target secondary battery when a designated current is input to a target secondary battery having the same specifications as the above-mentioned reference secondary battery, and

[0011] For the first battery model or the second battery model determined by the first computational processing element, a second computational processing element that specifies a model output voltage as a change pattern of voltage output from the first battery model or the second battery model when the specified current is input, and

[0012] The battery performance evaluation element is provided to evaluate the performance of the target secondary battery based on the comparison result between the actual output voltage recognized by the second recognition processing element and the model output voltage specified by the second computation processing element.

[0013] According to the battery performance evaluation device of the present invention, depending on whether a specified condition is satisfied or not, a different battery model is determined as a battery model used for evaluating the performance of a target secondary battery. Specifically, when the specified condition is satisfied, a second battery model is determined, which is a simpler battery model than the first battery model defined by the plurality of first model parameters (the battery model determined when the specified condition is not satisfied), as it is defined by a plurality of second model parameters that are fewer than the plurality of first model parameters. Therefore, compared to the case where the first battery model is established regardless of whether the specified condition is satisfied, the computational processing load required for identifying the model parameters of the battery model used for evaluating the performance of the target secondary battery is reduced. Effects of the invention

[0014] According to the battery performance evaluation device (100) and the battery performance evaluation method executed by the present invention, depending on whether a specified condition is satisfied or not, another battery model is determined as a battery model used for evaluating the performance of a target secondary battery. Specifically, when the specified condition is satisfied, a second battery model is determined from a first battery model defined by a plurality of first model parameters (a battery model determined when the specified condition is not satisfied), which is a simplified battery model defined by a second model parameter that is fewer than that of the first battery model (see FIG. 2 / STEP 114 ‥YES→STEP 118). Therefore, compared to the case where the first battery model is established regardless of whether the specified condition is satisfied, the computational processing load required for the identification of model parameters of the battery model used for evaluating the performance of the target secondary battery (220) is reduced. Brief explanation of the drawing

[0015] FIG. 1 is an explanatory diagram regarding the configuration of a battery performance evaluation device as an embodiment of the present invention. Figure 2 is a flowchart showing the procedure of the battery performance evaluation method of a target secondary battery. Figure 3a is an explanatory diagram regarding the first battery model (full model). Figure 3b is an explanatory diagram regarding the second battery model (simplified model). Figure 4a is an explanatory diagram of the Nyquist plot based on the full model of a secondary battery. Figure 4b is an explanatory diagram of the Nyquist plot based on a simplified model of a secondary battery. Figure 5a is an explanatory diagram regarding the designated current. FIG. 5b is an explanatory diagram regarding the voltage response characteristics of a secondary battery and a battery model. Specific details for implementing the invention

[0016] (Configuration of battery performance evaluation device)

[0017] A battery performance evaluation device (100) as an embodiment of the present invention illustrated in FIG. 1 is configured by one or more servers capable of communicating with each of the database (10) and the target device (200) through a network. The battery performance evaluation device (100) evaluates the performance of a secondary battery (220) installed as a power source in the target device (200).

[0018] The battery performance evaluation device (100) is equipped with a first recognition processing element (111), a second recognition processing element (112), a first computation processing element (121), a second computation processing element (122), a battery performance evaluation element (130), and an information providing element (132). Each of the first recognition processing element (111), the second recognition processing element (112), the first computation processing element (121), the second computation processing element (122), the battery performance evaluation element (130), and the information providing element (132) is composed of a processor (computation processing device), a memory (storage device), and an I / O circuit, etc. In the memory or a storage device separate from it, a program (software) is stored and retained in addition to various data, such as measurement results of the voltage response characteristics of the secondary battery (220) for a designated current. For example, each of a plurality of identifiers for identifying the type (specified by specifications and standards) of a secondary battery (220) or a target device (200) equipped with it, and each of a plurality of secondary battery models are stored in memory in correspondence.

