JP2010040318A - Method and device for detecting ae signal generating part of secondary battery - Google Patents

Abstract

Proposal of a method for detecting a site where an AE signal is generated in a secondary battery The method for detecting a site where an AE signal is generated in a secondary battery is an AE signal attached to a plurality of positions of a battery case. An AE signal generated in the battery case 300 is detected from the detection sensors 11 and 12. Then, based on the time at which the plurality of AE signal detection sensors 11 and 12 detect the AE signal, the site where the secondary battery 1000 generates the AE signal is detected. According to this AE signal generation site detection method, the site where the AE signal is generated by the secondary battery can be detected.
[Selection] Figure 4

Description

  The present invention relates to a method for detecting an AE signal generation site of a secondary battery configured in a case. Here, the “AE signal” means an acoustic emission signal.

  For example, Japanese Patent Application Laid-Open No. 7-6795 discloses a technique for detecting an AE signal generated from the inside of a battery with respect to a sealed lead acid battery. In this publication, depending on the frequency of the detected AE signal, an AE signal having a frequency of 50 to 150 kHz is caused by gas generation, and a signal having a frequency of 150 kHz or more is caused by destruction of internal components.

Japanese Patent Application Laid-Open No. 7-85892 discloses a method using an AE signal as a storage battery charging method. The main invention disclosed in the publication is to switch the charging of the battery from constant current charging to constant voltage charging when the AE signal of the storage battery is measured and the measured value is differentiated and as a result, the measured value shows a tendency to increase rapidly. That's it.
Japanese Patent Laid-Open No. 2006-147513 discloses that an AE signal is measured for an electrochemical characteristic measuring cell having a structure in which an O-ring or a sealing material is disposed outside a concave portion of a cell body and can be sealed with a lid. Is disclosed. In this publication, an AE signal generated in a cell due to volume expansion, stress generation, and vesicular destruction associated with charge / discharge is measured.
In Japanese Patent Laid-Open No. 2005-291832, as a method for diagnosing battery deterioration, an ultrasonic wave is applied from outside the measured battery to the measured battery, and the ultrasonic wave is detected outside the measured battery to detect the battery. Diagnosing the deterioration of the measurement battery is disclosed.
Japanese Unexamined Patent Publication No. 7-6795 Japanese Patent Laid-Open No. 7-85892 JP 2006-147513 A JP 2005-291832 A

  The above-mentioned patent documents generally relate to a battery or a cell for measuring electrochemical characteristics, and disclose that an AE signal is detected to detect a charged state or a deteriorated state. However, none of the methods discloses a method for detecting a site that generates an AE signal. The present invention proposes a method for detecting a site where an AE signal is generated in a secondary battery.

  The secondary battery AE signal generation site detection method according to the present invention is a method for detecting an AE signal generation site of a secondary battery configured in a case. That is, AE signals are detected by AE signal detection sensors attached to a plurality of positions on the case. And the site | part which produced the AE signal with the secondary battery is detected based on the time difference which the several AE signal detection sensor detected the AE signal. According to this AE signal generation site detection method, the site where the AE signal is generated by the secondary battery can be detected.

  For example, when the case is provided with a positive electrode terminal and a negative electrode terminal of a secondary battery, the AE signal detection sensor may be attached to the positive electrode terminal and the negative electrode terminal, respectively. In this case, depending on which AE signal detection sensor detects the AE signal first, whether the site where the AE signal is generated in the secondary battery is closer to the positive electrode than the negative electrode or closer to the negative electrode than the positive electrode It can be detected.

  In addition, this AE signal generation site detection method can be applied to a secondary battery having a wound electrode body in which a positive electrode sheet and a negative electrode sheet are overlapped and wound via a strip-shaped separator in a case. In this case, the positive electrode sheet is coated with an electrode material containing a positive electrode active material on a strip-shaped current collector sheet, and the negative electrode sheet is coated with an electrode material containing a negative electrode active material on a strip-shaped current collector sheet. . The positive electrode terminal is connected to the current collector sheet of the positive electrode sheet, and the negative electrode terminal is connected to the current collector sheet of the negative electrode sheet. The AE signal detection sensor may be attached to the positive terminal and the negative terminal, respectively. Even in this case, it is possible to detect whether the site where the AE signal is generated in the secondary battery is a site near the positive electrode or a site near the negative electrode in the wound electrode body.

