Battery internal state detection device and battery internal state detection method

Abstract

To provide a battery internal state detection device and a battery internal state detection method that can precisely detect the internal state of a battery.SOLUTION: A battery internal state detection device 100 is configured to detect the internal state of a battery 200 which has a lamination structure of an electrode mixture layer 24 including an electrode active substance and a current collector 23, and comprises an acoustic radiation body 11a which is provided to a negative electrode-side tab lead 29a and radiates an acoustic signal, an acoustic reception body 11b which is provided to a positive electrode-side tab lead 29b and receives the acoustic signal as a measurement acoustic signal, and a determination part 12 which determines the internal state of the battery 200 based upon the measurement acoustic signal.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a battery internal state detection device and a battery internal state detection method.

Background Art

[0002] The battery management system described in Patent Document 1 has an acoustic radiator and an acoustic receiver provided on the outer wall of the battery, respectively. The acoustic receiver receives the acoustic signal radiated by the acoustic radiator, and the battery management system detects an abnormality based on the acoustic signal received by the acoustic receiver.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, since the acoustic radiator and the acoustic receiver of the battery management system described in Patent Document 1 are provided on the outer wall of the battery, the acoustic signal is likely to attenuate before being received by the acoustic receiver, and there is a risk that the detection accuracy of the internal state of the battery will be lowered.

[0005] The problem to be solved by the present invention is to provide a battery internal state detection device and a battery internal state detection method capable of accurately detecting the internal state of a battery.

Means for Solving the Problems

[0006] The present invention solves the above problems by providing a first electrode terminal portion where an acoustic radiator is electrically connected to a current collector or an electroconductive member electrically connected to the first electrode terminal portion, and an acoustic receiver is provided at a second electrode terminal portion different from the first electrode terminal portion and electrically connected to the current collector or an electroconductive member electrically connected to the second electrode terminal portion.

Effects of the Invention

[0007] According to the present invention, there is an effect that the internal state of the battery can be accurately detected.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described based on the drawings. 《First Embodiment》 As shown in FIG. 1, the battery internal state detection device 100 according to this embodiment detects the internal state of the battery 200. The battery internal state detection device 100 includes an acoustic radiator 11a, an acoustic receiver 11b, a determination unit 12, and a storage unit 13. The acoustic radiator 11a and the acoustic receiver 11b are attached to the battery 200. The acoustic radiator 11a is, for example, a piezoelectric acoustic radiator and emits an acoustic signal having a predetermined frequency and acoustic intensity (amplitude). The acoustic receiver 11b is, for example, a piezoelectric acoustic receiver and receives the acoustic signal. Also, the determination unit 12 and the storage unit 13 can exchange information with each other. The determination unit 12 and the storage unit 13 may be provided in one device, or may be two devices connected to each other by wire or wirelessly. Also, the determination unit 12 is connected to the acoustic radiator 11a and the acoustic receiver 11b by wire or wirelessly.

[0010] As shown in FIG. 1, the battery 200 has a power storage element 21 sealed inside a battery exterior portion 22 such as a laminate film. The power storage element 21 has a laminated structure of a current collector 23 and an electrode mixture layer 24 containing an electrode active material. Specifically, in the example shown in FIG. 1, the power storage element 21 has a plurality of negative electrodes 25 and a plurality of positive electrodes 26 alternately arranged along the lamination direction L. The negative electrode 25 has a negative electrode side current collector 23a and a negative electrode side electrode mixture layer 24a provided on both or one side surface of the negative electrode side current collector 23a. The positive electrode 26 has a positive electrode side current collector 23b and a positive electrode side electrode mixture layer 24b provided on both or one side surface of the positive electrode side current collector 23b. That is, the current collector 23 (negative electrode side current collector 23a and positive electrode side current collector 23b) and the electrode mixture layer 24 (negative electrode side electrode mixture layer 24a and positive electrode side electrode mixture layer 24b) are laminated along the lamination direction L. A separator 27 is provided between the negative electrode side electrode mixture layer 24a and the positive electrode side electrode mixture layer 24b.