[0019] The processor reads the necessary programs and data from memory and executes computational processing according to the program based on the data, thereby executing the computational processing or tasks described below assigned to each element (111, 112, 121, 122, 130 and 132). The statement that each element ‘recognizes’ information means that it executes all computational processing that prepares information or data required for subsequent computational processing, such as receiving information, searching for or reading information from an information source such as a database (10), and calculating, estimating, identifying, or predicting information by executing computational processing on basic information.

[0020] The target device (200) is equipped with an input interface (202), an output interface (204), a control device (210), a secondary battery (220), and a sensor group (230). The target device (200) includes all devices that use the secondary battery (220) as a power source, such as a PC, a mobile phone (smartphone), a home appliance, or a moving object such as an electric bicycle.

[0021] The control device (210) is composed of a processor (computation processing unit), memory (storage device), and I / O circuits, etc. Various data, such as measurement results of the voltage response characteristics of the secondary battery (220), are stored and retained in the said memory or a storage device separate from it. The control device (210) operates according to the power supplied from the secondary battery (220) and controls the operation of the target device (200) in a powered state. The operation of the target device (200) includes the operation of an actuator (electric actuator, etc.) that constitutes the target device (200). The processor constituting the control device (210) reads the necessary program and data from the memory and executes the computational processing assigned according to the program based on the said data.

[0022] The secondary battery (220) is, for example, a lithium-ion battery, and may be any other secondary battery such as a nickel-cadmium battery. The sensor group (230) measures the values ​​of parameters required for controlling the target device (200), in addition to the voltage response characteristics and temperature of the secondary battery (220). The sensor group (230) is composed of, for example, a voltage sensor, a current sensor, and a temperature sensor that output signals according to the voltage, current, and temperature of the secondary battery (220), respectively.

[0023] The battery performance evaluation device (100) may be mounted on the target device (200). In this case, a software server (not shown) may transmit software for determining degradation to a computational processing unit constituting a control device (210) equipped in the target device (200), thereby granting the corresponding computational processing unit the function of a battery performance evaluation device (100).

[0024] (Battery performance evaluation method)

[0025] A method for evaluating the battery performance of a secondary battery (220) (target secondary battery) executed by the battery performance evaluation device (100) of the above configuration is described below.

[0026] (Recognition of impedance measurement results)

[0027] By the first recognition processing element (111) in the battery performance evaluation device (100), the measurement result of the impedance, such as the complex impedance (Z) of the secondary battery (220) as a reference secondary battery of various types, is recognized (Fig. 2 / STEP 112). The complex impedance (Z) of the reference secondary battery is measured by the AC impedance method, and the measurement result is registered in the database (10) in relation to an identifier for identifying the type of reference secondary battery.

[0028] The complex impedance (Z) of the secondary battery (220) as a reference secondary battery when it is not mounted on the target device (200) is measured. Alternatively, the complex impedance (Z) of the secondary battery (220) as a reference secondary battery when it is mounted on the target device (200) may also be measured. For example, the target device (200) may be connected to a power source, such as a commercial power source, to charge the secondary battery (220), and a sinusoidal signal may be output by the power supplied from the said power source.

[0029] FIG. 4a shows an example of a Nyquist plot representing the actual measurement result of the complex impedance (Z) of a secondary battery (220), along with an approximate curve of the plot. The horizontal axis represents the real part (ReZ) of the complex impedance (Z), and the vertical axis represents the imaginary part (-ImZ) of the complex impedance (Z). In the region where -ImZ > 0, as ReZ increases, a low-frequency complex impedance (Z) appears. The value of ReZ at -ImZ = 0 corresponds to the resistance of movement in the electrolyte of the secondary battery (220). The radius of curvature of the approximately semicircular portion in the region where -ImZ > 0 corresponds to the resistance of charge movement of the secondary battery (220). The radius of curvature tends to decrease as the temperature (T) of the secondary battery (220) becomes high. In the low frequency region of the -ImZ > 0 region, the linear portion rising at approximately 45° reflects the influence of the Warburg impedance of the secondary battery (220).

