JP2014049401A - Battery state estimation device, vehicle including the battery state estimation device, and battery state estimation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and method for estimating a battery state, improved in estimation accuracy of a battery state.SOLUTION: A battery state estimation device includes: a battery 1 including a power generation element sealed inside an outer packaging member; a first sensor disposed on a surface of the outer packaging body and detecting an oscillating wave propagating in the battery 1; a measurement means for measuring the hardness of the battery 1 from a detected value of the first sensor; and a battery state estimation means for estimating the state of the battery 1 from a measured value obtained by the measurement means, on the basis of the relation between the hardness of the battery 1 and the state of the battery 1.

Description

  The present invention relates to a battery state estimation device and a vehicle.

  The battery voltage to be measured when charging / discharging with various currents at various temperatures of a normal secondary battery that has not deteriorated, and basic data that is data on the amount of stored electricity or the amount of discharge are obtained in advance. Measuring the voltage value or voltage value and current value of the secondary battery being compared, and comparing with the basic data, the secondary battery to be detected determines a decrease in the storage capacity. It is known to detect the internal state of a battery (Patent Document 1).

JP 2002-50410 A

  However, as in the case of the secondary battery detection device described above, the comparison of the basic data of the battery that has not been deteriorated and the voltage value of the secondary battery in use, etc., changes the usage conditions. There has been a problem that the state of cannot be accurately detected.

  The problem to be solved by the present invention is to provide a battery state estimation device and a battery state estimation method that improve the estimation accuracy of the state of the battery.

  The present invention measures the hardness of the battery from the detection value of the first sensor that detects the vibration wave in the battery, and estimates the state of the battery from the measurement value based on the relationship between the hardness of the battery and the state of the battery. This solves the above problem.

  The present invention makes it possible to estimate the state of the battery regardless of the past use conditions of the battery by utilizing the relationship between the hardness of the battery and the state of the battery, and thus increases the estimation accuracy of the state of the battery. Can do.

It is a block diagram of the battery state estimation apparatus which concerns on embodiment of this invention. It is a top view of the battery of FIG. It is sectional drawing which follows AA of FIG. It is a top view of the battery and ultrasonic sensor of FIG. 2 is a graph showing characteristics of battery capacity with respect to the number of cycles in the battery of FIG. 1. In the battery of FIG. 1, it is a graph which shows the ratio of the hardness of the battery with respect to the state of a battery. In the battery of FIG. 1, it is a graph which shows the ratio of the hardness of the battery with respect to the state of a battery. In the battery of FIG. 1, it is a figure for demonstrating the propagation time of the ultrasonic wave which propagates the inside of a battery. 2 is a graph showing a propagation time characteristic with respect to the number of cycles in the battery of FIG. 1. 2 is a graph showing a characteristic of propagation time with respect to capacity reduction in the battery of FIG. It is a flowchart which shows the control procedure of the controller of FIG. It is a perspective view of the battery and ultrasonic sensor of the battery state estimation apparatus which concerns on the modification of this invention. It is a perspective view of the transmitter of the battery state estimation apparatus which concerns on the modification of this invention. It is sectional drawing which follows the BB line of FIG. It is a block diagram of the battery state estimation apparatus which concerns on other embodiment of this invention. 16 is a graph showing inertance characteristics with respect to frequency in the battery of FIG. 15. 16 is a graph showing characteristics of a reduction rate of discharge capacity with respect to a resonance frequency in the battery of FIG. It is a flowchart which shows the control procedure of the controller of FIG. It is a graph which shows the characteristic of the coherence with respect to a frequency in the battery of the battery state estimation apparatus which concerns on other embodiment of this invention. It is a flowchart which shows the control procedure of the controller of the battery state estimation apparatus which concerns on other embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<< First Embodiment >>
FIG. 1 is a block diagram of a battery state estimation device according to an embodiment of the present invention. The battery state estimation device of this example is mounted on a vehicle or the like.

  The battery state estimation device includes a flat battery 1, an ultrasonic sensor 2, and a controller 3. The structure of the battery 1 is demonstrated using FIG.2 and FIG.3. FIG. 2 is a plan view of the flat battery 1, and FIG. 3 is a cross-sectional view taken along the line AA in FIG. The flat battery 1 is a lithium ion-based, flat-plate, laminate-type secondary battery (thin battery). As shown in FIGS. 2 and 3, three positive plates 11 and five sheets are provided. The separator 12 includes three negative plates 13, a positive electrode tab 14 (positive electrode terminal), a negative electrode tab 15 (negative electrode terminal), an upper exterior member 16, a lower exterior member 17, and an electrolyte (not shown). ing.

  Among these, the positive electrode plate 11, the separator 12, the negative electrode plate 13 and the electrolyte constitute a power generation element 18, the positive electrode plate 11 and the negative electrode plate 13 constitute an electrode plate, and the upper exterior member 16 and the lower exterior member 17 are a pair. The exterior member is configured.

  The positive electrode plate 11 constituting the power generation element 18 includes a positive electrode current collector 11a extending to the positive electrode tab 14, and positive electrode layers 11b and 11c formed on both main surfaces of a part of the positive electrode current collector 11a, respectively. Have As shown in FIG. 3, when the positive electrode plate 11, the separator 12 and the negative electrode plate 13 are laminated to form the power generation element 18, the positive electrode layers 11b and 11c are formed only on the portion of the positive electrode plate 11 that substantially overlaps the separator 12. Is formed.

The positive electrode side current collector 11a of the positive electrode plate 11 is made of an electrochemically stable metal foil such as an aluminum foil, an aluminum alloy foil, a copper foil, or a nickel foil. Moreover, the positive electrode layers 11b and 11c of the positive electrode plate 11 are formed of, for example, lithium composite oxides such as lithium nickelate (LiNiO ₂ ), lithium manganate (LiMnO ₂ ), or lithium cobaltate (LiCoO ₂ ), chalcogen ( S, Se, Te) A positive electrode side current collector obtained by mixing a positive electrode active material such as a compound, a conductive agent such as carbon black, an adhesive such as an aqueous dispersion of polytetrafluoroethylene, and a solvent. It is formed by applying to both main surfaces of a part of 11a, drying and rolling.

  The negative electrode plate 13 constituting the power generation element 18 includes a negative electrode side current collector 13a extending to the negative electrode tab 15, and negative electrode layers 13b and 13c formed on both main surfaces of a part of the negative electrode side current collector 13a, respectively. And have. As shown in FIG. 3, when the power generation element 18 is configured by laminating the positive electrode plate 11, the separator 12, and the negative electrode plate 13, the negative electrode layers 13 b and 13 c are formed only on portions of the negative electrode plate 13 that substantially overlap the separator 12. Is formed.

  The negative electrode side current collector 13a of the negative electrode plate 13 is made of an electrochemically stable metal foil such as nickel foil, copper foil, stainless steel foil, or iron foil. The negative electrode layers 13b and 13c of the negative electrode plate 13 are negative electrodes that occlude and release lithium ions of the positive electrode active material, such as amorphous carbon, non-graphitizable carbon, graphitizable carbon, or graphite. An active material is mixed with an aqueous dispersion of a styrene butadiene rubber resin powder as a precursor material of an organic fired body, dried and then pulverized to carry carbonized styrene butadiene rubber on the surface of carbon particles. A main material is formed by further mixing a binder such as an acrylic resin emulsion with the mixture, applying the mixture to both main surfaces of a part of the negative electrode current collector 13a, and drying and rolling.

