JP4819399B2 - Thin battery - Google Patents

Description

  The present invention relates to a thin battery in which a battery element is accommodated together with an electrolyte in a package made of a laminate film or the like.

  In recent years, as a driving power source for an electric vehicle or the like, an assembled battery including a plurality of thin batteries (for example, lithium ion secondary batteries) is used. In such an assembled battery, it is known that the battery (thin battery) needs to be cooled in order to maximize the charge / discharge performance of the battery (or in order not to shorten the battery life). It has been. A thin battery generally has a structure in which a battery element configured as a laminated body of metal foil is housed together with an electrolytic solution in a package made of a laminate film.

8 and 9 show the configuration of a conventional thin battery disclosed in Patent Document 1. FIG. The thin battery 350 includes a battery element 302 in which a positive electrode metal foil (not shown) and a negative electrode metal foil are alternately laminated via separators, and two laminate films 301 for accommodating the battery elements 302. Have. The two laminated films 301 are heat-sealed with each other at the four sides of the outer peripheral portion, and the electrode tab 302a is drawn out from one side. This thin battery 350 is characterized in that the laminate film 301 is formed in a wave shape, and thus, for example, the thin battery 350 can be bent in the direction of arrow A in FIG. .
JP 2000-173559 A

  When an assembled battery is configured using such a thin battery 350, for example, if the batteries are stacked as shown in FIG. 10, a gap is secured between the corrugated portions, and this is used as the ventilation path 370. It is thought that it is possible. According to this, since a ventilation path is ensured between batteries, without using a special spacer etc., it is advantageous at the point which can simplify the structure of an assembled battery.

  However, Patent Document 1 does not assume that the thin battery 350 is laminated in this way, and it is considered difficult to realize such lamination for the following reasons. That is, as shown in FIG. 11, in the thin battery of Patent Document 1, a cavity 304 is formed between the battery element 302 and the film 301, and the film is relatively easily deformed at this portion. Therefore, when laminated as shown in FIG. 10, the film may actually be crushed. In this case, the ventilation path 370 is not secured.

  As described above, if the corrugated portion formed on the film 301 is used, the ventilation path 370 can be secured without using a spacer or the like. However, in order to realize this, it is necessary to take some measures so that the film 301 is not deformed, that is, the air passage 370 is satisfactorily secured. Here, for example, a reinforcing member may be disposed in the hollow portion 304 to prevent the film from being deformed. However, this is not preferable because an unnecessary member is added.

  The present invention has been made in view of the above problems, and its purpose is to ensure the rigidity of the corrugated portion of the film without adding a special member, and to perform heat dissipation satisfactorily. It is an object to provide a thin battery that can be used.

  In order to achieve the above object, a thin battery according to the present invention is a thin battery in which a battery element configured to store and output electrical energy is housed together with an electrolyte in a film package. The cross-sectional shape is formed into a wave shape, and the film packaging body is formed with a wave shape portion having the same shape as the wave shape of the battery element so as to be along the outer peripheral surface of the battery element. And Further, in the present invention, the inside of the film packaging body may be in a vacuumed state, and the waveform of the battery element (the same as the waveform of the film) is a sine waveform or a trapezoidal waveform. It may be.

  According to the said invention, the battery element is made into the waveform cross section, and the waveform part of a film packaging body is formed so that the outer peripheral surface (surface) of the battery element may be met. That is, since the corrugated portion of the film package is formed without generating a cavity between the film and the battery element, the rigidity of the corrugated portion of the film is sufficiently ensured. In addition, since the cavity between the film and the battery element does not occur, heat dissipation is better than that of the conventional configuration (for details, see [Best Mode for Carrying Out the Invention] It will be described in the column of “form”] And according to the thin battery of this invention comprised in this way at the time of comprising an assembled battery, a ventilation path can be ensured between batteries, without requiring a special spacer.

  Another thin battery of the present invention includes two battery elements each configured to store and output electrical energy, a passage forming member disposed between the two battery elements, and the 2 A thin battery having one battery element and a film package housing the passage forming member, wherein the passage forming member has a plurality of cooling air passages extending through the film packaging body, The cross-sectional shape of each battery element is formed in a corrugated shape, and the film packaging body is formed with a corrugated portion having the same shape as the corrugated shape of the battery element, along the outer peripheral surface of the battery element. Yes.

  In this thin battery, two battery elements are arranged inside one film package. A passage forming member is disposed between the two battery elements, and this passage forming member functions as a reinforcing member or a cooling member for the battery element. Therefore, the rigidity of the battery as a whole is improved and the heat dissipation is also maintained well. In this thin battery as well, since the battery element has a wave shape and the film packaging body has a wave shape portion as in the above thin battery, the rigidity of the wave shape portion of the film is the same as above. Sufficiently secured and good heat dissipation.