[0030] (Establishment of a secondary battery model)

[0031] In the battery performance evaluation device (100), whether a designated condition is satisfied is determined by the first computational processing element (121) (Fig. 2 / STEP 114). The designated condition is, for example, a condition that the designated current applied to the secondary battery (220) as the target secondary battery is composed of a low-frequency current component lower than the sampling frequency. For example, in the Nyquist plot shown in Fig. 4a, a frequency (~1 Hz) corresponding to the straight-line rising part of about 45° in the low-frequency region of the -ImZ > 0 region may be adopted as the sampling frequency. For example, the current composed of a low-frequency current component corresponding to the charge / discharge current of the secondary battery (220) corresponds to the designated current.

[0032] In addition to this condition, or instead of this condition, a condition that the computational processing load (CPU usage rate, etc.) of the first computational processing element (121) is greater than or equal to a reference value, a condition that the target device (200) is a device with a request precision or urgency level for performance evaluation of the secondary battery (220) that is less than or equal to a threshold value (e.g., a device with a low degree of functional degradation due to performance degradation of the secondary battery (220), such as a smartphone, personal computer, etc.), and / or a condition that the elapsed time since the last performance evaluation of the secondary battery (220) that is the subject of this performance evaluation is less than a specified period may be defined as a specified condition.

[0033] If it is determined that the specified condition is not satisfied (Fig. 2 / STEP 114...NO), the values ​​of each of the plurality of first model parameters defining the first battery model are identified at different temperatures based on the measurement result of the complex impedance (Z) of the secondary battery (220) as a reference secondary battery recognized by the first recognition processing element (111) (Fig. 2 / STEP 116).

[0034] The first battery model is a model representing the voltage (V(z)) output from the secondary battery (220) when a current (I(z)) is input to the secondary battery (220). The first battery model (full model) includes, for example, a resistance (r0) corresponding to the resistance of movement in the electrolyte, a Warburg impedance (W), and a resistance (r) corresponding to the resistance of charge movement, as shown in FIG. 3a. i ) and capacitor(C i The i-th RC parallel circuit (i=1, 2, ‥, m) composed of ), and a coil (L) and a resistor (r L An LR parallel circuit consisting of ) is defined by an equivalent circuit connected in series.

[0035] The number of RC parallel circuits connected in series may be less than 3 or more than 3. The Warburg impedance (W) may be connected in series with the resistor (R) in at least one RC parallel circuit. The capacitor (C) may be replaced with a CPE (Constant Phase Element).

[0036] The first battery model is defined by the relationship (11) using the open-circuit voltage (OCV(z)) and the transfer function (H1(z)) of the internal resistance of the secondary battery (220).

[0037] V(z)=OCV(z)+H1(z)·I(z) ‥(11).

[0038] Here, OCV(z) indicates that the open-circuit voltage increases or decreases in conjunction with the charging and / or discharging of the current (I(z)).

[0039] The transfer function (H1(z)) of the internal resistance in the first battery model is the transfer function (H0(z)) of the resistance (r0) defined by the relationship (12), and the transfer function (H) of the i-th RC parallel circuit defined by the relationship (13). i (z)), the transfer function (H) of the Warburg impedance (W) defined by the relationship (14) W(z)), and the transfer function (H) of the LR parallel circuit defined by the relationship (15) L It is defined by the relationship (16) using (z)).

[0040] H0(z)=r0‥(12).

[0041] H i (z)=(b i0 +b i1 z -1 ) / (1+a i1 z -1 ) ‥(13).

[0042] Here, a i , b i0 and b i1 It is represented by coefficient relationships (131) and (132) using the sampling period (T).

[0043] a i =-( T-2r i C i ) / (T+r i C i ) ‥(131).

[0044] b i0 =b i1 =r i T / (T+r i C i ) ‥(132).

[0045] Transfer function (h) of Warburg impedance (W) suitable for experimental data W (s)) is represented in the frequency domain by the relationship (141) or (142).

[0046] h W (s)=w1·tanh{(sw2) w3} / (sw2) w3 ‥(141).

[0047] h W (s)=w1·coth{(sw2) w3} / (sw2) w3 ‥(142).

