JP6551778B2 - Deterioration determination device and deterioration determination method for storage element - Google Patents

Description

  The present invention relates to a deterioration determination device and a deterioration determination method of a storage element capable of determining the capacity deterioration of a storage element from resistance.

  Conventionally, a secondary battery performance estimation method for diagnosing secondary battery performance (capacity deterioration rate) is known (see Patent Document 1). In this performance estimation method, the cell casing of the secondary battery is hit with a hammer, the magnitude of the vibration of the cell casing due to the hit is measured, and the waveform indicating the measured vibration is analyzed to analyze the cell casing. And the performance (capacity deterioration rate) of the secondary battery is estimated based on the calculated resonance frequency.

  However, since the method for estimating the performance of the secondary battery needs to hit the cell casing with the hammer, the secondary battery is used as a power source every time the performance of the secondary battery is diagnosed. It was necessary to remove it from the device etc., which was complicated.

JP 2014-122817 A

  Accordingly, an object of the present invention is to provide a storage element deterioration determination device and a deterioration determination method capable of determining the capacity deterioration of a storage element without removing the storage element from a device that uses the storage element as a power source. To do.

  In the electric storage element, there are a plurality of performance deterioration modes, that is, a deterioration mode A and a deterioration mode B different from the deterioration mode A. In this power storage element, when the deterioration mode A is shifted to the deterioration mode B, the capacity deterioration of the power storage element proceeds rapidly (see FIG. 5). For this reason, it is necessary to detect this change (development of the deterioration mode B) at an early stage and notify the user that the power storage element has deteriorated.

  The inventors of the present invention have intensively studied to solve the above problems, and as a result, there is a correlation between the resistance and temperature of the storage element in a predetermined state of charge (SOC) (that is, temperature dependence of resistance). When the deterioration mode B is developed in the storage element by approximating the function and leaving the storage element, the shape of the quadratic curve representing the quadratic function approximating the correlation changes greatly (for example, FIG. 5 and FIG. 7 to FIG. 9), and based on these, it was found that the deterioration of the storage element can be accurately determined (that is, whether or not the capacity deterioration of a predetermined amount or more has occurred). .

  Therefore, based on this knowledge, the inventors approximate a quadratic function to the correlation between the resistance and temperature of the storage element in a predetermined state of charge (SOC) (that is, temperature dependence of resistance). Focusing on the quadratic function (that is, the shape of the quadratic curve obtained from the quadratic function), the present inventors have created a deterioration determination device and a deterioration determination method for a storage element having the following configuration.

According to the storage device deterioration determination device of the present invention,
A detection unit for detecting each of the resistances of the storage elements at different temperatures from the storage elements in a predetermined charge state;
An expression derivation unit for deriving a quadratic function approximated to the correlation between the resistance and temperature detected by the detection unit;
And a determination unit that determines deterioration of the storage element based on the quadratic function.

  According to such a configuration, a quadratic function approximated to the correlation between the resistance of the power storage element and the temperature can be obtained by detecting the resistance of the power storage element at a plurality of different temperatures. Whether or not the degradation mode B is expressed can be accurately determined. Therefore, it is possible to accurately determine the deterioration of the power storage element without removing the power storage element from a device or the like that uses the power storage element as a power source.

Specifically,
The quadratic function derived by the equation deriving unit is y = ax ² + bx + c (a, b, and c are coefficients),
The determination unit may determine deterioration of the power storage element based on at least one of a, b, and c that are coefficients of the quadratic function.

  According to this configuration, since the determination unit determines based on the coefficient of the quadratic function derived by the equation deriving unit, it can easily and accurately determine the deterioration of the storage element.

in this case,
The determination unit preferably determines that the storage element is deteriorated when b / a or b / c, which is a ratio of the coefficients, is equal to or greater than a predetermined threshold.

  By determining the ratio of the coefficients of the quadratic function in this manner, the change in the shape of the quadratic curve appears more greatly, so that deterioration of the power storage element can be determined more easily and more accurately.