  The separator 12 of the power generation element 18 prevents the short-circuit between the positive electrode plate 11 and the negative electrode plate 13 described above, and may have a function of holding an electrolyte. The separator 12 is a microporous film made of polyolefin such as polyethylene (PE) or polypropylene (PP), for example. When an overcurrent flows, the pores of the layer are blocked by the heat generation and the current is cut off. It also has a function.

  The power generation element 18 is formed by alternately stacking the positive electrode plates 11 and the negative electrode plates 13 with the separators 12 interposed therebetween. The three positive electrode plates 11 are connected to the positive electrode tab 14 made of metal foil via the positive electrode side current collector 11a, respectively, while the three negative electrode plates 13 are connected to the negative electrode side current collector 13a. In the same manner, the negative electrode tabs 15 made of metal foil are connected to each other.

  The power generation element 18 is accommodated and sealed in the upper exterior member 16 and the lower exterior member 17. Although not specifically illustrated, the upper exterior member 16 and the lower exterior member 17 of this example are both made of polyethylene, modified polyethylene, polypropylene, modified polypropylene, or ionomer from the inside to the outside of the flat battery 1. An inner layer composed of a resin film excellent in electrolytic solution resistance and heat-fusibility, an intermediate layer composed of a metal foil such as aluminum, and an electrical insulation such as a polyamide resin or a polyester resin And a three-layer structure composed of an outer layer made of a resin film having excellent properties.

  Therefore, both the upper exterior member 16 and the lower exterior member 17 are made of resin such as polyethylene, modified polyethylene, polypropylene, modified polypropylene, or ionomer on one surface (inner surface of the flat battery 1) of a metal foil such as aluminum foil. And the other surface (the outer surface of the flat battery 1) is laminated with a polyamide resin or a polyester resin, and is formed of a flexible material such as a resin-metal thin film laminate material.

  These exterior members 16, 17 enclose the power generation element 18, part of the positive electrode tab 14 and part of the negative electrode tab 15, so that the internal space formed by the exterior members 16, 17 contains an organic liquid solvent. While injecting a liquid electrolyte having a lithium salt such as lithium chlorate, lithium borofluoride or lithium hexafluorophosphate as a solute, the space formed by the exterior members 16 and 17 is sucked into a vacuum state, The outer peripheral edges of the members 16 and 17 are heat-sealed by hot pressing and sealed.

  Returning to FIG. 1, the ultrasonic sensor 2 includes a transmitter 21 and a receiver 22. The transmitter 21 transmits ultrasonic waves as vibration waves in the battery 1. The transmitted ultrasonic wave is reflected by the lower exterior member 17 where the ultrasonic sensor 2 is not provided, and is detected by the receiver 22. The receiver is a sensor that receives ultrasonic waves propagating in the battery.

  The attachment position of the ultrasonic sensor 2 will be described with reference to FIG. FIG. 4 is a plan view of the battery 1 to which the ultrasonic sensor 2 is attached. A transmitter 21 and a receiver 22 are arranged at diagonal positions on the surface of the upper exterior member 16, which is parallel to the laminated surface of members constituting the power generation element 18 such as the positive electrode plate 11. As will be described later, in this example, the state of the battery is estimated from the propagation time of the ultrasonic wave propagating in the battery 1. For this reason, in this example, the sensor 2 is arranged so that the propagation distance between the transmitter 21 and the receiver 22 is long, so that it is easy to detect a change in the propagation time according to the state of the battery. It is composed.

  The transmitter 21 is configured to cause ultrasonic waves to enter the battery 1 in an acute angle direction with respect to the surface of the exterior member 16. Thereby, the ultrasonic wave transmitted from the transmitter 21 reflects the lower exterior member 17 facing the exterior member 16 and propagates to the receiver 22.

  Returning to FIG. 1, the controller 3 includes an estimation unit 31 and a battery state estimation unit 32. The controller 3 is a control unit for estimating the state of the battery 1 based on the detection value of the ultrasonic sensor 2, and controls the ultrasonic sensor 2. The measurement unit 31 measures the hardness of the battery 1 from the detection value detected by the ultrasonic sensor 2. The battery state estimation unit 32 estimates the state of the battery 1 from the measurement value measured by the measurement unit 31.

  Here, the relationship between the hardness of the battery 1 and the state of the battery 1 will be described. FIG. 5 is a graph showing characteristics of the battery capacity with respect to the number of cycles in the battery 1. The number of cycles indicates the number of times of charging / discharging in which the fully charged battery is discharged to a predetermined capacity and charged to the fully charged state again. 5, N1 <N2 <N3 <N4, and the number of cycles from 0 to N1 is equal to the number of cycles from N1 to N2, N2 to N3 and N3 to N4. The number of cycles until is also equal.

  As the battery 1, a lithium ion secondary battery was used. And when the battery capacity after charging / discharging of each cycle was evaluated with respect to the full charge capacity of the battery in a state where the number of cycles was zero, characteristics as shown in FIG. 5 were obtained. Since the battery 1 is deteriorated by repeated charge and discharge, the battery capacity at the time of full charge decreases. Therefore, as shown in FIG. 5, the battery capacity at full charge decreased as the number of cycles increased.

Next, the hardness of the battery when charging and discharging are repeated will be described with reference to FIG. FIG. 6 is a graph showing the ratio of the battery hardness to the battery state. In FIG. 6, the hardness (h0) of the battery immediately after injecting the electrolyte into the battery 1 and the hardness (h1) of the battery when the electrolyte is completely impregnated in the pores of the separator 12 are shown. evaluated. Then, after completely impregnating the battery holes with the electrolyte, the charge / discharge cycle (N) is repeated, and the battery hardness (h2) when the battery capacity in FIG. 5 decreases to the specified value (Q _lim ). ) Was evaluated. The specified capacity value (Q _lim ) is a threshold value for indicating that the battery has deteriorated to a predetermined deterioration level.

  The horizontal axis of FIG. 6 shows the time-series state of the battery 1, “immediately after injection” indicates the state immediately after the electrolyte solution is injected, and “impregnation complete” indicates that the electrolyte solution is empty in the battery. The state in which the pores are completely impregnated is shown, and the “capacity specification value” shows a state in which the battery capacity reaches the specified value by repeating the charge / discharge cycle. Regarding the vertical axis in FIG. 6, the hardness of the battery is represented by the ratio of the hardness to the hardness (h0) immediately after injection, and H1 = h1 / h0 and H2 = h2 / h0.

Immediately after injecting the electrolytic solution, when the electrolytic solution was impregnated in the vacancies of the battery 1, the battery 1 became hard, so the hardness ratio (H) increased to H1 (> 1). When the ratio is H1, the battery 1 is not deteriorated and the number of cycles is zero. When the charge / discharge cycle is repeated, the hardness of the battery 1 increases as the battery deteriorates, and the ratio of the hardness of the battery 1 that has reached the specified capacity value (Q _lim ) is greater than H1 and H2 It became. Since the electrolyte solution of the battery 1 decreases as the battery 1 deteriorates, the battery 1 is cured. That is, the hardness of the battery 1 increases as the number of charge / discharge cycles increases. Further, as shown in FIG. 5, as the number of charge / discharge cycles increases, the capacity decreases and the battery 1 deteriorates. Therefore, as shown in FIG. 7, it can be confirmed that there is a correlation between the hardness of the battery and the deterioration state of the battery.

FIG. 7 is a graph showing the characteristics of the ratio of the battery hardness to the battery state. No deterioration is the state of the battery before use in a state where the number of cycles is zero. Q ₀ is the battery capacity at the time of full charge with no deterioration. The prescribed deterioration state indicates the state of the battery 1 that has deteriorated until the battery capacity reaches a prescribed value (Q _lim ) by repeating the charge / discharge cycle.

