JP2008243439A - Abnormality detecting device of battery and abnormality detecting method of battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an abnormality detecting device of a battery and an abnormality detecting method of the battery capable of detecting defects of an inner resin layer (an insulating layer) of an outer packaging material generated in manufacturing. <P>SOLUTION: The existence or nonexistence of defects of an insulating layer (a polypropylene resin layer 27) of a laminated film 17 is decided based on a resistance value between a metal layer (an aluminum alloy layer 25) of the laminated film and one battery terminal (a negative electrode tab 15) by applying a DC voltage or an AC voltage between the metal layer (the aluminum alloy layer 25) of the laminated film 17 and one battery terminal (the negative electrode tab 15). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a battery abnormality detection device and a battery abnormality detection method using a laminate film whose metal layer surface is covered with an insulating layer as an exterior material, and in particular, a defect in an insulation layer of an exterior material that occurs during manufacturing. The present invention relates to a battery abnormality detection device and a battery abnormality detection method that can be detected.

  The power generation element with the positive and negative electrode plates laminated is housed together with the electrolyte in the exterior body formed of a laminate film with the metal layer surface covered with an insulating resin layer, and the battery terminals connected to the power generation element are packaged. A laminate type battery led out of the body is known.

As a conventional laminate type battery, for example, “laminated type battery, junction terminal, assembled battery, and assembled product disclosed in Japanese Patent Application Laid-Open No. 2004-247244 for the purpose of preventing corrosion of electrode terminals due to bonding of different metals. "Production method of battery" and "Laminate type secondary battery and its assembled battery" disclosed in Japanese Patent Application Laid-Open No. 2005-317312 for the purpose of suppressing stress concentration on the pasting portion of the laminate film .
JP 2004-247244 A JP 2005-317312 A

  In a battery using a laminate film in which the surface of such a metal layer is covered with an insulating resin layer as an exterior material, ensuring the insulation of the laminate film is a high voltage as an assembled battery for automotive applications, for example. It is important in terms of reliability when using it in. Therefore, a method for detecting defects in the insulating layer of the laminate film (exterior material) has been demanded.

  The present invention has been made in view of the above-described conventional circumstances, and an object of the present invention is to provide a battery abnormality detection device and a battery abnormality detection method capable of detecting a defect in an insulating layer of an exterior material.

  In order to solve the above-mentioned object, the present invention provides a power generation element formed by laminating a positive electrode plate and a negative electrode plate and an electrolyte solution inside an exterior body using a laminate film in which a metal layer surface is covered with an insulating layer. A battery abnormality detection device that seals and electrically connects positive and negative electrode terminals electrically connected to the power generation element to the outside of the exterior body, wherein the laminate film and the positive and negative electrode terminals A power source for applying a voltage between one of the electrode terminals, a resistance measuring means for measuring a resistance value between the laminate film and the one electrode terminal at the time of applying the voltage, and based on the measured resistance value And a defect presence / absence judging means for judging the presence / absence of a defect in the insulating layer of the laminate film.

  In the battery abnormality detection device and the battery abnormality detection method according to the present invention, a DC or AC voltage is applied between the metal layer of the laminate film and one battery terminal, and the metal layer of the laminate film and one battery terminal at that time are applied. Since the presence / absence of a defect in the insulating layer of the laminate film is determined based on the resistance value, the defect in the insulating layer of the exterior material can be detected with a simple configuration and method.

  Hereinafter, embodiments of the battery abnormality detection device and battery abnormality detection method of the present invention will be described in detail in the order of [Embodiment 1] and [Embodiment 2] with reference to the drawings.

[Example 1]
FIG. 1 is an explanatory diagram conceptually illustrating an aspect when battery abnormality detection is performed using the battery abnormality detection device according to the first embodiment of the present invention.

  An abnormality detection target battery is a laminate type battery in which a laminate film in which both surfaces of a metal layer are covered with an insulating layer is used as an exterior material, which will be described in detail later by exemplifying a specific structure. , 18 is an electrode laminate, 12 is a negative electrode current collector, 15 is a negative electrode tab (negative electrode terminal), 16 is a polypropylene film, and 17 is a laminate film.