Moreover, the deterioration determination device of a storage element according to the present invention is:
A storage unit storing determination data used to determine the presence or absence of deterioration of the storage element;
A determination unit that determines presence or absence of deterioration of the storage element using the determination data of the storage unit;
The determination data includes the resistance and temperature of the storage element when a quadratic function y = ax ² + bx + c approximated to the correlation between the resistance of the storage element and temperature is derived for each deterioration state of the storage element. And the presence or absence of deterioration of the electricity storage element based on the deterioration state determined based on at least one of the coefficients a, b, and c of the quadratic function y = ax ² + bx + c. ,
The determination unit determines deterioration of the determination target storage element by finding from the determination data a combination of the resistance and temperature including the resistance and temperature detected from the determination target storage element.

According to this configuration, the determination data (the storage element when the quadratic function y = ax ² + bx + c approximated to the correlation between the resistance of the storage element and the temperature for each deterioration state of the storage element is derived in advance. The presence or absence of deterioration of the electricity storage element based on the deterioration state determined based on at least one of the resistance and temperature pair and the coefficients a, b, and c of the quadratic function y = ax ² + bx + c (ie, suitable for use) Is stored in the storage unit, the determination is made by simply detecting the resistance (resistance value) and the temperature from the determination target storage element. It is possible to easily and reliably determine the deterioration state of the target power storage element (that is, whether or not the state is suitable for use).

Further, the method of determining deterioration of a storage element according to the present invention is:
Detecting the resistance of the storage element at a plurality of different temperatures from the storage element in a predetermined charge state;
Deriving a quadratic function approximated to the correlation between the detected resistance and temperature;
Determining the deterioration of the storage element based on the derived quadratic function.

  According to such a configuration, a quadratic function approximated to the correlation between the resistance of the power storage element and the temperature can be obtained by detecting the resistance of the power storage element at a plurality of different temperatures. It is possible to accurately determine whether or not the deterioration mode B is exhibited. Therefore, it is possible to accurately determine the deterioration of the power storage element without removing the power storage element from a device or the like that uses the power storage element as a power source.

  As described above, according to the present invention, there is provided a storage element deterioration determination device and a deterioration determination method capable of determining the capacity deterioration of a storage element without removing the storage element from a device that uses the storage element as a power source. Can do.

FIG. 1 is a perspective view of a storage element to be determined by the deterioration determination apparatus according to the present embodiment. FIG. 2 is an exploded perspective view of the power storage element. FIG. 3 is a view for explaining an electrode body of the electricity storage element. FIG. 4 is a schematic configuration diagram of the deterioration determination apparatus. FIG. 5 is a diagram showing the relationship between the capacity deterioration of the storage element and the leaving period. FIG. 6 is a diagram showing a correlation between resistance and temperature detected from a storage element having a predetermined SOC and a quadratic curve approximated to this correlation. FIG. 7 is a diagram showing the relationship between the coefficient a of the quadratic function (y = ax ² + bx + c) defining the quadratic curve and the storage period of the storage element. FIG. 8 is a diagram showing the relationship between the coefficient b of the quadratic function and the storage period of the storage element. FIG. 9 is a diagram illustrating the relationship between the coefficient c of the quadratic function and the storage period of the storage element. FIG. 10 is a diagram illustrating the relationship between the coefficient ratio b / a of the quadratic function and the storage period of the storage element. FIG. 11 is a diagram showing the relationship between the coefficient ratio b / c of the quadratic function and the storage period of the storage element. FIG. 12 is a flowchart for determining deterioration of a storage element by the deterioration determination apparatus.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 12. In addition, the name of each component (each component) of this embodiment is a thing in this embodiment, and may differ from the name of each component (each component) in background art.

  The storage element degradation determination device (hereinafter simply referred to as “determination device”) according to the present embodiment is mounted on, for example, a hybrid vehicle driven by an engine and a motor, and the storage element mounted on the hybrid vehicle Determine capacity degradation. Below, the electrical storage element which is the determination object of the capacity | capacitance deterioration by a determination apparatus is demonstrated first.

  As shown in FIGS. 1 to 3, the power storage element includes an electrode body 102 including a positive electrode 123 and a negative electrode 124, a case 103 that houses the electrode body 102, and an external terminal 104 that is disposed outside the case 103. Prepare. In addition, the storage element 100 also includes a current collector 105 and the like that electrically connect the electrode body 102 to the external terminal 104.

  The electrode body 102 includes a winding core 121 and a positive electrode 123 and a negative electrode 124 wound around the winding core 121 in a state of being insulated from each other. As the lithium ions move between the positive electrode 123 and the negative electrode 124 in the electrode body 102, the power storage element 100 is charged and discharged.