  With respect to the other thin battery of the present invention, the passage forming member has a first surface and a second surface that face each of the battery elements, and each of the battery elements has one of the surfaces described above. It is preferable that they are arranged in close contact with the first surface or the second surface. This is because when the battery element is in close contact with the passage forming member, the heat of the battery element is transmitted to the passage forming member well, and as a result, the heat dissipation of the battery is further improved.

  More specifically, the film package is composed of two laminated films, and the vicinity of the portion where the cooling air passage opens of the passage forming member is formed by the two laminated films. It may be sandwiched. Moreover, it is preferable that the two battery elements have a symmetrical structure with respect to the passage forming member. The wave shape of each battery element may be a trapezoidal waveform, and the inside of the film package may be evacuated. In addition, the extending direction of each cooling air passage may coincide with the ridge line direction of the wave in the wave shape of the battery element.

  As described above, according to the thin battery of the present invention, the battery element has a corrugated cross section, and the corrugated portion of the film is formed along the surface of the battery element, so a special member is added. The rigidity of the corrugated portion of the film can be ensured without any problem. In addition, since no hollow portion is formed between the film and the battery element, the heat dissipation of the battery is also good.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a cross-sectional view showing the configuration of the thin battery of this embodiment. As shown in FIG. 1, the thin battery 50 basically has a film 24A, 24B (hereinafter also simply referred to as a film 24) constituting a film package and an electrolyte solution (non-conductive) in the film package, as in the conventional structure. The electrode tab 25 electrically connected to the internal battery element 22 is drawn out from the sealing part 26 which heat-sealed the films 24 with each other.

  The battery element 22 is formed by alternately stacking positive plates 23a and negative plates 23b via separators (not shown). In the present embodiment, the battery elements 22 are formed in a sine waveform cross-sectional shape. The thickness of the battery element 22 is, for example, about several mm to 10 mm. The material of each of the positive electrode plate 23a and the negative electrode plate 23b is not particularly limited as long as it is generally used.

  As an example, the positive electrode plate 23a includes a positive electrode active material such as a metal oxide, a conductive material such as carbon black, and an adhesive such as an aqueous dispersion of polytetrafluoroethylene in a polymerization ratio of, for example, 100: 3. : A mixture mixed at a ratio of 10 is applied to both surfaces of a metal foil (for example, an aluminum foil) as a positive electrode side current collector, dried, rolled, and then cut into a predetermined size. For example, the negative electrode plate 23b is prepared by mixing an aqueous dispersion of styrene butadiene rubber resin powder in a solid content ratio of, for example, 100: 5 to a negative electrode active material that absorbs and releases lithium ions of the positive electrode active material, and this mixture is mixed with the negative electrode side. The metal foil (for example, nickel foil or copper foil) as a current collector is coated on both sides, dried, rolled, and then cut into a predetermined size.

  Such positive electrode plates 23a and negative electrode plates 23b are alternately stacked via separators and pressed to obtain a battery element 22 having a wave shape. When packaging the battery element 22, it is preferable to heat-seal the two films 24A and 24B while evacuating. Thereby, the inside of a film packaging body will be in a vacuum state (it says the atmospheric pressure state lower than atmospheric pressure), and the inner surface of each film 24A, 24B will closely_contact | adhere to the outer peripheral surface of the battery element 22.

  It should be noted that the films 24A and 24B may be preliminarily provided with a wave shape by, for example, pressing. When the film is relatively soft, such pre-pressing is not necessary because the film adheres along the outer shape of the battery element when evacuation is performed.

  FIG. 2 shows an example in which an assembled battery is configured by superimposing thin batteries 50. The two thin batteries 50 are turned upside down so as to face each other so that the films 24B face each other, whereby the ventilation path 70 is formed between the trough portions of the corrugated portion. According to the configuration of the present embodiment, there is an advantage that the ventilation path 70 is formed without interposing a special spacer or the like between the batteries, but it is possible to use a spacer or the like if necessary. .

  The electrode tabs 25 can be joined together using, for example, laser welding. In view of the fact that the trough portion of the corrugated portion constitutes the ventilation path 70 in this way, the extending direction of the trough portion (that is, the ridge line of the wave) is, for example, straight in the short direction of the battery as in the conventional configuration. Preferably, the ventilation path 70 is also formed straight.

  In the thin battery 50 of the present embodiment, the battery element 22 has a corrugated cross section, and the film 24 is formed with a corrugated portion along the outer peripheral surface of the battery element 22. Therefore, unlike the conventional configuration, the cavity 304 (see FIG. 11) does not occur between the film and the battery element. According to such a configuration, rigidity is ensured in the corrugated portion of the film 24. Therefore, even if the batteries are overlapped as shown in FIG. 2, the film is not deformed, and the ventilation path 70 is excellent. It will be secured.