  The measuring instrument 41 and the measuring terminals 42 and 43 are the battery abnormality detecting device according to the first embodiment. However, the measuring instrument 41 includes at least a metal layer of the laminate film 17 and one battery terminal (negative electrode tab 15). A power source for applying a DC voltage or an AC voltage, resistance measuring means for measuring a resistance value between the metal layer of the laminate film 17 and one battery terminal (negative electrode tab 15) at the time of applying the voltage, and laminating based on the measured resistance value Defect presence / absence judging means for judging the presence / absence of a defect in the insulating layer of the film 17.

  Next, the battery will be described in detail with reference to FIG. 2 and FIG. Here, FIG. 2A is a plan view of the whole battery, FIG. 2B is a sectional view of the whole battery, and FIG. 3A is an enlarged cross section of a portion A in FIG. 2B. FIG. 3B is an enlarged cross-sectional view of part B of FIG. 3A, and FIG. 3C is an enlarged cross-sectional view of part C of FIG.

  First, the overall structure will be described. The battery includes an electrode laminate 18 as a power generation element, and this electrode laminate 18 is disposed at the center of a laminate film 17 constituting the battery exterior. The electrode laminate 18 is welded over the entire periphery of the outer edge portion of the electrode laminate 18 so as to be sandwiched between the laminate films 17 in the thickness direction and sealed together with an electrolytic solution (not shown). .

  Next, as shown in FIG. 3 (c), the electrode laminate 18 is configured by sequentially laminating a plurality of positive electrode plates 1 and negative electrode plates 2 with separators 7 interposed from the viewpoint of short circuit suppression. The planar shape has a substantially rectangular shape. The positive electrode plate 1 is obtained by applying a positive electrode active material on both surfaces of a sheet-like positive electrode current collector 6, and the negative electrode plate 2 is obtained by applying a negative electrode active material on both surfaces of a sheet-like negative electrode current collector 12. is there. Each positive electrode plate 1 is connected to a positive electrode tab 14 as a positive electrode terminal via a positive electrode lead. Each negative electrode plate 2 is connected to a negative electrode tab 15 (not shown in FIG. 3) as a negative electrode terminal via a negative electrode lead.

  The positive electrode lead and the negative electrode lead are each formed of a metal foil. Specifically, for example, the positive electrode lead is formed from an aluminum foil, and the negative electrode lead is formed from a copper foil. And each positive electrode lead withdraw | derived from each positive electrode plate is piled up mutually in layers, and is joined to the positive electrode tab 14 by methods, such as welding. In addition, the respective negative electrode leads drawn from the respective negative electrode plates are stacked in layers and joined to the negative electrode tab 15 by a technique such as welding.

  The positive electrode lead is formed by extending the positive electrode current collector 6 to the positive electrode tab 14. Similarly, the negative electrode lead is formed by extending the negative electrode current collector 12 to the negative electrode tab 15.

  The positive electrode tab 14 and the negative electrode tab 15 are each formed of a metal plate. Specifically, for example, the positive electrode tab 14 is formed from an aluminum plate, and the negative electrode tab 15 is formed from a nickel plate. The positive electrode tab 14 and the negative electrode tab 15 are pulled out to the outside from the edges on the short side facing each other of the battery exterior, and function as a positive electrode terminal and a negative electrode terminal.

  Further, as shown in FIG. 3B, the laminate film 17 constituting the battery exterior has, for example, an aluminum alloy layer 25 as a base material, and PE (polyethylene) or PP (polypropylene) inside the aluminum alloy layer 25. A polymer resin layer 11 made of, for example, is coated. The laminate film 17 has a protective layer 23 made of nylon or the like bonded to the outside of the aluminum alloy layer 25 via an adhesive layer 24. Furthermore, in the region corresponding to the positive electrode tab 14 and the negative electrode tab 15 in the welded portion, a resin film 16 such as polypropylene is interposed on both surfaces of each tab 14, 15 from the viewpoint of improving the sealing performance. .