  The positive electrode 123 has a metal foil and a positive electrode active material layer formed on the metal foil. The metal foil is strip-shaped. The metal foil of this embodiment is an aluminum foil, for example.

  The negative electrode 124 has a metal foil and a negative electrode active material layer formed on the metal foil. The metal foil is strip-shaped. The metal foil of this embodiment is a copper foil, for example.

  In the electrode body 102 of the present embodiment, the positive electrode 123 and the negative electrode 124 configured as described above are wound in a state where they are insulated by the separator 125. That is, in the electrode body 102 of this embodiment, the positive electrode 123, the negative electrode 124, and the separator 125 are wound in a stacked state. The separator 125 is an insulating member. The separator 125 is disposed between the positive electrode 123 and the negative electrode 124. Thereby, in the electrode body 102, the positive electrode 123 and the negative electrode 124 are mutually insulated. Further, the separator 125 holds the electrolytic solution in the case 103. Accordingly, during charging / discharging of the electricity storage element 100, lithium ions move between the positive electrode 123 and the negative electrode 124 that are alternately stacked with the separator 125 interposed therebetween.

  The case 103 includes a case main body 131 having an opening and a cover plate 132 that closes (closes) the opening of the case main body 131. The case 103 is formed by joining the opening peripheral part 136 of the case main body 131 and the peripheral part of the cover plate 132 in a state of being overlapped. The case 103 has an internal space defined by a case body 131 and a cover plate 132. Then, the case 103 accommodates the electrolytic solution in the inner space together with the electrode body 102, the current collector 105, and the like.

  The case main body 131 includes a rectangular plate-shaped blocking part 134 and a rectangular tube-shaped body part 135 connected to the periphery of the blocking part 134. That is, the case main body 131 has a rectangular tube shape (that is, a bottomed rectangular tube shape) in which one end portion in the opening direction (Z-axis direction) is closed.

  The lid plate 132 is a plate-like member that closes the opening of the case main body 131. Specifically, the cover plate 132 has a contour shape corresponding to the opening peripheral edge 136 of the case main body 131. That is, the cover plate 132 is a rectangular plate material. In the lid plate 132, the periphery of the cover plate 132 is overlapped with the opening periphery 136 of the case body 131 so as to close the opening of the case body 131. In the following, as shown in FIG. 1, the long side direction of the cover plate 132 is the X-axis direction in the orthogonal coordinates, the short side direction of the cover plate 132 is the Y-axis direction in the orthogonal coordinates, and the normal direction of the cover plate 132 is the normal direction. It is set as the Z-axis direction in orthogonal coordinates.

  The external terminal 104 is a portion electrically connected to an external terminal of another storage element, an external device, or the like. The external terminal 104 is formed of a conductive member. For example, the external terminal 104 is formed of a highly weldable metal material such as an aluminum-based metal material such as aluminum or an aluminum alloy, or a copper-based metal material such as copper or a copper alloy.

  The current collector 105 is disposed in the case 103 and is directly or indirectly connected to the electrode body 102 so as to be energized. The current collector 105 is formed of a conductive member and is disposed along the inner surface of the case 103.

  The storage element 100 includes an insulating member 106 that insulates the electrode body 102 from the case 103. The insulating member 106 of this embodiment is bag-shaped. The insulating member 106 is disposed between the case 103 (specifically, the case main body 131) and the electrode assembly 102. The insulating member 106 of the present embodiment is formed of a resin such as polypropylene or polyphenylene sulfide, for example.

  Next, a determination device for determining the capacity deterioration of the storage element 100 will be described with reference to FIGS. 4 to 12 as well.

  As shown in FIG. 4, the determination device detects a resistance of the storage element 100 at a plurality of different temperatures from the storage element 100 of a predetermined SOC (charged state), and the detection unit 2 detects the resistance. An equation deriving unit 3 for deriving a quadratic function approximated to the correlation between the resistance and temperature, and a determination unit 4 for determining deterioration of the storage element 100 based on the quadratic function derived by the equation deriving unit 3; . The determination device 1 also includes an output unit 5 and the like that output the determination result of the determination unit 4 to the outside. The determination device 1 according to the present embodiment determines the capacity deterioration of each of the plurality of power storage elements 100 mounted on the hybrid vehicle. In addition, the determination apparatus 1 may not have the detection unit 2 and may be configured to acquire the resistance and the temperature from a measuring instrument or the like installed for other purposes.