  As shown in FIG. 7, it was confirmed that there was a phase difference between the hardness of the battery and the deterioration of the battery. Therefore, if the hardness of the battery can be measured, the deterioration state of the battery 1 can be estimated from the relationship shown in FIG. However, it is difficult to directly measure the hardness of the battery 1 under the situation where the battery 1 is used in a vehicle or the like, but in this example, as described below, the vibration propagating in the battery 1 By measuring the wave characteristics, it was possible to indirectly measure the hardness of the battery.

  FIG. 8 is a schematic diagram for explaining the deterioration state of the battery 1 and the state of ultrasonic waves propagating in the battery 1. In FIG. 8, the initial state shows a state before the battery 1 is used, and the deterioration shows a state in which the battery 1 is used and deteriorated to some extent. At time (0), ultrasonic waves are transmitted from the transmitter 21. The ultrasonic wave transmitted at time (0) is attenuated by propagating in the battery 1, while the battery in the initial state is received by the receiver 22 at time (T1). On the other hand, in the battery in the deteriorated state, the receiver 22 receives the ultrasonic wave at time (T2), and the propagation time (T2) in the deteriorated state is shorter than the propagation time (T1) in the initial state. . That is, when the battery 1 deteriorates, the propagation time of the ultrasonic wave propagating through the battery 1 is shortened.

  Next, FIG. 9 shows the relationship between the number of cycles and the propagation time of ultrasonic waves. FIG. 9 is a graph showing the propagation time evaluated for each number of cycles. In the battery 1, when the number of cycles reached N1, N2, and N3, propagation times propagating through the battery 1 were evaluated. As shown in FIG. 9, it can be confirmed that the propagation time is shortened as the number of cycles increases. And

  And since the battery 1 hardens | cures with the increase in the number of cycles, it can confirm that there exists a correlation between propagation time and hardening of a battery. When the battery 1 is cured, the medium density in the battery 1 is increased. Therefore, as the battery 1 is cured, the propagation time of the vibration wave in the battery 1 is shortened and the propagation speed of the vibration wave is increased. Thereby, in this example, since the ultrasonic wave propagating through the battery can be detected using the ultrasonic sensor 2 and the propagation time of the detected ultrasonic wave can be measured, the propagation time indicates the hardness of the battery. Using it as an index, the state of deterioration of the battery 1 is estimated.

  Hereinafter, control of the controller 3 of this example will be described. The controller 3 controls the ultrasonic sensor 2 and transmits the ultrasonic wave 2 from the transmitter 21 into the battery. The controller 3 receives the ultrasonic waves transmitted from the transmitter 21 by the receiver 22. The measuring unit 31 measures the propagation time of the ultrasonic wave by measuring the reception time from the transmission time of the ultrasonic wave transmitted from the transmitter 21 and the ultrasonic wave reception timing corresponding to the detection value of the receiver 22. . Thereby, the measurement part 31 measures the propagation time of a vibration wave used as the parameter | index of the hardness of a battery.

  In addition, the measurement unit 31 measures the capacity reduction amount of the battery 1. The capacity reduction amount indicates a battery capacity that is reduced by using the battery with respect to the capacity when the battery 1 is not fully used. The measurement unit 31 measures the battery capacity when the battery 1 is fully charged, using detection values of a sensor (not shown) that measures the current and voltage of the battery 1. And since the full charge capacity of the battery 1 when not in use is recorded in the measurement part 31, the measurement part measures the capacity decrease amount of the battery 1 from the full charge capacity and the measured battery capacity.

The battery state estimation unit 32 estimates the state of the battery by comparing the propagation time (T _s ) measured by the measurement unit 31 with the degradation region determination time (T _a ) and the stop region determination time (T _b ). To do. The degradation area determination time (T _a ) is a threshold value for the propagation time indicating that the battery is excessively degraded, and is a value set according to the capacity reduction rate. The deteriorated area determination time (T _a ) is set so as to decrease as the capacity reduction rate increases.

As shown in FIG. 5, since the battery capacity is decreased by repeating the charging and discharging of the battery 1 and repeating the number of cycles, the capacity decrease amount increases. As the capacity reduction amount increases, the deterioration of the battery also progresses, so that the ultrasonic propagation time is shortened. At this time, the degree of deterioration of the battery with respect to the amount of capacity reduction varies depending on the battery usage history and usage environment. For example, when a large load is applied to the battery 1 due to driving of the vehicle, the deterioration rate of the battery 1 proceeds faster than the deterioration rate of the normal battery 1. A normal battery 1 is a battery 1 in which a load is applied to the battery 1 on an average, and the deterioration is averagely advanced. Therefore, when the measured propagation time (T _s ) is shorter than the deterioration region determination time (T _a ), the measured deterioration degree of the battery 1 is higher than the deterioration degree of a normal battery.

The stop region determination time (T _b ) is a propagation time threshold value indicating that the battery function is stopped, and is set to a value larger than the deterioration region determination threshold value (T _a ). When the function of the battery is stopped for any reason, the ultrasonic wave transmitted from the transmitter 21 does not propagate in the battery 1 or the propagation time is not increased even if the ultrasonic wave propagates to the receiver 22. It will be quite long. Therefore, when the measured propagation time (T _s ) is larger than the stop region determination threshold value (T _b ), the battery function is stopped for the measured battery 1.

The relationship among the capacity reduction amount, the propagation time, the degradation region determination threshold (T _a ), and the stop region determination time (T _b ) will be described with reference to FIG. FIG. 10 is a graph for explaining the degradation region and the stop region in the propagation time characteristic with respect to the capacity decrease amount. The deterioration area is an area indicating that deterioration is excessively advanced. The stop area is an area indicating that the battery function is stopped. Q _sL indicates the amount of decrease in the capacity of the normal battery 1 when the number of times the battery has been used reaches the limit number.

Regarding the degradation region determination threshold (T _a ), even in the case of a normal battery 1, the battery 1 is further deteriorated by repeating charging and discharging. Then, the propagation time indicated by the deteriorated region determination threshold (T _a ) decreases as the capacity reduction rate increases. Therefore, the degradation region determination threshold (T _a ) is set so as to decrease in proportion to the capacity decrease rate, as shown in the graph A.

On the other hand, the stop region determination time (T _b ) is a threshold value for determining the function stop of the battery 1 and is set to a constant value in order to correspond to a limit value when the battery 1 is used.

A range in which the propagation time is smaller than the degradation region determination threshold (T _a ) is set as the degradation region. In the deterioration region, the degree of deterioration increases as the propagation time (T _s ) decreases. Further, a range in which the propagation time is longer than the stop region determination time (T _b ) is a stop region.

In this example, around the deterioration area determination threshold (Ta), within a predetermined range (range between T a ₊ a T _a-), it is set as a normal region. The propagation time of the ultrasonic wave propagating through the battery 1 varies depending on the state of charge (SOC: State of Charge) of the battery 1 or the like. Therefore, in this example, the estimation accuracy of the battery state is increased by giving a predetermined width to the deterioration region determination threshold (T _a ).

That is, in this example, the deterioration determination region threshold (T _a− ) that is the lower limit value within a predetermined range centered on the deterioration region determination threshold (T _a ) is determined between the normal region and the deterioration determination region. It is set as a threshold value. When the propagation time is equal to or less than the deterioration determination region threshold (T _a− ), the battery state estimation unit 32 determines that the state of the battery 1 is excessively deteriorated. In addition, when the propagation time is longer than the deterioration determination region threshold (T _a− ) and less than the stop region determination time (T _b ), the battery state estimation unit 32 determines that the state of the battery 1 is normal. Judge that there is. When the propagation time is equal to or longer than the stop region determination time (T _b ), the battery state estimation unit 32 determines that the state of the battery 1 is a function stop state.