  Next, the manufacturing process will be described in detail. First, the positive electrode plate 1 was produced as follows. A powder (electrode mixture) obtained by mixing graphite as a conductive agent and polyvinylidene fluoride (PVDF) as a binder in spinel type lithium manganese oxide is dispersed in N-methyl-2-pyrrolidone (NMP) to obtain a slurry. Produced. The slurry was uniformly applied to both surfaces of a 20 [μm] thick aluminum foil as the positive electrode current collector 6, dried, and compressed by a roll press to a predetermined density. And the positive electrode plate 1 was produced by cut | disconnecting the aluminum foil in which the slurry was apply | coated to the predetermined size corresponding to a battery shape. The positive electrode plate 1 was provided with a portion where an electrode mixture was not applied for electrode terminal (tab) welding to form a positive electrode lead.

  Moreover, the negative electrode plate 2 was produced as follows. Powder obtained by mixing graphite as a conductive agent and polyvinylidene fluoride (PVDF) as a binder into non-graphitizable carbon is dispersed in N-methyl-2-pyrrolidone (NMP) to form a slurry. The conductor 12 was uniformly coated on both sides of a copper foil having a thickness of 10 [μm], dried, and then compressed by a roll press to a predetermined density. And the negative electrode plate 2 was produced by cut | disconnecting the copper foil with which the slurry was apply | coated to the predetermined size corresponding to a battery shape. As for the negative electrode plate 2, similarly to the positive electrode plate 1, an electrode mixture uncoated portion for tab welding was provided to form a negative electrode lead.

  Next, the positive electrode plate 1 and the negative electrode plate 2 are alternately laminated while sandwiching the separator 7 between the negative electrode plate 2 and the positive electrode plate 1 so that the negative electrode plate 2 is the outermost part, and the electrode laminate 18 Was made. The number of stacked electrode plates is set to a value that provides a predetermined battery capacity (for example, 2 [Ah]). As the separator 7, a microporous polyethylene film having a thickness of 25 [μm] was used.

  Further, a positive electrode tab 14 made of aluminum having a thickness of 100 [μm] was joined to the positive electrode plate group (positive electrode lead group) of the electrode laminate 18 by ultrasonic welding. Similarly, the negative electrode tab 15 made of nickel having a thickness of 100 [μm] was joined to the negative electrode plate group (negative electrode lead group) of the electrode laminate 18 by ultrasonic welding.

  Next, after welding what each welded the positive electrode tab 14 and the negative electrode tab 15 to the electrode group in a pair of laminate film 17, the total 3 sides of the short side 2 sides and the long side 1 side are heated around the film periphery. Welded with a seal. At this time, the pair of laminate films 17 has a cup shape provided with a recess to accommodate the electrode group. The size of the electrode stack 18 is 200 [mm] × width 120 [mm] × height 3 [mm], and the positive electrode tab 14 and the negative electrode tab 15 are led out from both sides of the short side, respectively. It was. The laminate film 17 is a nylon layer 23 with a thickness of 15 [μm] as a protective layer, an aluminum alloy layer with a thickness of 40 [μm] as a metal layer, and a polymer resin layer from the outside of the battery. The thing of the three-layer structure of the polypropylene resin layer of thickness 45 [micrometer] was used.

Next, after injecting the electrolyte solution from the opening of the laminate film 17 (the unwelded long side) and then reducing the pressure, the opening was welded to produce a battery. Here, as the electrolytic solution, a solution obtained by dissolving 1 [mol / liter] of LiPF ₆ as a supporting electrolyte in a mixed solvent of propylene carbonate, ethylene carbonate and diethyl carbonate was used.

  Next, the battery abnormality detection device and battery abnormality detection method of this embodiment will be described in detail with reference to FIG. FIG. 4 is an explanatory diagram for conceptually explaining an aspect in which a partial cross section of the laminate film 17 is enlarged and a battery abnormality is detected.

  Examples of defects in the inner surface resin layer (insulating layer; polypropylene resin layer 27) of the exterior material (laminate film 17) that are generated during the manufacture of the battery include pinholes, cracks, and scratches. As shown in FIG. 4, the electrolyte solution 8 inside the battery penetrates into the defective portion 30 generated in the polypropylene resin layer 27, and the electrolyte solution 8 comes into contact with the metal layer (aluminum alloy layer 25) of the laminate film 17. The insulation between the inside of the battery and the metal layer (aluminum alloy layer 25) of the laminate film 17 is lowered.