  The detection unit 2 includes a resistance detection unit 21 that detects the resistance of the storage element 100 having a predetermined SOC, and a temperature detection unit 22 that detects the temperature of the storage element 100. Resistance detection unit 21 and temperature detection unit 22 detect the resistance and temperature of storage element 100 at the same timing. The temperature detection unit 22 detects the temperature of a part of the case 103 of the power storage device 100 (for example, the cover plate 132, the blocking unit 134, the long side surface or the short side surface of the body unit 135). The resistance detection unit 21 and the temperature detection unit 22 of the present embodiment are provided for each of the plurality of storage elements 100. Note that the temperature detection unit 22 may be configured to measure the temperature of some of the plurality of power storage elements 100.

  Specifically, the resistance detection unit 21 detects the resistance multiple times at intervals with respect to the storage element 100 having a predetermined SOC. The resistance detection unit 21 of the present embodiment calculates a resistance (resistance value) based on Ohm's law from the current value generated in the storage element 100 and the voltage value of each storage element 100. That is, the resistance detection unit 21 of this embodiment includes one ammeter 211 and voltmeters 212 corresponding to the number of power storage elements 100. Further, the temperature detection unit 22 detects the temperature of the storage element 100 at the same timing as the resistance detection unit 21. At this time, the temperature of the storage element 100 is changed in order to detect resistance at different temperatures. For the change of the temperature of the storage element 100, the determination device 1 may be provided with a configuration for changing the temperature of the storage element 100, or another device may be used. The detection unit 2 may be configured such that the temperature detection unit 22 continues to detect the temperature of the storage element 100, and the resistance detection unit 21 detects the resistance when the storage element 100 has a plurality of different temperatures.

  The resistance detection unit 21 outputs the detected resistance (resistance value) to the formula derivation unit 3 as a resistance signal. Further, the temperature detection unit 22 outputs the detected temperature of the storage element 100, specifically, the temperature of the storage element 100 when the current is detected by the resistance detection unit 21 to the equation deriving unit 3 as a temperature signal.

The expression deriving unit 3 derives a quadratic function approximated to the correlation between the resistance detected from the storage element 100 having a predetermined SOC and the temperature: y = ax ² + bx + c (a, b, and c are coefficients). The equation deriving unit 3 derives a quadratic function (y = ax ² + bx + c) based on the resistance signal from the resistance detecting unit 21 and the temperature detecting unit 22 and the temperature signal. For example, the formula deriving unit 3 of the present embodiment determines a quadratic curve that approximates a graph plotting the relationship between a plurality of resistances detected from the storage element 100 and the temperature corresponding to each resistance (see FIG. 6). A quadratic function (y = ax ² + bx + c) that defines this quadratic curve is derived. Then, the expression deriving unit 3 outputs the derived quadratic function (y = ax ² + bx + c) to the determination unit 4 as a function signal.

The determination unit 4 determines the deterioration of the storage element 100 based on at least one of the coefficients a, b and c of the quadratic function (y = ax ² + bx + c). The determination unit 4 of the present embodiment determines the capacity deterioration of the storage element 100. The determination unit 4 determines the deterioration of the storage element 100 based on the function signal from the equation derivation unit 3. Specifically, the determination unit 4 determines the deterioration of the power storage element 100 based on the ratio b / a or b / c of the quadratic function coefficient. For example, when the ratio b / a of the quadratic function coefficient is equal to or greater than a predetermined threshold value (−5.7 in the example of the present embodiment), the determination unit 4 of the present embodiment deteriorates the power storage element 100. It is determined that there is. On the other hand, when the ratio b / a of the quadratic function coefficient is smaller than the threshold value, the determination unit 4 determines that the power storage element 100 has not deteriorated. The specific principle (reason) of this determination is as follows.

  The storage element 100 has a plurality of deterioration modes, that is, a deterioration mode A and a deterioration mode B different from the deterioration mode A. In this power storage element 100, when the deterioration of the power storage element 100 increases, a deterioration mode B different from the deterioration mode (deterioration mode A) during normal use appears, and therefore the deterioration of the power storage element 100 proceeds rapidly ( (See FIG. 5).