[0011] From the battery exterior portion 22 of the battery 200, a negative tab lead 29a connected to the negative electrode current collector 23a and a positive tab lead 29b connected to the positive electrode current collector 23b are led out. The negative tab lead 29a constitutes a first electrode terminal portion electrically connected to the current collector 23. Further, the positive tab lead 29b constitutes a second electrode terminal portion electrically connected to the current collector 23. Further, an acoustic radiator 11a is attached to the negative tab lead 29a which is the first electrode terminal portion. Further, an acoustic receiver 11b is attached to the positive tab lead 29b which is the second electrode terminal portion. Note that the acoustic receiver 11b may be attached to the negative tab lead 29a and the acoustic radiator 11a may be attached to the positive tab lead 29b. That is, the negative tab lead 29a may be the second electrode terminal portion to which the acoustic receiver 11b is attached, and the positive tab lead 29b may be the first electrode terminal portion to which the acoustic radiator 11a is attached. That is, the acoustic radiator 11a and the acoustic receiver 11b are each attached to different electronic terminal portions.

[0012] Further, the attachment locations of the acoustic radiator 11a and the acoustic receiver 11b are not limited to the negative tab lead 29a and the positive tab lead 29b, and may be provided on each of the two bus bars connected to the battery 200. In this case, the two bus bars constitute a first electrode terminal portion and a second electrode terminal portion electrically connected to the current collector 23, similar to the negative tab lead 29a and the positive tab lead 29b. Further, the acoustic radiator 11a may be provided on an electronically conductive member directly connected to the first electrode terminal portion, and the acoustic receiver 11b may be provided on an electronically conductive member directly connected to the second electrode terminal portion.

[0013] The acoustic radiator 11a emits an acoustic signal of a predetermined frequency and acoustic intensity (amplitude) based on a control command from the determination unit 12. The acoustic signal emitted from the acoustic radiator 11a is incident into the battery 200 through the negative tab lead 29a. Then, after passing through by transmitting and / or reflecting inside the battery 200, the acoustic signal is received by the acoustic receiver 11 as a measured acoustic signal through the positive tab lead 29b.

[0014] The determination unit 12 determines the internal state of the battery 200 based on the measured acoustic signal received by the acoustic receiver 11. Specifically, the determination unit 12 acquires, from the storage unit 13, the frequency and acoustic intensity of the initial acoustic signal stored in the storage unit 13. Then, the determination unit 12 determines whether an abnormality has occurred inside the battery 200 by comparing the initial acoustic signal with the measured acoustic signal. That is, the determination unit 12 detects a change in the internal state of the battery 200 as a change in the reception result of the acoustic signal, and determines whether an abnormality has occurred inside the battery 200. Further, the determination unit 12 may determine the presence or absence of an abnormality based only on the measured acoustic signal using a learned model obtained by machine learning the characteristics of the acoustic signal at the time of abnormality occurrence without comparing the initial acoustic signal with the measured acoustic signal.

[0015] The initial acoustic signal is an acoustic signal received by the acoustic receiver 11b when no abnormality has occurred in the battery 200. That is, when the battery 200 is normal, the acoustic receiver 11b receives the acoustic signal radiated by the acoustic radiator 11a, and the storage unit 13 stores the reception result of the acoustic signal as information on the initial acoustic signal. The initial acoustic signal stored in the storage unit 13 is updated every time a predetermined period elapses.

[0016] Next, with reference to FIGS. 2 and 3, the battery internal state detection method executed by the battery internal state detection device 100 according to the present embodiment will be described in more detail. First, as shown in FIG. 2, in step S1, the acoustic radiator 11a radiates an acoustic signal based on a control command from the determination unit 12. Then, in step S2, the acoustic receiver 11 receives the acoustic signal that has passed through the inside of the battery 200 as a measured acoustic signal.

[0017] Next, in step S3, as shown in the graph of FIG. 3, the determination unit 12 determines whether the difference D1 between the measured acoustic intensity A1 of the measured acoustic signal at a predetermined frequency F1 and the initial acoustic intensity A0 of the initial acoustic signal is equal to or greater than a predetermined value. In the present embodiment, the predetermined frequency F1 is the frequency corresponding to the peaks of the measured acoustic intensity A1 and the initial acoustic intensity A0, but is not limited thereto. Also, in step S3, the determination unit 12 may determine whether the difference D1 between the maximum value A1m of the measured acoustic intensity A1 in a predetermined frequency range Fa and the maximum value A0m of the initial acoustic intensity A0 is equal to or greater than a predetermined value.