  Further, when the battery element 22 has a wave shape as in the present embodiment, the surface area of the positive electrode plate 23 and the negative electrode plate 24 can be increased without enlarging the outer shape of the battery element. It is also advantageous for output. Further, the configuration of the present embodiment is advantageous from the viewpoint of heat dissipation because the hollow portion 304 is not generated unlike the configuration of FIG. That is, in the configuration of FIG. 11, since there is the hollow portion 304, it is considered that heat exchange between the refrigerant (cooling air) sent into the ventilation path and the battery element is not efficiently performed. On the other hand, in the configuration of the present embodiment, since no hollow portion is generated, heat exchange between the refrigerant and the battery element 22 is favorably performed.

  Further, in the configuration of the present embodiment, since the battery element 22 has a corrugated cross section, even if an external force in the direction of arrow B in FIG. This is due to the improved rigidity of the battery element with respect to the wave ridgeline direction.

  Note that the shape of the corrugated portion (the depth of the valleys or the interval between the valleys) can be changed as appropriate. Further, the wave shape is not limited to a sine waveform, and for example, a rectangular waveform or a trapezoidal waveform may be continuous. Further, as a specific example of the films 24A and 24B, for example, a resin layer having heat melting property, a non-venting layer made of a metal thin film, and a protective layer made of nylon or the like are laminated in this order. A laminate film having a layer structure may be used.

(Second Embodiment)
An example of a thin battery in which the cross-sectional shape of the battery element has a trapezoidal waveform will be described with reference to FIGS. In addition, in the thin battery 150 shown in FIGS. 3-5, in addition to the cross section of a battery element being trapezoid wave shape, it becomes the structure by which two battery element 122A, 122B is arrange | positioned in one film packaging body. Yes. That is, the thin battery 150 has a so-called sandwich type structure in which two battery elements 122A and 122B are arranged so as to sandwich the passage forming member 130 therebetween.

  First, the basic concept of such a sandwich type structure will be described with reference to FIGS. In FIG. 6 and FIG. 7, each component is shown with a reference numeral different from that in FIGS. 3 to 5 in order to distinguish it from the component of the present embodiment.

  The thin battery 250 shown in FIGS. 6 and 7 has two battery elements 222A and 222B, and a flat passage forming member 230 disposed therebetween. One battery element outputs, for example, an electromotive force of about 3.6V, and in this configuration, since there are two of them, a double output (about 7.2V) can be obtained.

  The passage forming member 230 is a resin molded product, and has a plurality of cooling air passages 232 (height dimensions are about 1.5 to 2.0 mm, for example) partitioned by ribs. In the completed state of the thin battery, as shown in FIG. 7, both ends in the short direction of the passage forming member 230 are sandwiched between the sealing portions 226 of the film. Thus, the cooling air passage 232 is in a state of penetrating the film outer package without being blocked by the film. By sending cooling air into the cooling air passage 232, heat from the battery element is released to the outside.

  In the configuration in which the two battery elements 222A and 222B are simply stacked without using the passage forming member 230, heat easily accumulates in the battery elements, and problems due to the heat tend to occur. On the other hand, according to the sandwich type structure shown in FIGS. 6 and 7, since the cooling air passage 232 is secured between the battery elements, there is an advantage that heat radiation can be performed satisfactorily. Further, in this thin battery, since the passage forming member 230 also functions as a reinforcing member, there is an advantage that the rigidity of the thin battery as a whole is improved.

  Refer to FIG. 3 again. The thin battery 150 according to the present embodiment is obtained by corrugating the cross-sectional shape of the battery element while maintaining the advantages of such a sandwich structure. That is, battery elements 122A and 122B are arranged instead of the battery elements 222A and 222B of FIG. 6, and a passage forming member 130 having a plurality of cooling air passages 132 is arranged instead of the passage forming member 230.

  Each of the battery elements 122A and 122B has the same configuration, and the cross-sectional shape thereof is a trapezoidal wave shape. The positive electrode plate 123a and the negative electrode plate 123b constituting each battery element can be the same as the positive electrode plate 23a and the negative electrode plate 23b of the first embodiment.

  The two battery elements 122A and 122B have a symmetric structure with respect to the passage forming member 130. On the opposite side of the peak part 127 of one battery element, the peak part 127 of the other battery element exists. ing. In each peak portion 127, the surface of the film is flat so that the batteries can be satisfactorily overlapped.

  FIG. 4 shows an example in which an assembled battery is configured by superimposing thin batteries 150. By stacking the two thin batteries 150 so that the peak portions 127 of each battery are in contact with each other, an air passage 170 having a hexagonal cross section is formed between the valleys of the corrugated portions. The ventilation path 170 extends in the same direction as the cooling air passage 132, and the opening of the ventilation path 170 and the opening of the cooling air passage 132 both face the same direction. According to such a structure, there exists an advantage that it is easy to comprise the duct (not shown) for sending cooling air into each channel | path 132,170.