When the storage element 100 is left for a long period of time, when a deterioration mode B different from the deterioration mode A of the storage element 100 appears, the correlation between the resistance obtained from the storage element 100 of a predetermined SOC and the temperature is obtained. Coefficients a, b, and c of the quadratic function derived based on the quadratic function approximated to the correlation between the resistance and temperature (y = ax ² + bx + c: see FIG. 6) also change abruptly (see FIG. 7 to 9), in other words, the shape of the quadratic curve defined by the quadratic function (y = ax ² + bx + c) changes significantly. For this reason, the storage element depends on the rate of change of the coefficients a, b, c in FIGS. 7-9 (the slopes of the graphs in FIGS. 7-9) and whether the coefficients a, b, c exceed a predetermined threshold. At 100, it can be easily judged whether the degradation mode B is expressed.

Further, as shown in FIGS. 7 to 9, the coefficients a, b, and c of the quadratic function (y = ax ² + bx + c) change abruptly after the deterioration mode B appears in the power storage device 100. With these ratios (ratios of coefficients) b / a or b / c, as shown in FIGS. 10 and 11, the change after the occurrence of the degradation mode B becomes larger. Therefore, by using the coefficient ratio b / a or b / c of the quadratic function (y = ax ² + bx + c), the presence or absence of the deterioration mode B in the power storage element 100 is determined more accurately and reliably. be able to.

  The determination unit 4 that has determined the deterioration (capacity deterioration) of the storage element 100 in this way outputs the determination result to the output unit 5 as a result signal.

  The output unit 5 outputs the determination result of the determination unit 4 to the outside based on the result signal from the determination unit 4. The output unit 5 of the present embodiment is a display device such as a monitor and displays whether or not the power storage element 100 has deteriorated. The output unit 5 is not limited to the configuration that outputs the determination result to the outside according to an image, and is a sound output device such as a speaker that outputs a warning sound such as a buzzer when it is determined that the storage element 100 is degraded. It may be a character output device such as a printer that prints out characters and the like. The output unit 5 may be configured to have a plurality of output methods, for example, outputting the determination result of the determination unit 4 using an image and sound.

  Next, determination of deterioration of the storage element 100 by the determination device 1 will be described with reference to FIG.

  When the storage element 100 has a predetermined SOC, the detection unit 2 detects the resistance of the storage element 100 at a plurality of temperatures (step S1), and outputs the detection result to the equation deriving unit 3. For example, the determination device 1 of the present embodiment detects the resistance and temperature of the power storage element 100 when the SOC is lower than 50% SOC (low SOC).

When the resistance of the electricity storage element 100 at a plurality of temperatures is detected by the detection unit 2, the equation deriving unit 3 approximates a correlation between the detected resistance and temperature (y = ax ² + bx + c: A, b, c are coefficients) are derived (step S2), and the derivation result is output to the determination unit 4.

Subsequently, the determination unit 4 determines whether or not the power storage element 100 has deteriorated based on the coefficients a, b, and c of the quadratic function (y = ax ² + bx + c) derived by the equation deriving unit 3. The determination unit 4 of the present embodiment determines the capacity deterioration of the power storage element 100 based on whether or not the coefficient ratio b / a is greater than or equal to a threshold value (−5.7 in the example of the present embodiment) (step S3). The determination result is output to the output unit 5. Specifically, the determination unit 4 determines that when the coefficient ratio b / a is equal to or greater than the threshold value, the capacity deterioration of the power storage element 100 has progressed to a state not suitable for use of the power storage element 100, and The determination result that the element 100 is deteriorated is output to the output unit 5. On the other hand, when the ratio b / a of the coefficient is smaller than the threshold value, the determination unit 4 determines that the capacity deterioration of the power storage element 100 has not progressed to a state that is not suitable for use of the power storage element 100, and the power storage element 100 The determination result that it has not deteriorated is output to the output unit 5.

  The output unit 5 displays (outputs to the outside) the determination result by the determination unit 4 as an image (step S4). Based on this display, the driver or the like determines whether to continue using the storage element 100 or replace the storage element.

According to the above-described degradation determination device 1 and degradation determination method for an electrical storage element, the resistance of the electrical storage element 100 at a plurality of different temperatures is detected to approximate the correlation between the resistance of the electrical storage element 100 and the temperature. A quadratic function (y = ax ² + bx + c: a, b, and c are coefficients) is obtained, whereby it is possible to accurately determine whether or not the deterioration mode B is manifested in the power storage element 100. Therefore, without removing the storage element 100 from a device such as a hybrid vehicle that uses the storage element 100 as a power supply, deterioration of the storage element 100 can be determined with high accuracy.