  In the battery abnormality detection device and battery abnormality detection method of this example, a DC voltage or an AC voltage is applied between the metal layer (aluminum alloy layer 25) of the laminate film 17 and one battery terminal (negative electrode tab 15), Based on the resistance value between the metal layer (aluminum alloy layer 25) of the laminate film 17 and one battery terminal (negative electrode tab 15) at that time, the presence or absence of a defect in the insulating layer (polypropylene resin layer 27) of the laminate film 17 is determined.

  Specifically, at the time of resistance measurement by the measuring instrument 41, one measurement terminal 42 (for example, a rod or a planar electrode or a clip-shaped terminal is used) is brought into contact with one battery terminal (the negative electrode tab 15), Further, the other measurement terminal 43 (for example, a needle-shaped terminal having a pointed end portion is used) is inserted into the aluminum alloy layer 25 of the laminate film 17 and measured. Note that the connection location of the measurement terminal 42 may be the positive electrode tab 14 instead of the negative electrode tab 15.

  Thereby, the defect of the insulating layer of the exterior material generated at the time of manufacture can be detected with a simple configuration and method without destroying the battery itself (electrode laminate 18). In order to increase the reliability of measurement, it is necessary to destroy a part of the battery (destruction by inserting the needle-shaped measurement terminal 43 into the aluminum alloy layer 25 of the laminate film 17 to penetrate it). By providing an extra film for inspection, it is also possible to cut the part destroyed after the inspection. However, in this case, there is a drawback that the manufacturing cost of the battery becomes high.

  Next, a specific application example will be described. In this application example, as a battery for evaluation, a non-defective product having a defect in the insulating layer of the exterior material and a defective product having a defect in the insulating layer of the exterior material are prepared, and a DC voltage (100 [V]) and The resistance value when an alternating voltage (1 [V], frequency 1 [kHz]) was applied was measured.

  Here, a non-defective product having no defect in the insulation layer of the exterior material was produced using the above-described production method, and a defective product having a defect in the insulation layer of the exterior material was previously provided with a defect in the polypropylene resin layer 27. It was produced using the production method described above except that the laminate film 17 was used as an exterior material. In addition, the defect of the insulating layer of the exterior material was a melting mark attached with a needle-like metal heated to a temperature higher than the melting point of the insulating layer, or a scratch physically attached with a sharp blade.

  The measured resistance value (average value of 5) when a DC voltage (100 [V]) is applied is 2000 [MΩ] or more for a non-defective product having no defect in the insulation layer of the exterior material. The non-defective product was 20 [MΩ]. In addition, the measured resistance value (average value of 5) when an AC voltage (1 [V], frequency 1 [kHz]) is applied is 300 [kΩ] for a non-defective product having no defect in the insulation layer of the exterior material. A defective product having a defect in the insulating layer had a resistance of 70 [kΩ]. In each case of the direct current voltage and the alternating current voltage, the difference in resistance value between the non-defective product and the defective product is large, and the presence or absence of a defect in the insulating layer of the laminate film 17 can be determined based on the measured resistance value.

  Furthermore, in this embodiment, the power source provided in the measuring instrument 41 is configured to include a DC power source or an AC power source. However, depending on the application, either one of the configuration including one or the configuration including both may be selected. good. Note that there is no difference in the effect whether a DC power supply or an AC power supply is used, but when a DC voltage is applied using a DC power supply, a relatively higher voltage is applied than when an AC voltage is applied. It is necessary to supply.

[Example 2]
FIG. 5 is an explanatory diagram conceptually illustrating an aspect when battery abnormality detection is performed using the battery abnormality detection device according to the second embodiment of the present invention.

  The abnormality detection target battery is a laminate type battery using a laminate film in which the surface of the metal layer is covered with an insulating layer as an exterior material. Reference numeral, structure, and manufacturing process of FIG. ) And the description is omitted.

  The measuring device 51 and the measuring terminals 52 and 53 are the battery abnormality detecting device according to the second embodiment. The measuring device 51 includes at least an alternating current between the surface of the laminate film 17 and one of the battery terminals (negative electrode tab 15). An AC power source for applying a voltage; resistance measuring means for measuring a resistance value between the surface of the laminate film 17 and one battery terminal (negative electrode tab 15) when the AC voltage is applied; and the laminate film 17 based on the measured resistance value. Defect presence / absence determining means for determining the presence / absence of a defect in the insulating layer.