  When the case is a substantially rectangular parallelepiped metal case, at least three AE signal detection sensors may be attached to one surface of the case. In this case, among the AE signal detection sensors, a portion where the AE signal is generated in the secondary battery can be detected based on the time when at least three AE signal detection sensors detect the AE signal.

  Hereinafter, an example of an AE signal generation site detection method for a secondary battery according to an embodiment of the present invention and an apparatus embodying the method will be described with reference to the drawings.

In such a secondary battery, for example, an event such as generation of a gas accompanying a chemical reaction at the time of discharging or charging, an event that the active material contained in the electrode material breaks, or an internal short circuit between the positive electrode and the negative electrode occurs. Since these events are events that occur in the battery case, it is extremely difficult to determine which part of the secondary battery is occurring from the outside.
These events give rise to an AE signal. The inventor considered that it is possible to determine in which part of the secondary battery the AE signal occurs based on the AE signal. However, it has been found that in the secondary battery, even if the AE signal detection sensor is simply attached to the battery case and the AE signal is detected, the site where the AE signal is generated cannot be accurately identified in the secondary battery. As a result of intensive studies on this phenomenon, in a secondary battery in which a plurality of materials are stacked in a battery case and further immersed in an electrolyte, the AE signal is transmitted at a transmission speed depending on the material on the transmission path. Is different. For this reason, the knowledge that the site | part which produced AE signal simply cannot be specified was acquired.

  In the above-mentioned patent documents, a technique for detecting a charged state or a deteriorated state of a battery by detecting an AE signal of the battery is described, but in any case, in which part of the secondary battery the AE signal is generated. It is not a technology to detect. If it can be detected in which part of the secondary battery the AE signal is generated, it can be used for various inspections of the secondary battery. For example, in a laboratory or the like, if it is possible to detect at which part of the secondary battery the AE signal is generated, the part where the abnormality has occurred can be detected, and the cause of the abnormality of the secondary battery can be grasped more accurately. Become. Further, for example, as shown in FIG. 8, the deterioration status of the secondary battery 1000 mounted on the vehicle 1 can be diagnosed more accurately.

Based on this knowledge, the present inventor has devised a completely new AE signal generation site detection method capable of detecting a site where an AE signal is generated in a secondary battery.
That is, this AE signal generation site detection method of the secondary battery is based on the AE signal generated in the battery case 300 from the AE signal detection sensors 11 and 12 attached to a plurality of positions of the battery case 300 as shown in FIG. Is detected. Then, based on the time at which the plurality of AE signal detection sensors 11 and 12 detect the AE signal, the site where the secondary battery 1000 generates the AE signal is detected. According to this AE signal generation site detection method, the site where the AE signal is generated by the secondary battery can be detected. Hereinafter, an AE signal generation site detection method according to an embodiment of the present invention will be described using a lithium-ion secondary battery as an example.

In this embodiment, the lithium ion secondary battery is configured in a metal battery case 300 as shown in FIG. The battery case 300 accommodates the wound electrode body 100.
For example, as shown in FIG. 2, the wound electrode body 100 is formed by winding a positive electrode sheet 101, a first separator 102, a negative electrode sheet 103, and a second separator 104 in order. The positive electrode sheet 101 is a positive electrode sheet, and the negative electrode sheet 103 is a negative electrode sheet. In the following description, the positive electrode sheet 101 and the negative electrode sheet 103 are collectively referred to as “electrode sheet” as appropriate.

In this embodiment, the positive electrode sheet 101 is coated with an electrode material 132 containing a positive electrode active material on both surfaces of a current collector sheet 131 (positive electrode current collector) made of an aluminum foil. Examples of the positive electrode active material included in the electrode material 132 include lithium manganate (LiMn ₂ O ₄ ), lithium cobaltate (LiCoO ₂ ), and lithium nickelate (LiNiO ₂ ).
In this embodiment, the negative electrode sheet 103 is coated with an electrode material 142 containing a negative electrode active material on both surfaces of a current collector sheet 141 (negative electrode current collector) made of copper foil. Examples of the negative electrode active material included in the electrode material 142 include carbon-based materials such as graphite and amorphous carbon, lithium-containing transition metal oxides, and transition metal nitrides.
Separator 102,104 is a film | membrane which an ionic substance can permeate | transmit, and the microporous film made from a polypropylene is used in this embodiment.