Hereinafter, the estimation control of the state of the battery 1 by the controller 3 will be described with reference to FIG. As described above, after the ultrasonic wave propagation time (T _s ) and the capacity reduction amount (Q _s ) are measured by the measurement unit 31, the battery state estimation unit 32 is based on the capacity reduction amount (Q _s ). A deteriorated area determination threshold (T _a ) is set.

As shown in FIG. 10, when the capacity reduction amount (Q _s ) measured by the measurement unit 31 is the capacity reduction amount (Q _s1 ), the battery state estimation unit 32 displays the capacity reduction amount (Q _The threshold value (T _a1 ) corresponding to _s1 ) is set to the deteriorated region determination threshold value (T _a ). Further, the battery state estimation unit 32 sets a predetermined area including the deteriorated area determination threshold (T _a1 ) as a normal area, and sets a deteriorated area determination threshold (T _a− ) as a lower limit value of the predetermined area. .

Then, the battery state estimation unit 32 includes a measurement value in the form of the propagation time measuring unit 31 _{(T s),} compared with the deterioration area determination threshold value _{(T a-),} the propagation time _{(T s)} and the stopping area determination Compare the time (T _b ).

When the propagation time (T _s ) is larger than the deterioration region determination threshold (T _a− ) and shorter than the stop region determination time (T _b ), the battery state estimation unit 32 changes the state of the battery 1 to normal deterioration. It is determined that it is in a state. On the other hand, when the propagation time (T _s ) is equal to or less than the deterioration region determination threshold value (T _a− ), the battery state determination unit 32 indicates that the state of the battery 1 is in the deterioration region and the battery 1 is excessively deteriorated. It is determined that it is in a state of being. Further, when the propagation time (T _s ) is equal to or longer than the stop region determination time (T _b ), the battery state determination unit 32 indicates that the state of the battery 1 is in the stop region and the battery 1 is in a function stop state. It is determined that there is.

  When it is determined that the state of the battery 1 is in a function stop state, the controller 3 alerts the user that the function is in a stop state by displaying a lamp or the like. Further, when it is determined that the state of the battery 1 is excessively deteriorated, or when it is determined that the state of the battery 1 is normal, the controller 3 does not display a lamp or the like. Alternatively, the determination result of the state of the battery 1 is notified.

  Next, the control procedure of the controller 3 will be described with reference to FIG. FIG. 11 is a flowchart showing a control procedure of the controller 3.

In step S <b> 1, the controller 3 controls the ultrasonic sensor 2, transmits an ultrasonic wave from the transmitter 21, and receives the ultrasonic wave by the receiver 22, thereby transmitting the ultrasonic wave propagating through the battery 1. To detect. In step S <b> 2, the measurement unit 31 measures the ultrasonic propagation time (T _s ) from the transmission time of the transmitter 21 and the reception time of the receiver 22. The measurement unit 31 measures the capacity decrease amount of the battery 1 from the detection values of the current and voltage sensors (step S3).

The battery state estimation unit 32 sets a deterioration region determination threshold (T _a− ) from the measured capacity reduction amount, and sets a normal region (step S4). In step S <b> 5, the battery state estimation unit 32 compares the measured propagation time (T _s ) with the degradation region determination threshold value (T _a− ).

If the propagation time (T _s ) is equal to or less than the degradation region determination threshold (T _a− ), the battery state estimation unit 32 determines in step S6 that the battery 1 is in an excessively deteriorated state, and this End the example control. Incidentally, the ultrasonic is not propagated in the cell 1, if not received by the receiver 22, it may be determined that the propagation time (T _s) becomes more stopping area determination threshold (T _b).

Returning to step S5, when the propagation time (T _s ) is larger than the degradation region determination threshold (T _a− ), the battery state estimation unit 32 determines the propagation time (T _s ) and the stop region determination threshold (T _b ). Are compared (step S7). If the propagation time (T _s ) is equal to or greater than the stop region determination threshold (T _b ), the battery state estimation unit 32 determines that the battery 1 is in a battery function stop in step S8. Incidentally, the ultrasonic is not propagated in the cell 1, if not received by the receiver 22, it may be determined that the propagation time (T _s) becomes more stopping area determination threshold (T _b). In step S9, the controller 3 displays a warning lamp and ends the control of this example.

Returning to step S7, if the propagation time (T _s ) is smaller than the stop region determination threshold (T _b ), in step S10, the battery state estimation unit 32 determines that the battery 1 is in a normal state. Then, the control of this example is finished.

  As described above, in this example, the ultrasonic sensor 2 detects ultrasonic waves propagating in the battery 1, the measurement unit 31 measures the hardness of the battery 1 from the detection value of the ultrasonic sensor 2, and the battery 1 Based on the relationship between the hardness of the battery 1 and the state of the battery 1, the state of the battery 1 is estimated from the measurement value of the measurement unit 31. Thereby, in this example, since the state of the battery 1 is estimated based on the current hardness of the battery 1, it is possible to estimate the deterioration state of the battery 1 and the function stop state of the battery 1 with high accuracy. it can.

  By the way, unlike this example, conventionally, the deterioration state of the battery 1 is detected with reference to basic data of the battery (initial data of the battery that has not deteriorated) recorded in advance in a memory or the like. It was. Therefore, when the usage environment and usage history of the battery 1 such as a vehicle are different, the actual deterioration state of the battery 1 is different from the detection result, and there is a problem that the detection accuracy of deterioration is low.

  Further, conventionally, there has been a problem that the detection accuracy of the battery state when the load is applied to the battery 1 during traveling of the vehicle is lower than the detection accuracy of the battery state at the time of charge / discharge.

  In the present invention, since the hardness of the battery is measured and the state of the battery is estimated based on the relationship between the hardness of the battery and the state of the battery, the measurement is performed regardless of the past battery usage status and usage history. From the battery state at the time, it is possible to estimate a state such as deterioration or function stop, and the state accuracy of the battery 1 can be improved. Moreover, since the hardness of the battery is measured in this example, the state of the battery 1 can be estimated even when the load is applied to the battery 1 during traveling of the vehicle or the like.

  Further, in this example, the ultrasonic wave propagation time in the battery 1 is measured as an index of the hardness of the battery 1 from the ultrasonic waves transmitted and received by the transmitter 21 and the receiver 22, and the state of the battery 1 is estimated. Thereby, since the hardness of the battery 1 can be grasped | ascertained, the estimation precision of the state of the battery 1 can be improved.

  Further, in this example, the transmitter 21 and the receiver 22 are respectively arranged at diagonal positions on the surface of the exterior member 16. Thereby, since the propagation distance of an ultrasonic wave can be lengthened, the measurement precision with respect to the sound speed change of an ultrasonic wave can be improved.

  In this example, the transmitter 21 is arranged so that ultrasonic waves are incident at an acute angle with respect to the surface of the exterior member 16. Thereby, since the propagation distance of an ultrasonic wave can be lengthened, the measurement precision with respect to the sound speed change of an ultrasonic wave can be improved.

Further, in this example, when the propagation time (T _s ) measured by the measurement unit 31 is smaller than the deterioration region determination threshold, it is estimated that the deterioration of the battery 1 is excessively advanced. Thereby, even when the deterioration state of the battery 1 progresses excessively due to the use history and use environment of the battery 1, the deterioration state of the battery 1 can be accurately estimated.

Further, in this example, when the propagation time (T _s ) measured by the measurement unit 31 is larger than the stop region determination threshold (Tb), it is estimated that the function of the battery 1 is stopped. Thereby, even when the function of the battery 1 is stopped for some reason, the state of the battery 1 can be accurately estimated.