  Next, the battery abnormality detection device and battery abnormality detection method of this embodiment will be described in detail with reference to FIG. FIG. 6 is an explanatory diagram for conceptually explaining an aspect in which a partial cross section of the laminate film 17 is enlarged and a battery abnormality is detected.

  In the battery abnormality detection device and battery abnormality detection method of the present embodiment, an AC voltage is applied between the surface of the laminate film 17 and one battery terminal (negative electrode tab 15), and the surface of the laminate film 17 at that time and one of the battery terminals are detected. The presence or absence of a defect in the insulating layer (polypropylene resin layer 27) of the laminate film 17 is determined based on the resistance value between the battery terminals (negative electrode tab 15).

  Specifically, at the time of resistance measurement by the measuring instrument 51, one measurement terminal 52 (for example, a rod or a planar electrode or a clip-shaped terminal is used) is brought into contact with one battery terminal (the negative electrode tab 15), Further, measurement is performed by bringing the other measurement terminal 53 (for example, using a planar electrode terminal) into contact with the surface of the laminate film 17. Note that the connection location of the measurement terminal 42 may be the positive electrode tab 14 instead of the negative electrode tab 15. In FIG. 5, the measurement terminal 53 is in contact with the lower surface of the laminate film 17, and in FIG. 6, the measurement terminal 53 is in contact with the upper surface of the laminate film 17.

  In Example 1, it was necessary to destroy a part of the battery (destruction by inserting the needle-shaped measurement terminal 43 into the aluminum alloy layer 25 of the laminate film 17 and penetrating it). Then, since an alternating voltage is applied, even if the voltage value is low, the resistance value can be measured only by bringing the measurement terminal 53 into contact with the surface of the laminate film 17, and the insulation layer of the exterior material generated at the time of manufacture can be measured. Defects can be detected with a simple configuration and method without destroying the battery.

  Note that it is possible to detect similar defects in the insulating layer even when a DC voltage is used. However, when applying a DC voltage, it is necessary to apply a larger voltage than when using AC, but when a high voltage is applied, for example, a metal layer and electrode terminals exposed in the cross section of the laminate film If the distance between the metal layer and the electrode terminal is close due to creeping discharge or the like, there is a possibility that defects in the insulating layer cannot be accurately detected. Is sufficiently secured (insulation between the metal layer of the laminate film and the electrode terminal is sufficiently secured).

  Next, a specific application example will be described. In this application example, as the evaluation battery, a plurality of non-defective products having a defect in the insulating layer of the outer packaging material and a defective product having a defect in the insulating layer of the outer packaging material are prepared, and an AC voltage (1 [V], frequency 1 [kHz]) was applied to measure the resistance value.

  Here, as in Example 1, a good product having no defect in the insulating layer of the exterior material is produced using the above-described production method, and a defective product having a defect in the insulating layer of the exterior material is preliminarily made of polypropylene resin. It produced using the preparation method mentioned above except having used the laminate film 17 which provided the defect in the layer 27 as an exterior material. In addition, the defect of the insulating layer of the exterior material was a melting mark attached with a needle-like metal heated to a temperature higher than the melting point of the insulating layer, or a scratch physically attached with a sharp blade.

  The measured resistance value (average value of 5) when an AC voltage (1 [V], frequency 1 [kHz]) is applied is 80 [MΩ] for a non-defective product having a defect in the insulation layer of the exterior material. It was 400 [kΩ] for defective products having defects. The difference in resistance value between the non-defective product and the defective product is large, and it is possible to determine the presence or absence of a defect in the insulating layer of the laminate film 17 based on the measured resistance value.

  In addition, in order to make the battery abnormality detection method in Example 1 and Example 2 a simpler method, a threshold value of a resistance value for determining the presence / absence of a defect is set in advance, and if it exceeds the threshold value, A method of determining a defective product if it falls below a threshold value can be considered. Since the resistance value is considered to vary depending on the type and shape of the defective portion 30 and the material of the battery component, etc., a defective product having various assumed defects may be used when setting the determination threshold. It is preferable to set a determination threshold value that is at least larger than the maximum resistance value of these defective products and that is as large as possible from the average value of non-defective products.