[0018] Then, in step S3, when it is determined that "the difference D1 between the measured acoustic intensity A1 and the initial acoustic intensity A0 at a predetermined frequency F1 is equal to or greater than a predetermined value" or "the difference D1 between the maximum value A1m of the measured acoustic intensity A1 and the maximum value A0m of the initial acoustic intensity A0 in a predetermined frequency range Fa is equal to or greater than a predetermined value", in step S4, the determination unit 12 determines that an abnormality has occurred inside the battery 200. Note that the abnormality inside the battery 200 refers to, for example, the depletion of the battery 200 (the occurrence of a lack part of the electrolytic solution that fills the voids in the electrode mixture layer 24 and the separator 27 due to the decomposition of the electrolytic solution and the accompanying gas generation), the occurrence of cracks in the active material, the occurrence of destruction of the microstructure such as cracks in the electrode mixture layer 24, and the like.

[0019] On the other hand, in step S3, when it is determined that "the difference D1 between the measured acoustic intensity A1 and the initial acoustic intensity A0 at a predetermined frequency F1 is less than a predetermined value" or "the difference D1 between the maximum value A1m of the measured acoustic intensity A1 and the maximum value A0m of the initial acoustic intensity A0 in a predetermined frequency range Fa is less than a predetermined value", the process returns to step S1.

[0020] As described above, the battery internal state detection device 100 according to the present embodiment is provided on a first electrode terminal portion (negative electrode side tab lead 29a) electrically connected to the current collector 23 or an electronic conductive member directly connected to the first electrode terminal portion, and emits an acoustic signal. An acoustic radiator 11a, a second electrode terminal portion (positive electrode side tab lead 29b) electrically connected to the current collector 23, or an acoustic receiver 11b provided on an electronic conductive member directly connected to the second electrode terminal portion, and receives the acoustic signal as a measured acoustic signal, and a determination unit 12 that determines the internal state of the battery 200 based on the measured acoustic signal. Thereby, the acoustic signal radiated by the acoustic radiator 11a of the battery internal state detection device 100 is transmitted to the acoustic receiver 11b through a member formed of a material having a low acoustic impedance such as a current collector foil (for example, copper or aluminum). Therefore, attenuation of the acoustic signal is suppressed, and the acoustic receiver 11b can detect the acoustic signal with higher sensitivity. Therefore, the battery internal state detection device 100 can accurately detect the internal state of the battery 200. Further, if the acoustic radiator 11a and the acoustic receiver 11b are provided outside the battery exterior portion 22 of the battery 200, the acoustic signal is attenuated because it is transmitted through the power storage element 21 and the battery exterior portion 22. On the other hand, when the acoustic radiator 11a and the acoustic receiver 11b are provided on the electrode terminal portion (the first electrode terminal portion and the second electrode terminal portion) or an electronic conductive member electrically connected to the electrode terminal portion as in the present embodiment, the number of members through which the acoustic signal passes is small, and attenuation of the acoustic signal can be suppressed. Therefore, the battery internal state detection device 100 can accurately detect the internal state of the battery 200 even if the battery 200 is a large laminated battery. Further, since the battery internal state detection device 100 determines the internal state of the battery 200 based on the acoustic signal, the internal state of the battery 200 can be detected even when the battery 200 is not being charged or discharged.

[0021] Further, the battery internal state detection device 100 further includes a storage unit 13 that stores the acoustic signal of the battery 200 during normal operation as an initial acoustic signal, and the determination unit 12 determines whether an abnormality has occurred inside the battery 200 by comparing the measured acoustic signal with the initial acoustic signal. Thereby, the battery internal state detection device 100 can detect the change inside the battery 200 as the change in the absorption state or reflection state of the acoustic signal by comparing the measured acoustic signal with the initial acoustic signal, and can determine the presence or absence of an abnormality.

[0022] Further, when the measured acoustic intensity A1 of the measured acoustic signal at a predetermined frequency F1 and the initial acoustic intensity A0 of the initial acoustic signal differ by a predetermined value or more, the battery internal state detection device 100 determines that an abnormality has occurred inside the battery 200. Thereby, the battery internal state detection device 100 can detect the change inside the battery 200 as the change in the acoustic intensity at a predetermined frequency, and can determine the presence or absence of an abnormality.

[0023] Further, the battery internal state detection device 100 may determine that an abnormality has occurred inside the battery 200 when the maximum value A1m of the measured acoustic intensity A1 in a predetermined frequency range Fa and the maximum value A0m of the initial acoustic intensity A0 differ by a predetermined value or more. Thereby, the battery internal state detection device 100 can detect the change inside the battery 200 as the change in the maximum value of the acoustic intensity in a predetermined frequency range Fa, and can determine the presence or absence of an abnormality.