  FIG. 5 shows an enlarged part of the side edge of the thin battery 150. As shown in the drawing, the passage forming member 130 is sandwiched between two films 124A and 124B in the vicinity of a portion where the cooling air passage 132 is opened. In this case, the inner surface of each film may be joined to the outer peripheral surface of the passage forming member by heat sealing, for example. Or the inner surface of a film and the outer peripheral surface of a channel | path formation member may be joined in the state which interposed the adhesive agent etc.

  According to the present embodiment described above, advantages similar to those of the first embodiment can be obtained because the battery elements 122A and 122B have a wave shape. Further, since the thin battery 150 has a sandwich structure in which two battery elements are arranged so as to sandwich the passage forming member, an output equivalent to two battery elements can be obtained without impairing heat dissipation and rigidity. It is like that.

  From the viewpoint of favorably dissipating heat from the battery element, it is preferable that the lower surface of the battery element 122A and the upper surface (first surface) of the passage forming member 130 are in close contact with each other. That is, it is preferable that the lower surface of the battery element and the upper surface of the passage forming member have a complementary shape. The same applies to the relationship between the upper surface of the battery element 122B and the lower surface (second surface) of the passage forming member 130. As described above, since the battery element and the passage forming member are in close contact with each other, the heat of the battery element is favorably transmitted to the passage forming member. The heat transmitted to the passage forming member is exchanged with the refrigerant (cooling air) sent into the cooling air passage 132 and released to the outside.

  The interval between the cooling air passages 132 in the passage forming member 130 is not particularly limited, but the cooling air passages 132 are preferably arranged at equal intervals. Thereby, the cooling with respect to a battery element becomes uniform. The passage forming member 130 is not limited to a resin molded product, and for example, two insulating plate members may be arranged to face each other. If an example of a specific material is given, this plate member may be obtained by coating an electrically insulating material on a heat good conductor such as metal. By using a good heat conductor such as a metal, heat exchange between the refrigerant in the cooling air passage 132 and the battery element can be performed satisfactorily.

  As described above, the present invention has been described by taking two embodiments as examples. However, the configurations of the embodiments may be used in combination with each other. For example, in the configuration of the second embodiment, the waveform of the battery element can be a sine waveform.

It is sectional drawing which shows the structure of the thin battery which concerns on 1st Embodiment. It is a figure which shows the example which comprised the thin battery of FIG. It is sectional drawing which shows the structure of the thin battery which concerns on 2nd Embodiment. It is a figure which shows the example which comprised the thin battery of FIG. 3 on which the assembled battery was comprised. It is a perspective view which expands and partially shows the side edge part of the thin battery of FIG. It is a disassembled perspective view for demonstrating the basic structure of the thin battery which concerns on 2nd Embodiment. It is an external appearance perspective view which shows the completion state of the thin battery of FIG. It is an external appearance perspective view which shows the structure of the conventional thin battery. It is a disassembled perspective view which shows the structure of the thin battery of FIG. It is a figure which shows the example which comprised the conventional thin battery and overlapped and comprised the assembled battery. It is sectional drawing which shows the internal structure of the thin battery of FIG.

Explanation of symbols

22, 122A, 122B Battery element 23a, 123a Positive electrode plate 23b, 123b Negative electrode plate 24A, 24B, 124A, 124B Film 25, 125 Electrode tab 26 Sealing portion 127 Mountain portion 130 Passage forming member 132 Cooling air passage 50, 150 Thin battery 70, 170 Ventilation path

Claims (6)

Two battery elements each configured to store and output electrical energy, a passage forming member disposed between the two battery elements, and the two battery elements and the passage forming member are accommodated. A thin battery having a film package,
The passage forming member has a plurality of cooling air passages extending in a state of penetrating the film packaging body, and each battery element has a corrugated cross-sectional shape. A thin battery in which a corrugated portion having the same shape as the corrugated shape of the battery element is formed along the outer peripheral surface of the battery. The passage forming member has a first surface and a second surface facing each of the battery elements, and each of the battery elements has one surface on the first surface or the second surface. The thin battery according to claim 1 , wherein the thin battery is arranged in close contact. The film package can be comprised of two laminated films, near the site where the passage forming member, said cooling air passage is opened is sandwiched by the two laminated films, according to claim 1 Or the thin battery of 2 . It said two battery elements, wherein has the structure symmetrical with each other during the passage forming member, thin battery according to any one of claims 1 to 3. The corrugated each battery element is a trapezoidal waveform, the interior of the film package is in a state of being evacuated, thin battery according to any one of claims 1 to 4. The extending direction of the cooling air passages, the match in the ridge line direction of the wave in the battery element of the wave-shaped, thin battery according to any one of claims 1 to 5.

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