[0048] The corresponding transfer function is expanded to the FIR to correspond to the impulse response and is expressed by equations (14) to (16).

[0049] H W (z)=Σ n k=0 h k z -k ‥(14).

[0050] H L (z)=(2L0 / T)(1-z -1 ) / (1+z -1 ) ‥(15).

[0051] H1(z)=H L (z)+Σ m i=1 H i (z)+H W (z)+H0(z) ‥(16).

[0052] The approximate curve of the complex impedance (Z) of the secondary battery, represented by the Nyquist plot shown as a solid line in FIG. 4a, is obtained under the assumption that the transfer function (H(z)) of the equivalent circuit model of the internal resistance of the secondary battery is defined according to the relationship (16). Accordingly, the first model parameters (r0, r i , C i , w1, w2, w3, r L The values ​​of and L) are obtained (see relational expressions (12) to (15)). Table 1 shows the results of identifying the values ​​of the first model parameters and an example of the time constant.

[0053] parameters value City constant r0 0.0103Ω r1 0.00207Ω 5.71ms C1 2.76F r2 0.00241Ω 0.718ms C2 0.298F r3 0.00172Ω 0.0687ms C3 0.0687F W R 0.0516Ω W T 164.4 W P 0.6065 L1 0.515μH ≤1ms r L 1.19Ω

[0054] The value of the open-circuit voltage (OCV) in the secondary battery model is determined by the measured value of the open-circuit voltage (OCV) (see relational equation (11)). Then, the first battery model is established as a secondary battery (220) as a reference secondary battery of various specifications or standards by the value of the corresponding parameter. On the other hand, if it is determined that the specified condition is satisfied (Fig. 2 / STEP 114 . YES), the value of each of the multiple second model parameters defining the second battery model is determined at different temperatures based on the measurement result of the complex impedance (Z) of the secondary battery (220) as a reference secondary battery recognized by the first recognition processing element (111) (Fig. 2 / STEP 118). The second battery model is a model that represents the voltage (V(z)) output from the secondary battery (220) when a current (I(z)) is input to the secondary battery (220), just like the first battery model. The second battery model is the transfer function (H) of the i-th RC parallel circuit defined by the relationship (13). i (z)) is a simplified model compared to the first cell model when the time constant is sufficiently smaller than the sampling period (T). For example, the second cell model is defined by an equivalent circuit in which a single resistor (R0) and a Warburg impedance (W) are connected in series, as shown in FIG. 3b.

[0055] The second battery model is defined by the relationship (21) using the open-circuit voltage (OCV(z)) and the transfer function (H2(z)) of the internal resistance of the secondary battery (220).

[0056] V(z)=OCV(z)+H2(z)·I(z) ‥(21).

[0057] The transfer function of internal resistance (H1(z)) in the second battery model is the transfer function of resistance (R0) (H0(z)) defined by equation (22) and the transfer function of Warburg impedance (W) (H) defined by equation (14). W(z)) is defined by the relationship (26). Resistance (R0) is defined by resistance (r0) corresponding to the resistance of movement in the electrolyte and resistance (r) corresponding to the resistance of charge movement. i )(i=1, 2, ‥, m) is considered as a single resistance as a result of concentration.

[0058] H0(z)=R0=r0+Σ m i=1 r i ‥(22).

[0059] H2(z)=H W (z)+H0(z) ‥(26).

[0060] The approximate curve of the complex impedance (Z) of the secondary battery (particularly the linear portion in the region where -ImZ > 0) represented by the Nyquist plot shown as a solid line in FIG. 4b is obtained under the assumption that the transfer function (H(z)) of the equivalent circuit model of the internal resistance of the secondary battery is defined according to the relationship (26). Accordingly, the second model parameters (r0, r i The values ​​of w1, w2 and w3) are obtained (see equations (22) and (14). The value of the open-circuit voltage (OCV) in the secondary battery model is identified by the measured value of the open-circuit voltage (OCV) (see equation (21)). Then, the secondary battery model is established as a secondary battery (220) as a reference secondary battery of various specifications or standards by the value of the corresponding parameter.