In the determination apparatus 1 of the above embodiment, the determination unit 4 determines based on the coefficients a, b, and c of the quadratic function (y = ax ² + bx + c) derived by the equation deriving unit 3, so that the storage element The deterioration of 100 can be determined easily and accurately.

  In addition, the determination unit 4 uses the coefficient ratio b / a in which the change in the shape of the quadratic curve appears larger (specifically, the coefficient ratio b / a and the threshold (−5.7)). Since the deterioration of the storage element 100 is determined (by comparison), the deterioration of the storage element 100 can be determined more easily and more accurately.

  It should be noted that the storage element deterioration determination device and the deterioration determination method of the present invention are not limited to the above-described embodiment, and various changes can be made without departing from the scope of the present invention. For example, the configuration of another embodiment can be added to the configuration of a certain embodiment, and a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment. Furthermore, a part of the configuration of an embodiment can be deleted.

In the degradation determination device 1 of the above embodiment, the determination unit 4 compares the coefficient ratio b / a of the quadratic function (y = ax ² + bx + c) with a threshold value (−5.7 in the example of the above embodiment). Although the deterioration of the storage element 100 is determined, the present invention is not limited to this configuration. When degraded mode B appears in the capacitor 100, the two defined by the quadratic function ^{(y = ax 2 + bx +} c) coefficient a, b, c greatly changes (i.e., a quadratic function ^{(y = ax 2 + bx +} c) Since the shape of the quadratic curve greatly changes (see FIGS. 7 to 9), the determination unit 4 determines based on at least one of the coefficients a, b, and c of the quadratic function (y = ax ² + bx + c). do it.

  Also, as shown in FIGS. 10 and 11, the coefficient ratio b / c also changes abruptly after the deterioration mode B appears in the power storage device 100, similarly to the coefficient ratio b / a. 4 may be configured to use the coefficient ratio b / c for determination of deterioration.

  Moreover, the apparatus etc. in which the degradation determination apparatus 1 is mounted (arranged) are not limited to a hybrid vehicle. An apparatus or the like on which the degradation determination apparatus 1 is mounted (arranged) may be any apparatus that mounts (arranges) the storage element 100 so as to be chargeable / dischargeable. In addition, the deterioration determination device 1 may be configured to be used alone without being mounted on the device or the like.

Further, in the deterioration determination device 1 of the above embodiment, a quadratic function (y = ax ² + bx + c) is derived, and deterioration of the power storage element 100 is determined based on at least one of the coefficients a, b, and c. However, it is not limited to this configuration. For example, the deterioration determination device 1 stores determination data such as a map and a table in a storage unit (hard disk, memory, etc.), and determines deterioration (whether it is suitable for use) of the power storage element 100 based on the determination data. It may be configured to determine.

For example, specifically, the deterioration determination device includes a storage unit that stores determination data used for determining whether or not the storage element has deteriorated, and a determination that determines whether or not the storage element has deteriorated using the determination data of the storage unit. And a unit. In this deterioration determination device, the determination data stored in the storage unit is a quadratic function (y = ax ² + bx + c) approximated to the correlation between the resistance of the storage element and the temperature for each deterioration state of the storage element. The electrical storage based on the degradation state determined based on at least one of the combination of the resistance and temperature of the electrical storage element and the coefficients a, b, and c of the quadratic function (y = ax ² + bx + c) It relates the availability of the element. Then, the determination unit finds the combination of the resistance and temperature including the resistance and temperature detected from the determination target storage element 100 from the determination data stored in the storage unit, and corresponds to the combination of the resistance and temperature. From the presence or absence of deterioration of the storage element, the presence or absence of the deterioration of the storage element 100 to be determined is determined.

  According to such a configuration, since the determination data is stored in the storage unit in advance, the deterioration state (that is, the determination target storage element (that is, the resistance value) and the temperature are detected only from the determination target storage element (that is, the determination target storage element) Can be determined easily and reliably.