  In this embodiment, the electrode materials 132 and 142 are applied so as to be biased to one side in the width direction of the current collector sheets 131 and 141, and are applied to the edges of the current collector sheets 131 and 141 on the opposite side in the width direction. It has not been. Of the positive and negative electrode sheets 101 and 103, the portions where the current collector sheets 131 and 141 are coated with the electrode materials 132 and 142 are referred to as application portions 101 a and 103 a, and the current collector sheets 131 and 141 are electrode material 132. , 142 are referred to as uncoated portions 101b and 103b.

  FIG. 3 is a cross-sectional view in the width direction showing a state in which the positive electrode sheet 101, the first separator 102, the negative electrode sheet 103, and the second separator 104 are sequentially stacked. The coating part 101a of the positive electrode sheet 101 and the coating part 103a of the negative electrode sheet 103 are opposed to each other with the separators 102 and 104 interposed therebetween. As shown in FIGS. 2 and 3, the uncoated portions 101 b and 103 b of the positive electrode sheet 101 and the negative electrode sheet 103 are separators on both sides in a direction (winding axis direction) orthogonal to the winding direction of the wound electrode body 100. 102 and 104, respectively. The uncoated portions 101b and 103b of the positive electrode sheet 101 and the negative electrode sheet 103 form the positive electrode and negative electrode current collectors 101b1 and 103b1 of the wound electrode body 100, respectively.

The wound electrode body 100 is accommodated in a battery case 300 as shown in FIG. The battery case 300 is provided with a positive electrode terminal 301 and a negative electrode terminal 303. The positive electrode terminal 301 is electrically connected to the positive electrode current collector 101b1 (see FIG. 2) of the wound electrode body 100. The negative electrode terminal 303 is electrically connected to the negative electrode current collector 103b1 (see FIG. 2) of the wound electrode body 100. An electrolyte is injected into the battery case 300. The electrolytic solution can be composed of a nonaqueous electrolytic solution such as a mixed solvent such as diethyl carbonate and ethylene carbonate containing an appropriate amount of an appropriate electrolyte salt (for example, a lithium salt such as LiPF ₆ ).
In such a lithium ion secondary battery, a predetermined chemical reaction occurs during discharging. Then, lithium ions go back and forth between the coating part 101 a of the positive electrode sheet 101 and the coating part 103 a of the negative electrode sheet 103 through the separators 102 and 104.
In such a lithium ion secondary battery, various events that generate an AE signal include, for example, the generation of a gas accompanying a chemical reaction at the time of charge and discharge, the event that an active material contained in the electrode material is broken, the positive electrode and the negative electrode There is an internal short circuit.

In this embodiment, the AE signal generation site detection apparatus 10 includes a plurality of AE signal detection sensors 11 and 12 and an AE signal generation site detection unit 16, as shown in FIG. In the figure, reference numeral 17 denotes an amplifier that amplifies the AE signal detected by the AE signal detection sensors 11 and 12.
The AE signal detection sensors 11 and 12 are sensors that detect AE signals, respectively. As the AE signal detection sensors 11 and 12, it is preferable to employ a sensor that is suitable for being attached to the battery case 300 among various known sensors.

  The AE signal generation site detector 16 detects a site where the AE signal is generated in the secondary battery 1000 based on the time when the AE signal detection sensors 11 and 12 detect the AE signal. The AE signal generation site detection unit 16 includes, for example, a storage unit such as a non-volatile memory and an arithmetic processing unit such as a CPU, and an electronic arithmetic processing device (computer) that performs predetermined processing according to a preset program ).

  For example, in this embodiment, the AE signal detection sensors 11 and 12 are attached to the positive terminal 301 and the negative terminal 303. Based on the time when the AE signal detection sensors 11 and 12 detect the AE signal, the AE signal generation site detection unit 16 determines whether the site where the AE signal is generated in the secondary battery 1000 is closer to the positive electrode than the negative electrode, It is detected whether the part is closer to the negative electrode than the positive electrode.