[0024] Further, the storage unit 13 of the battery internal state detection device 100 updates the initial acoustic signal every time a predetermined period elapses. Thereby, since the battery internal state detection device 100 can acquire the initial acoustic signal in accordance with the change over time of the internal state of the battery 200, it can accurately determine the presence or absence of an abnormality.

[0025] 《Second Embodiment》 Next, a method for detecting the internal state of a battery according to the second embodiment of the present invention will be described with reference to FIGS. 4 and 5. Note that the battery internal state detection device 100 that executes the battery internal state detection method according to the second embodiment has the same configuration as that shown in FIG. 1. Also, in the following description, the same reference numerals as those described in FIGS. 1 to 3 denote the same or similar components, and thus detailed descriptions thereof are omitted.

[0026] As shown in FIG. 4, after the acoustic radiator 11a emits an acoustic signal in step S1 and the acoustic receiver 11 receives the measured acoustic signal in step S2, in step S13, as shown in the graph of FIG. 5, the determination unit 12 determines whether the difference D2 between the measured acoustic peak frequency Fp1 and the initial acoustic peak frequency Fp0 is equal to or greater than a predetermined value. The measured acoustic peak frequency Fp1 is the frequency corresponding to the peak of the measured acoustic intensity A1 of the measured acoustic signal. That is, when the frequency of the measured acoustic signal is the measured acoustic peak frequency Fp1, the measured acoustic intensity A1 of the measured acoustic signal becomes the peak value Ap1. Also, the initial acoustic peak frequency Fp0 is the frequency corresponding to the peak of the initial acoustic intensity A0 of the initial acoustic signal. That is, when the frequency of the initial acoustic signal is the initial acoustic peak frequency Fp0, the initial acoustic intensity A0 of the initial acoustic signal becomes the peak value Ap0. In the example shown in FIG. 5, the peak value Ap1 of the measured acoustic intensity A1 and the peak value Ap0 of the initial acoustic intensity A0 are the same value, but the present invention is not limited thereto, and they may be different from each other.

[0027] Then, in step S13, when it is determined that "the difference D2 between the measured acoustic peak frequency Fp1 and the initial acoustic peak frequency Fp2 is equal to or greater than a predetermined value", in step S4, the determination unit 12 determines that an abnormality has occurred inside the battery 200. On the other hand, in step S13, when it is determined that "the difference D2 between the measured acoustic peak frequency Fp1 and the initial acoustic peak frequency Fp2 is less than a predetermined value", the process returns to step S1.

[0028] As described above, the battery internal state detection device 100 according to the present embodiment acquires the measured acoustic peak frequency Fp1 corresponding to the peak of the measured acoustic intensity A1, acquires the initial acoustic peak frequency Fp0 corresponding to the peak of the initial acoustic intensity A0 of the initial acoustic signal, and determines that an abnormality has occurred inside the battery 200 when the measured acoustic peak frequency Fp1 and the initial acoustic peak frequency Fp0 differ by a predetermined value or more. Thereby, the battery internal state detection device 100 can detect a change inside the battery 200 as a change in the frequency corresponding to the peak of the acoustic intensity, and can determine the presence or absence of an abnormality.

[0029] 《Third Embodiment》 Next, a battery internal state detection method according to the third embodiment of the present invention will be described with reference to FIGS. 6 and 7. Note that the battery internal state detection device 100 that executes the battery internal state detection method according to the third embodiment has the same configuration as that shown in FIG. 1.

[0030] As shown in FIG. 6, after the acoustic radiator 11a emits an acoustic signal in step S1 and the acoustic receiver 11 receives the measured acoustic signal in step S2, in step S23, as shown in the graph of FIG. 7, the determination unit 12 determines whether the difference D3 between the measured acoustic detection time T1 and the initial acoustic detection time T0 is equal to or greater than a predetermined time. The measured acoustic detection time T1 is the time from the acoustic emission start timing Te at which the acoustic radiator 11a starts emitting the acoustic signal until the acoustic receiver 11b receives a measured acoustic signal having an acoustic intensity equal to or greater than a predetermined value Ax. The initial acoustic detection time T0 is the time from the acoustic emission start timing Te until the acoustic receiver 11b receives an initial acoustic signal having an acoustic intensity equal to or greater than a predetermined value Ax.

[0031] If it is determined in step S23 that "the difference D3 between the measured acoustic detection time T1 and the initial acoustic detection time T0 is equal to or greater than a predetermined time", then in step S4, the determination unit 12 determines that an abnormality has occurred inside the battery 200. On the other hand, if it is determined in step S23 that "the difference D3 between the measured acoustic detection time T1 and the initial acoustic detection time T0 is less than a predetermined time", the process returns to step S1.