[0061] The number of second model parameters (R0, w1, w2, w3) is '4', and the first model parameters (r0, r i (i=1~3), C i (i=1~3) w1, w2, w3, r L The number of (, L) is less than '12'. Also, the parameters (w1, w2, w3) that are part of the second model parameters and define the Warburg impedance (W) are common to the parameters (w1, w2, w3) that are part of the first model parameters and define the Warburg impedance (W) in the same way.

[0062] (Secondary Battery Performance Evaluation)

[0063] In the target device (200), whether a first condition is satisfied is determined by a control device (210) in an energized state (Fig. 2 / STEP 212). As the 'first condition,' conditions such as a request for battery performance evaluation of a secondary battery (220) being made through an input interface (202) from the target device (200), or the target device (200) being connected to an external power source for charging the secondary battery (220), are adopted. Based on communication with the target device (200) at an appropriate timing, an identifier ID is recognized by the battery performance evaluation device (100) to identify the specifications and / or standards of the secondary battery (220) as the target secondary battery.

[0064] If it is determined that the first condition is not satisfied (Fig. 2 / STEP 212...NO), the process for determining the satisfaction of the first condition is executed again (Fig. 2 / STEP 212). The process for determining the satisfaction of the first condition (Fig. 2 / STEP 212) may be omitted.

[0065] When it is determined that the first condition is satisfied (Fig. 2 / STEP 212 ……YES), a time-varying designated current (I(t)) as shown in Fig. 5a is input to the secondary battery (220) as the target secondary battery (Fig. 2 / STEP 214). The waveform signal of the designated current (I(t)) may be designated by the second recognition processing element (112) through mutual communication between the battery performance evaluation device (100) and the target device (200). For example, the pulse current generator mounted on the target device (200) is driven by power supplied from an external power source to which the target device (200) is connected, and the designated current (I(t)) generated by the pulse current generator is input to the secondary battery (220). An auxiliary power source for generating the designated current may be mounted on the target device (200).

[0066] Based on the output signal of the sensor group (230), the voltage response characteristic (V(t)) and temperature (T) of the secondary battery (220) are measured by the control device (210) (Fig. 2 / STEP 216). Accordingly, the voltage response characteristic (V(t)) of the secondary battery (220), which changes as shown by the solid line in Fig. 5b, is measured.

[0067] Next, whether the second condition is satisfied is determined by the control device (210) (Fig. 2 / STEP 218). As the 'second condition', conditions such as having acquired a sufficient waveform signal to specify the voltage response characteristic (V(t)), reaching a second time point after a predetermined time has elapsed from the first time point where the first condition was finally determined to be satisfied, and having received a request for battery performance evaluation of the secondary battery (220) through the input interface (202) from the target device (200) are adopted.

[0068] If it is determined that the second condition is not satisfied (Fig. 2 / STEP 218 ‥NO), the process for determining the satisfaction of the first condition is executed again (Fig. 2 / STEP 212). The process for determining the satisfaction of the second condition (Fig. 2 / STEP 218) may be omitted.

[0069] When it is determined that the second condition is satisfied (Fig. 2 / STEP 218 ……YES), the measurement results of the voltage response characteristic (V(t)) and temperature (T) of the secondary battery (220) are transmitted from the target device (200) to the battery performance evaluation device (100) by a transmitting device constituting the output interface (204) (Fig. 2 / STEP 220). In addition, when the voltage response characteristic (V(t)) is measured, measurement condition information for specifying the designated current (I(t)) input to the secondary battery (220) may be transmitted from the target device (200) to the battery performance evaluation device (100).

[0070] In the battery performance evaluation device (100), the measurement results of the voltage response characteristics (V(t)) and temperature (T) of the secondary battery (220) are recognized as the second measurement results by the second recognition processing element (112) (Fig. 2 / STEP 122).