That is, according to the knowledge of the present inventor, the metal has a higher transmission speed of the AE signal than the electrolytic solution, the electrode material, the separator and the like. The positive electrode terminal 301 is connected to a positive electrode current collector (current collector sheet 131) made of a metal foil, and the negative electrode terminal 303 is a negative electrode current collector (current collector) made of a metal foil. The body sheet 141) is connected.
For example, an AE signal generated between the positive electrode sheet 101 and the negative electrode sheet 103 is transmitted to the positive electrode terminal 301 through the positive electrode current collector sheet 131 and is transmitted to the negative electrode terminal 303 through the negative electrode current collector sheet 141. At this time, there is a slight difference between the time transmitted to the positive electrode terminal 301 and the time transmitted to the negative electrode terminal 303 depending on the portion where the AE signal is generated.

For example, when the site where the AE signal is generated in the secondary battery 1000 is closer to the positive electrode than the negative electrode (including the positive electrode), the positive electrode terminal 301 is connected to the positive electrode terminal 301 rather than the AE signal detection sensor 12 attached to the negative electrode terminal 303. The attached AE signal detection sensor 11 detects the AE signal first.
Therefore, when the AE signal detection sensor 11 attached to the positive electrode terminal 301 detects the AE signal first, the site where the AE signal is generated in the secondary battery 1000 is closer to the positive electrode than the negative electrode (the positive electrode is connected). Including).
On the contrary, when the AE signal detection sensor 12 attached to the negative electrode terminal 303 detects the AE signal first, the portion where the AE signal is generated in the secondary battery 1000 is closer to the negative electrode than the positive electrode (negative electrode Can be determined).
Thus, in this embodiment, the part where the AE signal is generated in the secondary battery 1000 is closer to the positive electrode than the negative electrode depending on which of the AE signal detection sensors 11 and 12 detects the AE signal first. It can be detected whether it is a part or a part closer to the negative electrode than the positive electrode.

  As described above, the secondary battery is exemplified as a battery having a structure in which the wound electrode body is accommodated in the battery case, but is not limited to such a structure. That is, the form of the secondary battery can be applied to various types of secondary batteries such as a so-called cylindrical type and laminate type, and is not limited to the shape of the battery case. Even in this case, the AE signal detection sensor may be attached to the positive terminal and the negative terminal of the secondary battery provided in the case. As a result, depending on which AE signal detection sensor detects the AE signal first, whether the site where the AE signal is generated in the secondary battery is closer to the positive electrode than the negative electrode or closer to the negative electrode than the positive electrode Can be detected.

Next, another embodiment of the secondary battery AE signal generation site detection method will be described.
In this embodiment, the battery case 300 is formed of a substantially rectangular parallelepiped metal (for example, aluminum alloy) case. In this case, as shown in FIG. 5, a plurality (three in this embodiment) of AE signal detection sensors 11, 12, and 13 may be attached to the side surface 300 a of the battery case 300. In this case, the site S where the AE signal is generated can be specified in the battery case 300 based on the time when the plurality of AE signal detection sensors 11, 12, 13 detect the AE signal.

  That is, the AE signal generated in the battery case 300 is first transmitted to the closest side surface 300a of the battery case 300 as shown in FIG. Then, as shown in FIGS. 5 and 6, the AE signal is transmitted from the position transmitted to the battery case 300 to the AE signal detection sensors 11, 12, and 13 through the surface of the battery case 300. In this case, since the transmission speed of the AE signal through the surface of the battery case 300 is considered to be substantially constant, the AE signal is based on the time (time difference) when the AE signal is transmitted to each of the AE signal detection sensors 11, 12, 13. Can first be transmitted to the battery case 300.

  That is, for example, as shown in FIG. 7, the AE signals are detected by the three AE signal detection sensors 11, 12, and 13. In the example of FIG. 7, the horizontal axis indicates time, and the vertical axis indicates the strength of the AE signal. The signal A is an AE signal detected by the AE signal detection sensor 11, the signal B is an AE signal detected by the AE signal detection sensor 12, and the signal C is an AE signal detected by the AE signal detection sensor 13. . In this embodiment, the AE signal generation site detector 16 calculates a time difference tAB between the AE signal A and the AE signal B, a time difference tBC between the AE signal B and the AE signal C, and a time difference tCA between the AE signal C and the AE signal A. . Based on the time difference tAB, the time difference tBC, and the time difference tCA, on the side surface 300a of the battery case 300 to which the AE signal detection sensors 11, 12, and 13 are attached, the portion where the AE signal is generated in the secondary battery 1000 is It can be detected in a plane.