  Moreover, in this example, the exterior members 16 and 17 of the battery 1 are formed of a laminate material that covers the power generation element. Thereby, the hardness of the battery 1 can be measured from the exterior by making the battery 1 into a laminate type (flat type). Moreover, since the battery 1 having a laminate structure is easier to detect a displacement (vibration) at a certain place than a battery having a can structure, it is possible to grasp a change in vibration characteristics. Further, since the thin and flexible laminate is used for the exterior members 16 and 17, the characteristics of the battery can be directly acquired.

  As a modification of the present invention, as shown in FIG. 12, a transmitter 21 may be provided on the upper exterior member 16 and a receiver 22 may be provided on the lower exterior member 17. FIG. 12 is a perspective view showing configurations of the battery 1 and the ultrasonic sensor 2 of the battery state determination device according to the modification of the present invention. The attachment position of the transmitter 21 on the upper exterior member 16 is provided at a position facing the attachment position of the receiver 22 on the lower exterior member 17. The ultrasonic wave transmitted from the transmitter 21 is transmitted in a direction perpendicular to the direction along the surface of the upper exterior member 16, propagates in the battery 1, and is received by the receiver 22.

  In this example, the ultrasonic sensor 2 is provided for the flat battery 1 and the state of the battery 1 is estimated. However, the ultrasonic sensor 2 is not limited to the flat battery 1, and may be, for example, a cylindrical battery. And the state of the battery 1 may be estimated in the same manner as described above. FIG. 14 is a perspective view of the transmitter 21, and FIG. 15 is a cross-sectional view taken along line BB of the drawing. As shown in FIGS. 14 and 15, the surface of the transmitter 2 that comes into contact with the cylindrical battery 1 (the surface on which ultrasonic waves are transmitted) is formed into a curved surface so as to be along the side surface of the cylindrical battery. Is formed. Similarly, the receiving surface of the receiver 22 is formed into a curved surface along the side surface of the cylindrical battery. Thereby, the battery state estimation apparatus of this example can be applied to the circular battery 1.

  In this example, the deterioration degree of the battery 1 may be estimated according to the propagation time measured by the measurement unit 31. As shown in FIG. 6, the hardness of the battery 1 and the state of deterioration of the battery are correlated, and from the relationship of FIG. 6, the degree of deterioration of the battery increases as the hardness of the battery increases. In this example, the propagation time is used as an index of the hardness of the battery, and there is a correlation between the propagation time and the hardness of the battery.

  Therefore, the battery state estimation unit 32 records in advance a map indicating the relationship between the propagation time corresponding to the hardness of the battery 1 and the degree of deterioration of the battery 1. Then, the battery state estimation unit 32 estimates the degree of deterioration corresponding to the map as the deterioration state of the battery 1 by referring to the map from the propagation time measured by the measurement unit 31. Thereby, this example can estimate the deterioration state of the battery 1 using the map of propagation time and deterioration degree.

  In this example, the propagation time is used as an index of the hardness of the battery 1. However, the propagation speed may be calculated from the propagation time measured by the measurement unit 31, and the state of the battery 1 may be estimated from the propagation speed.

In this example, the degradation region determination threshold (T _a− ) is used as the determination threshold for the normal region and the degradation region. However, the degradation region determination threshold (T _{a +} ) or the degradation region determination threshold (T _a ) is used. May be.

  The ultrasonic sensor 2 corresponds to the “first sensor” of the present invention, the measurement unit 31 transmits to the “measurement unit” of the present invention, and the battery state estimation unit 32 transmits to the “battery state estimation unit” of the present invention. The device 21 corresponds to “transmission means”, and the receiver 22 corresponds to “reception means”.

<< Second Embodiment >>
FIG. 15 is a block diagram of a battery state estimation device according to another embodiment of the invention. In this example, the sensor configuration and a part of the control of the controller 3 are different from the first embodiment described above. Since the configuration other than this is the same as that of the first embodiment described above, the description thereof is incorporated as appropriate.

  The battery state estimation device includes a battery 1, a controller 3, a pickup sensor 4, a mounting plate 51, and support members 52 and 53. The pickup sensor 4 is a sensor for detecting vibrations of the battery 1 and the mounting plate 51. The pickup sensor 4 includes a pickup sensor 41 provided on the surface of the battery 1 and a pickup sensor 42 provided on the surface of the attachment plate 51.

  The battery 1 is provided on the vehicle body 4 via a mounting plate 51. The attachment plate 51 is a plate-like member for attaching the battery 1 to the vehicle body 4, and is formed of a material having higher rigidity than the battery 1 and the vehicle body 4. The mounting plate 51 is fixed to the vehicle body 4 by a support member 52. The battery 1 is fixed to the mounting plate 51 by a support member 53. The support members 52 and 53 fasten the battery 1, the mounting plate 51, and the vehicle with screws or the like while leaving a space between the battery 1 and the mounting plate 51 and between the mounting plate 51 and the vehicle body 4. It is a member. With this configuration, a constant excitation force based on the vibration of the vehicle 1 can be applied to the fastening portion between the battery 1 and the support member 53 regardless of the rigidity of the vehicle body 4.

  The mounting position of the pickup sensor 41 on the surface of the battery 1 will be described. If K is the spring constant due to the hardness of the battery 1, P is the soaking force applied to the battery 1, and δ is the displacement of the battery 1, the relational expression of K = P / δ between K, P and δ. Is established.

  The mounting position of the pickup sensor 41 is mounted so as to be as far as possible from the mounting plate 51. Thereby, a large displacement can be obtained when an excitation force is applied to the battery 1.

  When the battery 1 and the mounting plate 51 vibrate due to the road noise of the vehicle body 4 or the vibration of the engine 10, the pickup sensors 41 and 42 detect the vibration acceleration of the battery 1 and the mounting plate 51 due to the vibration, and the detected value is And output to the controller 3 by an electrical signal. Thereby, the pickup sensors 41 and 42 detect vibration waves of the battery 1 and the mounting plate 51 due to an external excitation force, and output them to the controller 3.

  That is, in the first embodiment, a vibration wave is generated in the battery 1 by the transmitter 21 of the ultrasonic sensor 2, but in this example, the transmitter 1 of the battery 1 is used without using a transmitter such as the transmitter 21. The configuration is such that vibration waves in the battery 1 are detected using externally generated vibrations.

  The measurement unit 31 measures the frequency characteristic of the vibration of the battery 1 by taking the difference between the detection value of the pickup sensor 41 and the detection value of the pickup sensor 42. In this example, the vibration frequency of the vibration wave of the battery 1 is used as an index representing the hardness of the battery.

  Here, the characteristics of the vibration frequency of the battery 1 will be described. FIG. 16 is a graph showing the inertance characteristics with respect to the vibration frequency. The inertance represents the ratio between the acceleration and the excitation force at the measurement point of the pickup sensor 4.

  Graph a shows the characteristics in a state where the number of cycles is small and the battery 1 is hardly deteriorated. The grab b shows the characteristics of the state of the battery 1 in which the number of cycles is larger and the deterioration has progressed to some extent as compared with the graph a. Graph c shows characteristics in a state in which the number of cycles is further increased and deterioration of battery 1 is most advanced as compared with graphs a and b.

  Further, in the characteristics of the graphs a, b, and c, the highest inertance frequency, fa, fb, and fc, are the resonance frequencies of the vibration wave of the battery 1. As shown in the graphs a to c, when the deterioration of the battery 1 progresses, the frequency characteristic of the vibration wave of the battery 1 changes and the resonance frequency increases (fa <fb <fc).