  In addition, for example, when the deterioration determination device is mounted on a vehicle or the like together with the power storage element 100 (or a power storage device including the power storage element 100), it is determined that the power storage element (determination target power storage element) 100 is deteriorated. The operation condition of the electricity storage device 100 may be changed (limited) so that the electricity storage device 100 does not deteriorate any more. Specifically, when the deterioration determination device determines that the electric storage element 100 is progressing in the direction of deterioration (a chemical reaction progresses (not desired to occur) in the electric storage element 100), the deterioration determination device avoids the deterioration. The operating conditions of the storage element 100 are changed (limited). In addition, the deterioration determination device may be configured to contact a user, a dealer, or the like (or transmit data to a vehicle manufacturer's data center or the like) when it is determined that the deterioration is proceeding in the direction of deterioration. .

  DESCRIPTION OF SYMBOLS 1 ... Degradation determination apparatus, 2 ... Detection part, 21 ... Resistance detection part, 211 ... Ammeter, 212 ... Voltmeter, 22 ... Temperature detection part, 3 ... Formula derivation part, 4 ... Determination part, 5 ... Output part, 100 DESCRIPTION OF SYMBOLS ... Storage element, 102 ... Electrode body, 103 ... Case, 104 ... External terminal, 105 ... Current collector, 106 ... Insulating member, 121 ... Core, 123 ... Positive electrode, 124 ... Negative electrode, 125 ... Separator, 131 ... Case body , 132: lid plate, 134: closing portion, 135: body portion, 136: opening peripheral portion

Claims (7)

A detection unit for detecting each of the resistances of the storage elements at different temperatures from the storage elements in a predetermined charge state;
An equation deriving unit for deriving a quadratic function fitted to a plot of the logarithm of the resistance detected by the detection unit and the inverse of the temperature;
And a determination unit that determines deterioration of the storage element based on a change in the shape of a quadratic curve defined by the quadratic function. The quadratic function derived by the equation deriving unit is y = ax ² + bx + c (a, b, and c are coefficients),
The storage element deterioration determination device according to claim 1, wherein the determination unit determines the deterioration of the storage element based on at least one of a, b, and c that are coefficients of the quadratic function.   The determination unit according to claim 2, wherein the determination unit determines that the storage element is deteriorated when b / a or b / c, which is a ratio of the coefficients, is equal to or greater than a predetermined threshold. apparatus. A storage unit storing determination data used to determine the presence or absence of deterioration of the storage element;
A determination unit that determines presence or absence of deterioration of the storage element using the determination data of the storage unit;
The determination data includes the resistance and temperature of the storage element when a quadratic function y = ax ² + bx + c approximated to the correlation between the resistance of the storage element and temperature is derived for each deterioration state of the storage element. And the presence or absence of deterioration of the electricity storage element based on the deterioration state determined based on at least one of the coefficients a, b, and c of the quadratic function y = ax ² + bx + c. ,
The determination unit determines deterioration of the determination target storage element by finding a combination of the resistance and temperature including the resistance and temperature detected from the determination target storage element from the determination data. Deterioration judging device. A detection unit for detecting each of the resistances of the storage elements at different temperatures from the storage elements in a predetermined charge state;
An expression derivation unit for deriving a quadratic function approximated to the correlation between the resistance and temperature detected by the detection unit;
A determination unit that determines the deterioration of the storage element based on the quadratic function ;
The quadratic function derived by the equation deriving unit is y = ax ² + bx + c (a, b, and c are coefficients),
The determination unit, when a ratio of the coefficient b / a or b / c is not smaller than a predetermined threshold value, you determined that the electric storage device is deteriorated, the deterioration determination device of the storage element. Detecting the resistance of the storage element at a plurality of different temperatures from the storage element in a predetermined charge state;
Deriving a quadratic function approximated to the correlation between the detected resistance and temperature;
Determining the deterioration of the storage element based on the derived quadratic function .
The derived quadratic function is y = ax ² + bx + c (a, b, and c are coefficients),
In the above determination, when the ratio of the coefficient b / a or b / c is not smaller than a predetermined threshold value, it determined that the electric storage device is deteriorated,
Method of determining deterioration of storage element. Detecting the resistance of the storage element at a plurality of different temperatures from the storage element in a predetermined charge state;
Deriving a quadratic function that fits a plot of the logarithm of the detected resistance and the inverse of temperature;
Determining the deterioration of the storage element based on a change in the shape of a quadratic curve defined by the derived quadratic function.