[0071] By the second operation processing element (122), among the multiple secondary battery models registered in the database (10), a first battery model or a second battery model is selected that is associated with each of the identifier ID associated with the second measurement result and the measurement result of the temperature (T) included in the second measurement result (Fig. 2 / STEP 124). If there is no first battery model to evaluate the performance of the secondary battery (220) as the target secondary battery, or if there is a second battery model, the second battery model may be selected. If both the first battery model and the second battery model exist, either battery model (e.g., the first battery model with slightly better performance evaluation precision) may be selected preferentially.

[0072] Furthermore, a designated current (I(t)) is input to the selected first battery model or second battery model by the second computational processing element (122) (Fig. 2 / STEP 126). The designated current (I(t)) may be recognized based on a waveform signal designated by the second recognition processing element (112), or it may be recognized based on measurement condition information transmitted from the target device (200) to the battery performance evaluation device (100).

[0073] A voltage response characteristic (V) output from the first battery model or the second battery model by the second computational processing element (122) model (t)) is specified as the output signal of the corresponding first battery model or the corresponding second battery model (Fig. 2 / STEP 128). Accordingly, the voltage response characteristic (V) of the second battery model, which changes as shown by the dashed line in Fig. 5b, for example, model (t)) is specified as the output signal of the secondary battery model.

[0074] Next, by the battery performance evaluation factor (130), the voltage response characteristic (V(t)) of the secondary battery (220) as the target secondary battery and the voltage response characteristic (V) of the first battery model or the second battery model model Based on the comparison result of (t)), the performance of the corresponding secondary battery (220) is evaluated (Fig. 2 / STEP 130). For example, the voltage response characteristic (V(t)) of the secondary battery (220) as the target secondary battery and the voltage response characteristic (V) of the secondary battery model model (t)) The similarity (x) of the curve representing each is determined. Then, the degradation (D(i)=f(x)) of the secondary battery (220) is determined according to a reduction function (f) with the similarity (x) as the main variable ('i' is an index representing the type of secondary battery (220)). That is, the higher the corresponding similarity (x), the lower the degradation (D) is evaluated, and conversely, the lower the corresponding similarity (x), the higher the degradation (D) is evaluated.

[0075] Degradation diagnostic information (Info(D(i))) according to the degree of degradation (D(i)) of the secondary battery (220) is generated by the battery performance evaluation element (130) (Fig. 2 / STEP 132). By the battery performance evaluation element (130), the diagnostic information (Info(D(i))) is transmitted from the battery performance evaluation device (100) to the target device (200) (Fig. 2 / STEP 134).

[0076] In the target device (200), degradation diagnosis information (Info(D(i))) is received by a receiving device constituting an input interface (202) (Fig. 2 / STEP 222). The degradation diagnosis information (Info(D(i))) is displayed on a display device constituting an output interface (204) (Fig. 2 / STEP 224). Accordingly, in addition to a graph displaying the degradation level (D(i)) of the secondary battery (220), a message regarding countermeasures according to the degradation level (D(i)), such as 'The degradation level of the battery is 30%. It is recommended to replace it after 150 days,' is displayed on the display device.

[0077] (Other embodiments of the present invention)

[0078] In the above embodiment, the first battery model and / or the second battery model are selected after the temperature (T) at the time of measuring the voltage response characteristics (V(t)) of each of the reference secondary battery and the target secondary battery is taken into account, and the performance of the secondary battery (220) as the target secondary battery is evaluated. Meanwhile, in another embodiment, the temperature (T) at the time of measuring the voltage response characteristics (V(t)) of each of the reference secondary battery and the target secondary battery is not taken into account, and the first battery model and / or the second battery model are selected based on an identifier indicating the specifications of the target secondary battery, and the performance of the secondary battery (220) as the target secondary battery is evaluated. Explanation of the symbols

[0079] 10 : Database 100 : Battery performance evaluation device 111 : 1st recognition processing element 112 : 2nd recognition processing element 121 : 1st operation processing element 122 : 2nd operation processing element 130 : Battery performance evaluation factors 200 : Target device 202: Input Interface 204: Output Interface 210 : Control unit 220 : Secondary battery 221 : Reference secondary battery 222 : Target secondary battery 230 : Sensor group