Table 1 shows data showing the relationship between the deterioration state and the resonance frequency in an actual battery showing a normal deterioration tendency. The battery deterioration amount indicates a reduction amount of the discharge capacity as a percentage. The discharge capacity was the capacity of the battery discharged until the battery 1 was completely discharged (SOC was 0%).

  From Table 1, it can be confirmed that the higher the deterioration degree of the battery 1, the higher the resonance frequency.

  As described in the first embodiment, there is a correlation between the deterioration of the battery 1 and the hardness of the battery. Therefore, in this example, the deterioration state of the battery is estimated by using the resonance frequency of the vibration wave in the battery 1 as an index representing the hardness of the battery.

  Next, control of the controller 3 will be described. First, the controller 3 controls the pickup sensor 4 to detect the acceleration of vibration of the battery 1 and the acceleration of vibration of the mounting plate 51. The measurement unit 31 takes the difference between the detection values of the pickup sensors 41 and 42 and measures the frequency characteristics of the vibration wave of the battery 1. And the measurement part 31 specifies the frequency with the highest output value as a resonant frequency from the measured frequency characteristic.

  The measuring unit 31 measures the battery characteristics of the battery 1 from the voltage connected to the battery 1 and the detection value of the current sensor 6. In this example, the capacity (discharge capacity) that can be discharged from the battery 1 is calculated as the electrical deterioration characteristics of the battery 1 and corresponds to the battery deterioration amount shown in Table 1. The calculation of the discharge capacity may be performed, for example, by integrating the discharge current value from the detection value of the current sensor. And the measurement part 31 calculates the measured discharge capacity with respect to the discharge capacity of the battery 1 of an unused state as a decreasing rate of discharge capacity. As the battery characteristics, rate characteristics and direct current resistance (DCR) may be used in addition to the discharge capacity.

  The battery state estimation unit 32 records in advance a characteristic indicating a correspondence relationship between the resonance frequency of the vibration wave and the discharge capacity deterioration rate in the battery 1 showing a normal deterioration tendency as a deterioration characteristic of the battery 1 in a normal state on a map. ing. As described above, when the deterioration of the battery 1 proceeds normally, the resonance frequency gradually increases, and the discharge capacity reduction rate gradually increases.

  FIG. 17 shows the relationship between the reduction rate of the discharge capacity and the resonance frequency. FIG. 17 is a graph showing the characteristics of the reduction rate of the discharge capacity with respect to the resonance frequency. Graph d is a characteristic of battery 1 showing a normal deterioration tendency. When the battery 1 to be measured has deteriorated normally, the resonance frequency and the discharge capacity deterioration rate measured by the measurement unit 31 have values on the graph d or values close to the graph d. Become.

  Since the hardness of the battery 1 changes according to the state of charge (SOC) of the battery 1, the characteristics (characteristics of the graph d) of the battery 1 having a normal deterioration tendency also change. Therefore, in this example, the correspondence relationship between the resonance frequency of the vibration wave and the discharge deterioration amount according to the SOC is recorded on a map. That is, as shown in FIG. 17, the characteristics of a battery having a normal deterioration tendency are indicated by a band-shaped region D centered on the graph d.

  The battery state estimation unit 32 records the range indicated by the region D in FIG. 17 as a normal region of the battery 1 in advance using a map. Then, the battery state estimation unit 32 determines whether or not the resonance frequency of the vibration wave and the discharge capacity reduction rate measured by the measurement unit 31 are included in the normal region.

  When the resonance frequency of the vibration wave and the discharge capacity decrease rate measured by the measurement unit 31 are included in the normal region, the battery state estimation unit 32 determines that the state of the battery 1 is normal. On the other hand, when the resonance frequency of the vibration wave and the discharge capacity decrease rate measured by the measurement unit 31 are outside the normal region, the battery state estimation unit 32 determines that the battery function of the battery 1 is stopped. .

The above determination control will be described with reference to FIG. 17. For example, in Samples 1 and 2 (S ₁ and S _{2 in} FIG. 17), the resonance frequency and discharge capacity reduction rate of the vibration wave measured by the measurement unit 31 are shown. Since it is in the normal region D, the battery state estimation unit 32 determines that the battery 1 is normal.

On the other hand, in sample 3 (S _{3 in} FIG. 17), the measured decrease rate of the discharge capacity is higher than the decrease rate of the discharge capacity of the normal battery 1 with respect to the measured resonance frequency. The measured value 31 is outside the normal region D. In sample 4 (S _{4 in} FIG. 17), the measured decrease rate of the discharge capacity is lower than the decrease rate of the discharge capacity of the normal battery 1 with respect to the measured resonance frequency. The measured value 31 is outside the normal region D. The battery state estimation unit 32 determines that the functions of the battery 1 are stopped in the samples 3 and 4.

  In addition, when the resonance frequency was measured for the actual battery 1, in the battery 1 showing a normal deterioration tendency, the resonance frequency was 181 Hz when the battery deterioration amount (2.2%). On the other hand, in the battery showing an excessive deterioration tendency, the resonance frequency was 183 Hz at the same battery deterioration amount (2.2%). As a result, it can be confirmed that the resonance frequency becomes higher as the deterioration degree progresses than the normal deterioration degree. Therefore, in this example, the characteristics of the battery are compared with the characteristics of the normal battery as described above. Thus, it can be seen that the state of the battery can be estimated.

  Next, the control procedure of the controller 3 will be described with reference to FIG. FIG. 18 is a flowchart showing the control procedure of the controller 3.

  In step S <b> 21, the controller 3 controls the pickup sensor 4 to detect a vibration wave propagating through the battery 1. In step S <b> 22, the measurement unit 31 measures the frequency characteristic of the vibration wave in the battery 1 from the detection value of the pickup sensor 4. In step S23, the measurement unit 31 measures the resonance frequency from the measured frequency characteristics.

  In step S <b> 24, measurement unit 31 measures the discharge capacity of battery 1 from the detected value of current and voltage sensor 6. In step S25, the battery state estimation unit 32 determines whether or not the characteristics of the battery 1 indicated by the measured values of the resonance frequency and the discharge capacity measured in steps S23 and S24 are in the normal region. When the measured characteristics of the battery 1 are not within the normal region, the battery state estimation unit 32 determines that the battery function of the battery 1 is stopped. In step S27, the controller 3 displays a warning lamp (not shown) and ends the control of this example.

  Returning to step S25, if the measured characteristics of the battery 1 are within the normal range, the battery state estimation unit 32 determines that the battery 1 is normal (step S28), and ends the control of this example. To do.

  As described above, in this example, the pickup sensor 4 detects a vibration wave propagating in the battery 1, the measurement unit 31 measures the hardness of the battery 1 from the detection value of the pickup sensor 4, and the hardness of the battery 1 is determined. Based on the relationship between the state of the battery 1 and the state of the battery 1, the state of the battery 1 is estimated from the measurement value of the measurement unit 31. Thereby, in this example, since the state of the battery 1 is estimated based on the current hardness of the battery 1, it is possible to estimate the deterioration state of the battery 1 and the function stop state of the battery 1 with high accuracy. it can.

  In this example, the vibration frequency of the vibration wave is measured as an index representing the hardness of the battery 1. Thereby, since the hardness of the battery 1 can be grasped | ascertained, the estimation precision of the state of the battery 1 can be improved.

  Moreover, this example has a pickup sensor 4 as a sensor for measuring the hardness of the battery. Thereby, cost can be held down.

  In this example, the resonance frequency of the battery 1 is measured from the characteristics of the vibration frequency of the battery 1, and the state of the battery 1 is estimated from the resonance frequency. Thereby, since the hardness of the battery 1 can be grasped | ascertained, the estimation precision of the state of the battery 1 can be improved. Further, by making the resonance frequency a characteristic of the vibration frequency, it can be used as a substitute characteristic of the usage history.