  Thus, when the battery case 300 is a substantially rectangular parallelepiped metal case, it is preferable to attach at least three AE signal detection sensors 11, 12, and 13 to one surface of the battery case 300. Of the AE signal detection sensors 11, 12, and 13, the part that generates the AE signal in the secondary battery 1000 based on the time at which at least three AE signal detection sensors 11, 12, and 13 detect the AE signal. Should be detected. In this case, the number of AE signal detection sensors 11, 12, and 13 attached to the battery case 300 may be three or more.

  As described above, the AE signal generation site detection method and apparatus for a secondary battery according to an embodiment of the present invention have been described. However, the AE signal generation site detection method for a secondary battery according to the present invention is limited to the above-described embodiment. Not.

  For example, the secondary battery is exemplified by a lithium-ion secondary battery, but can be applied to various secondary batteries (storage batteries) such as a nickel-hydride secondary battery.

Sectional drawing which shows the structural example of a secondary battery. The figure which shows the structural example of a wound electrode body. Sectional drawing which shows the structural example of a wound electrode body. The figure which shows the structural example of the apparatus which actualized the AE signal generation site | part detection method of the secondary battery which concerns on this invention. The figure which shows the structural example of the apparatus which actualized the AE signal generation site | part detection method of the secondary battery which concerns on other embodiment which concerns on this invention. The figure which shows the AE signal generation site | part detection method of the secondary battery which concerns on other embodiment which concerns on this invention. The figure which shows the example of the AE signal detected with the AE signal generation site | part detection method of the secondary battery which concerns on other embodiment which concerns on this invention. The figure which shows the vehicle carrying a secondary battery as a power supply.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 10 AE signal generation | occurrence | production site | part detection apparatus 11 AE signal detection sensor 12 AE signal detection sensor 13 AE signal detection sensor 16 AE signal generation site | part detection part 17 Amplifier 100 Winding electrode body 101 Positive electrode sheet | seat (electrode sheet)
101a Coating part 101b Uncoated part 101b1 Positive electrode current collector 102 Separator (first separator)
103 Negative electrode sheet (electrode sheet)
103a Coating part 103b Uncoated part 103b1 Negative electrode current collector 104 Separator (second separator)
131 Current collector sheet 132 Electrode material 141 Current collector sheet 142 Electrode material 300 Battery case (case)
300a Side surface 301 of battery case Positive electrode terminal 303 Negative electrode terminal 1000 Secondary battery SAE signal part

Claims (5)

A method for detecting an AE signal generation site of a secondary battery configured in a case,
AE signals are detected by AE signal detection sensors attached to a plurality of positions of the case,
An AE signal generation site detection method for a secondary battery, wherein a site where an AE signal is generated in the secondary battery is detected based on times when the plurality of AE signal detection sensors detect an AE signal. The case is provided with a positive terminal and a negative terminal of a secondary battery, and the AE signal detection sensor is attached to the positive terminal and the negative terminal,
Depending on which AE signal detection sensor detects the AE signal first, it is detected whether the site that caused the AE signal in the secondary battery is closer to the positive electrode than the negative electrode or closer to the negative electrode than the positive electrode, The secondary battery AE signal generation site detection method according to claim 1. The secondary battery includes a positive electrode sheet obtained by applying an electrode material containing a positive electrode active material to a belt-like current collector sheet, and a negative electrode sheet obtained by applying an electrode material containing a negative electrode active material to a belt-like current collector sheet. A wound electrode body that is wound with being overlapped via a separator is provided in the case,
The method for detecting an AE signal generation site of a secondary battery according to claim 2, wherein the positive electrode terminal is connected to a current collector sheet of a positive electrode sheet, and the negative electrode terminal is connected to a current collector sheet of a negative electrode sheet. .   The case is a substantially rectangular parallelepiped metal case, and at least three AE signal detection sensors are attached to one surface of the case. Among the AE signal detection sensors, at least three AE signal detection sensors receive an AE signal. The method of detecting an AE signal generation site in a secondary battery according to claim 1, wherein a site where an AE signal is generated in the secondary battery is detected based on the detected time. An AE signal generation site detection device for a secondary battery configured in a case,
An AE signal detection sensor attached to a plurality of positions of the case;
An AE signal of a secondary battery, comprising: an AE signal generation site detector for detecting a site where an AE signal is generated in the secondary battery based on times when the plurality of AE signal detection sensors detect AE signals. Generation site detection device.

Images