Claims

Claim 1 A first recognition processing element that recognizes the measurement result of the impedance of a reference secondary battery; a first computation processing element that, based on the measurement result of the impedance of the reference secondary battery recognized by the first recognition processing element, determines a first battery model defined by a plurality of first model parameters by identifying the values ​​of each of a plurality of first model parameters if a designated condition is not satisfied, and determines a second battery model defined by a plurality of second model parameters by identifying the values ​​of each of a plurality of second model parameters that are a minority of the plurality of first model parameters if the designated condition is satisfied; a second recognition processing element that recognizes the actual output voltage as the measurement result of the change pattern of the voltage output from the target secondary battery when a designated current is input to the target secondary battery having the same specifications as the reference secondary battery; and a second method that specifies the model output voltage as the change pattern of the voltage output from the first battery model or the second battery model when the designated current is input to the first battery model or the second battery model determined by the first computation processing element. A battery performance evaluation device comprising a computational processing element and a battery performance evaluation element that evaluates the performance of the target secondary battery based on a comparison result between the actual output voltage recognized by the second recognition processing element and the model output voltage specified by the second computational processing element, wherein each of the first model parameter and the second model parameter includes a parameter that defines a Warburg impedance, and the parameter that defines the Warburg impedance as part of the second model parameter is common to the parameter that defines the Warburg impedance as part of the first model parameter. Claim 2 A battery performance evaluation device according to claim 1, wherein the first recognition processing element recognizes the measurement result of the impedance at each of the different temperatures of the reference secondary battery, and the first computation processing element determines the first battery model by specifying the temperature dependency of each of the values ​​of the plurality of first model parameters based on the measurement result of the impedance at each of the different temperatures of the reference secondary battery recognized by the first recognition processing element if the specified condition is not satisfied, and determines the second battery model by specifying the temperature dependency of each of the values ​​of the plurality of second model parameters if the specified condition is satisfied, and the second recognition processing element recognizes the measurement result of the temperature of the target secondary battery in addition to the output voltage of the target secondary battery, and the second computation processing element determines the model output voltage when the measurement result of the temperature of the target secondary battery recognized by the second recognition processing element is input in addition to the specified current for the first battery model or the second battery model determined by the first computation processing element. Claim 3 A battery performance evaluation device that establishes the first battery model or the second battery model as at least one of the specified conditions, wherein, in claim 1 or 2, the first computational processing element is composed of a low-frequency current component in which the specified current is lower than the reference frequency, and the computational processing load of the first computational processing element is greater than or equal to a reference value. Claim 4 A first recognition processing process that recognizes the measurement result of the impedance of a reference secondary battery by a first recognition processing element; a first computation processing process that, based on the measurement result of the impedance of the reference secondary battery recognized in the first recognition processing process by a first computation processing element, determines a first battery model defined by a plurality of first model parameters by identifying the value of each of a plurality of first model parameters if a designated condition is not satisfied, and determines a second battery model defined by a plurality of second model parameters by identifying the value of each of a plurality of second model parameters that is a minority of the plurality of first model parameters if the designated condition is satisfied; a second recognition processing process that recognizes the actual output voltage as a measurement result of the change pattern of the voltage output from a target secondary battery when a designated current is input to a target secondary battery having the same specifications as the reference secondary battery by a second recognition processing element; and a second computation processing element that, for the first battery model or the second battery model determined in the first computation processing process, when the designated current is input, the first battery model or the A battery performance evaluation method comprising: a second computational processing process for specifying a model output voltage as a change pattern of voltage output from a second battery model; and a battery performance evaluation process for evaluating the performance of a target secondary battery based on a comparison result between the actual output voltage recognized in the second recognition processing process by the second recognition processing element and the model output voltage specified in the second computational processing process by the second computational processing element, wherein each of the first model parameter and the second model parameter includes a parameter defining a Warburg impedance, and the parameter defining a Warburg impedance as part of the second model parameter is common to the parameter defining a Warburg impedance as part of the first model parameter.

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