  Further, in this example, the characteristics of the battery 1 are measured from the detected values of the current and voltage sensors, and the measured characteristics are compared with the battery characteristics indicating the deterioration characteristics of the battery under normal conditions. 1 state is estimated. Depending on the usage history (use period, use condition) of the battery 1, the hardness of the battery 1 changes and the battery characteristics also change. The relationship between the battery hardness and the battery characteristics with respect to the battery usage history is unambiguous. Therefore, the state of the battery 1 can be estimated without grasping the usage history of the battery 1 by comparing the battery characteristics and the vibration frequency characteristics indicating the battery hardness at a certain point in time. In addition, the system can be simplified.

  In addition, in this example, when the battery characteristics measured by the measurement unit 31 indicate characteristics outside the normal region D including the normal battery deterioration characteristics, the function of the battery 1 is stopped. presume. Thereby, since the state of the battery 1 can be estimated corresponding to the difference in hardness due to the SOC of the battery 1, the estimation accuracy of the battery 1 can be increased.

  In this example, the degree of deterioration of the battery 1 may be estimated according to the vibration frequency of the vibration wave measured by the measurement unit 31. As shown in FIG. 6 of the first embodiment, the hardness of the battery 1 and the state of deterioration of the battery have a correlation, and from the relationship of FIG. 6, the degree of deterioration of the battery increases as the hardness of the battery increases. In this example, the vibration frequency is used as an index of the hardness of the battery, and there is a correlation between the vibration frequency and the hardness of the battery.

  Therefore, the battery state estimation unit 32 records in advance a map indicating the relationship between the vibration frequency corresponding to the hardness of the battery 1 and the degree of deterioration of the battery 1. Then, the battery state estimation unit 32 estimates the corresponding deterioration degree on the map as the deterioration state of the battery 1 by referring to the map from the vibration frequency measured by the measurement unit 31. Thereby, this example can estimate the deterioration state of the battery 1 using the map of a vibration frequency and a deterioration degree.

  In this example, the resonance frequency is used as an index of the hardness of the battery. However, in specifying the frequency of the vibration wave of the battery 1, a frequency other than the resonance frequency may be used.

  In this example, the pickup sensor 4 is used as a sensor for detecting the vibration wave of the battery 1, but another sensor may be used.

  The pickup sensor 4 corresponds to the “first sensor” of the present invention, and the current / voltage sensor 6 corresponds to the “second sensor” of the present invention.

<< Third Embodiment >>
A battery state estimation apparatus according to another embodiment of the invention will be described. This example is different from the second embodiment described above in that coherence is used as an index representing the hardness of the battery 1. Since the configuration other than this is the same as that of the second embodiment described above, the description thereof is incorporated as appropriate.

  First, the coherence characteristics of the battery 1 will be described. FIG. 19 is a graph showing the coherence characteristic with respect to the frequency of the vibration wave of the battery 1. The coherence indicates the coincidence rate of the frequency characteristics of the vibration wave measured a plurality of times, and the coherence with respect to the frequency becomes 1 when the frequency characteristics of the plurality of times completely coincide.

  Graph a shows the characteristics in a state where the number of cycles is small and the battery 1 is hardly deteriorated. The grab b shows the characteristics of the state of the battery 1 in which the number of cycles is larger and the deterioration has progressed to some extent as compared with the graph a. Graph c shows characteristics in a state in which the number of cycles is further increased and deterioration of battery 1 is most advanced as compared with graphs a and b. fa, fb, and fc indicate frequencies when the coherence is lower than a predetermined value (L <1) in the predetermined frequency bands of the graphs a to c.

  As shown in FIG. 19, it can be seen that as the number of cycles of the battery 1 increases, the coherence becomes high even on the high frequency side, and the frequency at which the coherence becomes lower than L increases.

Table 2 shows data indicating the relationship between the deterioration state and the resonance frequency in an actual battery exhibiting a normal deterioration tendency. The battery deterioration amount indicates the rate of decrease in discharge capacity as a percentage. The discharge capacity was the capacity of the battery discharged until the battery 1 was completely discharged (SOC was 0%). The discharge capacity is the same as the discharge capacity of the second embodiment. In Table 2, the resonance frequency indicates the frequency when the coherence becomes L.

  From this result, it can be confirmed that the higher the degree of deterioration of the battery 1, the higher the frequency at which the coherence is higher.

  As described in the first embodiment, when the battery 1 is further deteriorated, the electrolytic solution is decomposed and consumed, and the amount of the electrolytic solution is reduced. Generally, when a liquid is present in a certain object, the transfer characteristic in the object becomes irregular. Therefore, when the amount of electrolyte is large, the transfer characteristics become unstable, and when coherence is taken, the coherence in the high frequency band is low, and the frequency at which the coherence is lower than L appears in the low frequency band. Then, as the amount of the electrolytic solution decreases, the transmission characteristics become stable, so the coherence on the high frequency side also increases, and the frequency at which the coherence becomes lower than L gradually shifts to the high frequency side.

  As shown in FIG. 19, when the battery 1 is hardly deteriorated, there is a frequency (fa) at which coherence is lower than L, as shown in the graph a. When the battery 1 is further deteriorated, as shown in the graph b, the coherence on the high frequency side becomes higher, and the frequency (fb) at which the coherence becomes lower than L becomes higher than fa. As the deterioration further proceeds, as shown in the graph c, the coherence on the high frequency side further increases, and the frequency (fc) at which the coherence becomes lower than L becomes higher than fb.

  And since the fall of electrolyte solution will increase the hardness of the battery 1, it turns out that there is a correlation between the coherence of the vibration wave and the hardness of the battery 1. Therefore, in this example, the deterioration state of the battery is estimated by using the coherence of the vibration wave in the battery 1 as an index representing the hardness of the battery.

  Next, control of the controller 3 will be described. First, the controller 3 controls the pickup sensor 4 to measure the frequency characteristics of the vibration wave of the battery 1. And the measurement part 31 synthesize | combines the several frequency characteristic measured within predetermined time, and measures a synthetic | combination characteristic. This synthesis characteristic is a coherence characteristic.

  The measuring unit 31 measures the battery characteristics of the battery 1 from the voltage connected to the battery 1 and the detection value of the current sensor 6. For the battery characteristics, the rate of decrease of the discharge capacity may be used as in the second embodiment.

  The battery state estimation unit 32 records in advance a characteristic indicating a correspondence relationship between the coherence of the vibration wave and the discharge capacity reduction rate in the battery 1 exhibiting a normal deterioration tendency as a deterioration characteristic of the battery 1 in a normal state with a map. Yes. The coherence characteristic may be a characteristic of the discharge deterioration amount with respect to a frequency (corresponding to fa, fb, and fc in FIG. 19) at which the coherence is lower than L.

  In addition, since the hardness of the battery 1 changes in accordance with the state of charge (SOC) of the battery 1, the battery state estimation unit 32 is within a predetermined range with the above characteristics of the battery 1 showing a normal deterioration tendency as the center. Are recorded in advance as the characteristics of the normal region. Then, the battery state estimation unit 32 determines whether or not the coherence characteristic of the vibration wave measured by the measurement unit 31 is included in the normal region.

  When the coherence characteristic of the vibration wave measured by the measurement unit 31 is included in the normal region, the battery state estimation unit 32 determines that the state of the battery 1 is normal. On the other hand, when the coherence characteristic of the vibration wave measured by the measurement unit 31 is outside the normal region, the battery state estimation unit 32 determines that the battery function of the battery 1 is stopped.