[0032] As described above, the battery internal state detection device 100 according to the present embodiment acquires the actually measured acoustic detection time T1 and the initial acoustic detection time T0, and determines that an abnormality has occurred inside the battery 200 when the actually measured acoustic detection time T1 and the initial acoustic detection time T0 differ by a predetermined time or more. Thereby, the battery internal state detection device 100 can detect a change inside the battery 200 as a temporal shift of the peak of the acoustic intensity, and determine the presence or absence of an abnormality.

[0033] In the above, the negative electrode side tab lead 29a corresponds to the first electrode terminal portion. Also, the positive electrode side tab lead 29b corresponds to the second electrode terminal portion.

Explanation of Reference Numerals

[0034] 100... Battery internal state detection device 200... Battery 11a... Acoustic radiator 11b... Acoustic receiver 12... Determination unit 13... Storage unit 23... Current collector 24... Electrode binder layer 29a... Negative electrode side tab lead (first electrode terminal portion) 29b... Positive electrode side tab lead (second electrode terminal portion)

Claims

1. A battery internal state detection device for detecting the internal state of a battery having a laminated structure of an electrode mixture layer containing an electrode active material and a current collector, an acoustic radiator provided on a first electrode terminal portion electrically connected to the current collector or an electronic conductive member directly connected to the first electrode terminal portion, which radiates an acoustic signal; a second electrode terminal portion that is an electrode terminal portion different from the first electrode terminal portion and is electrically connected to the current collector, or an acoustic receiver provided on an electronic conductive member directly connected to the second electrode terminal portion, which receives the acoustic signal as a measured acoustic signal; and a determination unit that determines the internal state of the battery based on the measured acoustic signal. A battery internal state detection device.

2. further comprising a storage unit that stores the acoustic signal of the battery during normal operation as an initial acoustic signal, wherein the determination unit determines whether an abnormality has occurred inside the battery by comparing the measured acoustic signal with the initial acoustic signal. The battery internal state detection device according to claim 1.

3. The determination unit according to claim 2, wherein when the measured acoustic intensity of the measured acoustic signal at a predetermined frequency and the initial acoustic intensity of the initial acoustic signal differ by a predetermined value or more, it is determined that an abnormality has occurred inside the battery. The battery internal state detection device described.

4. The determination unit according to claim 2, wherein when the maximum value of the measured acoustic intensity of the measured acoustic signal in a predetermined frequency range and the maximum value of the initial acoustic intensity of the initial acoustic signal differ by a predetermined value or more, it is determined that an abnormality has occurred inside the battery. The battery internal state detection device described.

5. The determination unit, acquires a measured acoustic peak frequency corresponding to a peak of the measured acoustic intensity of the measured acoustic signal, acquires an initial acoustic peak frequency corresponding to a peak of the initial acoustic intensity of the initial acoustic signal, and when the measured acoustic peak frequency and the initial acoustic peak frequency differ by a predetermined value or more, determines that an abnormality has occurred inside the battery. The battery internal state detection device according to claim 2.

6. The determination unit, acquires a measured acoustic detection time from the acoustic radiation start timing when the acoustic radiator starts radiating the acoustic signal until the acoustic receiver receives the measured acoustic signal having an acoustic intensity equal to or greater than a predetermined value, and acquires an initial acoustic detection time from the acoustic radiation start timing until the acoustic receiver receives the initial acoustic signal having an acoustic intensity equal to or greater than a predetermined value. The battery internal state detection device according to claim 2, wherein when the actually measured acoustic detection time and the initial acoustic detection time differ by a predetermined time or more, it is determined that an abnormality has occurred inside the battery.

7. The battery internal state detection device according to claim 2, wherein the storage unit updates the initial acoustic signal every time a predetermined period elapses.

8. A battery internal state detection method for detecting the internal state of a battery having a laminated structure of an electrode mixture layer containing an electrode active material and a current collector, using a battery internal state detection device, wherein the battery internal state detection device radiates an acoustic signal through a first electrode terminal portion electrically connected to the current collector or an electron conductive member electrically connected to the first electrode terminal portion, receives the acoustic signal as an actually measured acoustic signal through a second electrode terminal portion different from the first electrode terminal portion and electrically connected to the current collector or an electron conductive member electrically connected to the second electrode terminal portion, and determines the internal state of the battery based on the actually measured acoustic signal.

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