It is explanatory drawing which illustrates notionally the aspect at the time of performing battery abnormality detection using the battery abnormality detection apparatus which concerns on Example 1 of this invention. 2A is a plan view of the entire battery, and FIG. 2B is a cross-sectional view of the entire battery. 3 (a) is an enlarged cross-sectional view of part A of FIG. 2 (b), FIG. 3 (b) is an enlarged cross-sectional view of part B of FIG. 3 (a), and FIG. 3 (c) is a view of FIG. It is an expanded sectional view of the C section. It is explanatory drawing which illustrates more conceptually the aspect at the time of detecting the abnormality of a battery by carrying out enlarged display of the partial cross section of the laminate film. It is explanatory drawing which illustrates notionally the aspect at the time of performing battery abnormality detection using the battery abnormality detection apparatus which concerns on Example 2 of this invention. It is explanatory drawing which illustrates more conceptually the aspect at the time of detecting the abnormality of a battery by carrying out enlarged display of the partial cross section of the laminate film.

Explanation of symbols

1 Positive electrode plate (positive electrode active material, positive electrode conductive material, positive electrode binder)
6 Positive current collector 7 Separator 8 Electrolyte 2 Negative electrode plate (negative electrode active material, negative electrode conductive material, negative electrode binder)
DESCRIPTION OF SYMBOLS 12 Negative electrode collector 14 Positive electrode tab 15 Negative electrode tab 16 Polypropylene film 17 Laminate film 18 Electrode laminated body 23 Protective layer (nylon layer)
24 Adhesive layer 25 Metal layer (aluminum alloy layer)
27 Polymer resin layer (polypropylene resin layer; insulating layer)
30 Defective part 41, 51 Measuring instrument 42, 43, 52, 53 Measuring terminal

Claims (4)

The power generation element formed by laminating the positive electrode plate and the negative electrode plate and the electrolytic solution are sealed inside the exterior body using a laminate film in which the surface of the metal layer is covered with an insulating layer, and the power generation element is electrically A battery abnormality detection device in which electrode terminals of a positive electrode and a negative electrode connected to the outside are led out to the exterior body,
A power source for applying a voltage between the laminate film and one of the positive electrode and negative electrode terminals;
Resistance measuring means for measuring a resistance value between the laminate film and one electrode terminal at the time of voltage application;
Defect presence determination means for determining the presence or absence of defects in the insulating layer of the laminate film based on the measured resistance value;
A battery abnormality detection device comprising: The power generation element formed by laminating the positive electrode plate and the negative electrode plate and the electrolytic solution are sealed inside the exterior body using a laminate film in which the surface of the metal layer is covered with an insulating layer, and the power generation element is electrically A battery abnormality detection device in which electrode terminals of a positive electrode and a negative electrode connected to the outside are led out to the exterior body,
An AC power supply that applies an AC voltage between the surface of the laminate film and one of the positive electrode and negative electrode terminals,
Resistance measuring means for measuring a resistance value between the laminate film and one of the electrode terminals when an alternating voltage is applied;
Defect presence determination means for determining the presence or absence of defects in the insulating layer of the laminate film based on the measured resistance value;
A battery abnormality detection device comprising: The power generation element formed by laminating the positive electrode plate and the negative electrode plate and the electrolytic solution are sealed inside the exterior body using a laminate film in which the surface of the metal layer is covered with an insulating layer, and the power generation element is electrically A battery abnormality detection method in which positive and negative electrode terminals connected to the outside of the exterior body are led out,
A voltage is applied between the laminate film and one of the positive electrode and negative electrode terminals, and insulation of the laminate film is performed based on a resistance value between the laminate film and the one electrode terminal at that time. A method for detecting an abnormality of a battery, comprising determining whether or not a layer has a defect. The power generation element formed by laminating the positive electrode plate and the negative electrode plate and the electrolytic solution are sealed inside the exterior body using a laminate film in which the surface of the metal layer is covered with an insulating layer, and the power generation element is electrically A battery abnormality detection method in which positive and negative electrode terminals connected to the outside of the exterior body are led out,
An alternating voltage is applied between the surface of the laminate film and one of the positive electrode and negative electrode terminals, and based on the resistance value between the laminate film and one of the electrode terminals, A method for detecting an abnormality of a battery, characterized by determining the presence or absence of a defect in an insulating layer.

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