  Next, the control procedure of the controller 3 will be described with reference to FIG. FIG. 20 is a flowchart showing a control procedure of the controller 3. Since the control processing of steps S31 to 32 and S34 to 38 is the same as the control processing of steps S21 to 22 and S24 to 38 of FIG. 18 of the second embodiment, the description thereof is omitted.

  After step S32, the measurement unit 31 combines a plurality of frequency characteristics measured within a predetermined time, and measures the coherence characteristic with respect to the frequency. Then, the frequency at which the coherence is lower than L (resonance frequency) is measured from the measurement unit 31 concerned characteristics (step S33), and the process proceeds to step S34.

  As described above, in this example, a combined characteristic obtained by combining a plurality of frequency characteristics of vibration waves is measured, and the state of the battery is estimated from the combined characteristic. When the amount of the electrolytic solution is large, the frequency with high coherence is a frequency on the low frequency side, and when the amount of the electrolytic solution is small, the frequency on the high frequency side is also a frequency with high coherence. And if a battery is used and it deteriorates, electrolyte solution will reduce and the battery 1 will become hard. Therefore, in this example, since the hardness of the battery 1 can be grasped from the coherence, the estimation accuracy of the state of the battery 1 can be increased. Moreover, it can use as a substitute characteristic of a use history by using a coherence characteristic.

DESCRIPTION OF SYMBOLS 1 ... Battery 11 ... Positive electrode plate 11a ... Positive electrode side collector 11b, 11c ... Positive electrode layer 12 ... Separator 13 ... Negative electrode plate 13a ... Negative electrode side collector 13b, 13c ... Negative electrode layer 14 ... Positive electrode tab (electrode tab)
15 ... Negative electrode tab (electrode tab)
DESCRIPTION OF SYMBOLS 16 ... Upper exterior member 17 ... Lower exterior member 18 ... Electric power generation element 2 ... Ultrasonic sensor 21 ... Transmitter 22 ... Receiver 3 ... Controller 31 ... Measurement part 32 ... Battery state estimation part 4 ... Car body 6 ... Current and voltage sensor 51 ... Mounting plates 52, 53 ... Support members

Claims (23)

A battery in which a power generation element is enclosed inside an exterior member;
A first sensor disposed on a surface of the exterior member and detecting a vibration wave propagating in the battery;
Measuring means for measuring the hardness of the battery from the detection value of the first sensor;
A battery state estimation device comprising: a battery state estimation unit that estimates a state of the battery from a measurement value of the measurement unit based on a relationship between the hardness of the battery and the state of the battery. The first sensor is
Transmitting means for transmitting ultrasonic waves as the vibration wave in the battery;
Receiving means for receiving the ultrasonic wave propagated in the battery,
The measuring means includes
2. The battery according to claim 1, wherein a propagation time of the ultrasonic wave in the battery is measured as an index representing hardness of the battery from the ultrasonic wave transmitted and received by the transmitting unit and the receiving unit. State estimation device. A first map showing a relationship between the propagation time corresponding to the hardness of the battery and a deterioration state of the battery representing the state of the battery;
The battery state estimation device according to claim 2, wherein the first battery state estimation means estimates the deterioration state from the propagation time measured by the measurement means with reference to the first map. 4. The battery state estimation apparatus according to claim 2, wherein the transmitting unit and the receiving unit are respectively arranged at diagonal positions on the surface of the battery. 5. The battery state estimation apparatus according to claim 2, wherein the transmission unit makes the ultrasonic wave incident in an acute angle direction with respect to a surface of the battery. The battery state estimating means includes
6. The battery is estimated to be excessively deteriorated when the propagation time measured by the measuring unit is smaller than a preset first propagation time threshold value. The battery state estimation device according to any one of the above. The battery state estimating means includes
The electric function of the battery is estimated to be stopped when the propagation time measured by the measuring means is larger than a preset second propagation time threshold value. The battery state estimation device according to any one of the above. The battery according to claim 1, wherein the measurement unit measures a vibration frequency of a vibration wave detected by the first sensor as an index representing the hardness of the battery. State estimation device. A second map showing a relationship between the characteristics of the vibration frequency corresponding to the hardness of the battery and the deterioration state of the battery representing the state of the battery;
9. The battery state estimation device according to claim 8, wherein the battery state estimation unit estimates the deterioration state from the vibration frequency measured by the measurement unit with reference to the second map. The battery state estimation apparatus according to claim 8, wherein the first sensor includes a pickup sensor. The measuring means measures the resonance frequency of the battery from the characteristics of the vibration frequency,
The battery state estimation device according to any one of claims 8 to 10, wherein the battery state estimation unit estimates the state of the battery from the resonance frequency. The measuring means measures a composite characteristic obtained by combining a plurality of frequency characteristics of vibration waves,
The battery state estimation device according to any one of claims 8 to 10, wherein the battery state estimation unit estimates the state of the battery from the combined characteristic. A second sensor for detecting the voltage or current of the battery;
The measuring means measures a first battery characteristic indicating a characteristic of the battery with respect to the vibration frequency from a detection value of the second sensor;
The battery state estimating means includes
The characteristics of the battery at normal time with respect to the vibration frequency are recorded in advance as the second battery characteristics,
The battery state estimation device according to any one of claims 8 to 12, wherein the first battery characteristic is compared with the second battery characteristic, and the state of the battery is estimated from the comparison result. . The battery state estimating means includes
The function of the battery according to claim 13, wherein when the first battery characteristic indicates a characteristic outside a predetermined range including the second battery characteristic, the function of the battery is estimated to be stopped. Battery state estimation device. The battery state estimation device according to claim 1, wherein the exterior member is a laminate material that covers the power generation element. A vehicle comprising the battery state estimation device according to any one of claims 1 to 15. In the battery state estimation method for estimating the state of the battery in which the power generation element is sealed inside the exterior member,
A detection step of detecting a vibration wave propagating in the battery;
A measurement step of measuring the hardness of the battery from the detection value detected in the detection step;
A battery state estimation method comprising: an estimation step of estimating the state of the battery from the measurement value measured in the measurement step based on a relationship between the hardness of the battery and the state of the battery. The detecting step includes
Transmitting an ultrasonic wave as the vibration wave in the battery;
Receiving the ultrasonic wave propagated in the battery,
The battery state estimation method according to claim 17, wherein the measuring step measures the propagation time of the ultrasonic wave in the battery as an index representing the hardness of the battery. The estimation step includes
Referring to the first map showing the relationship between the propagation time corresponding to the hardness of the battery and the deterioration state of the battery representing the state of the battery, the deterioration state from the propagation time measured by the measurement step The battery state estimation method according to claim 18, wherein: The measuring step includes
The battery state estimation device according to any one of claims 17 to 19, wherein a vibration frequency of the vibration wave is measured as an index representing the hardness of the battery. The estimation step includes
With reference to a second map showing the relationship between the characteristics of the vibration frequency corresponding to the hardness of the battery and the deterioration state of the battery representing the state of the battery, the vibration frequency measured by the measuring means is The battery state estimation method according to claim 20, wherein the deterioration state is estimated. The detecting step includes detecting a voltage or current of the battery;
The measuring step measures a first battery characteristic indicating a characteristic of the battery with respect to the vibration frequency from the current value or the voltage value detected in the detecting step,
The estimation step includes
21. The second battery characteristic, which is a characteristic of the battery in a normal state with respect to the vibration frequency, is compared with the first battery characteristic, and the state of the battery is estimated from the comparison result. 22. The battery state estimation method according to 21. In the estimating step, when the first battery characteristic indicates a characteristic outside a predetermined allowable range including the second battery characteristic, it is estimated that the electric function of the battery is stopped. The battery state estimation method according to claim 22.

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