JP5784978B2 - Non-aqueous electrolyte battery - Google Patents

Description

  The present invention relates to a non-aqueous electrolyte battery.

  In a non-aqueous electrolyte battery, in order to achieve the purpose of extracting a large current instantaneously, that is, the purpose of obtaining a high output, a current path (path) from the electrode to the terminal portion is efficiently extracted from the electrode. It is effective to reduce the electrical resistance at the time of discharge by shortening.

  In Patent Document 1, a positive electrode tab of a wound flat electrode group is joined to a flat plate current collector fixed to a core, and a negative electrode tab of the wound flat electrode group is provided. Also disclosed is a flat secondary battery having a structure joined to a flat-plate negative electrode current collector fixed to a core on the opposite side of the positive electrode current collector.

JP 2010-146872 A

  In a nonaqueous electrolyte battery, when the battery is in an abnormal state, such as when the positive electrode and the negative electrode are short-circuited, gas may be generated inside the battery, and the internal pressure of the battery may increase abnormally. Since an abnormal increase in internal pressure is undesirable for the battery, a gas release valve for releasing gas to the outside of the battery is installed.

  In the configuration described in Patent Document 1, since the plate-like portion of the current collector is arranged in a direction intersecting with the winding axis of the electrode winding group, the path for discharging the gas inside the battery to the outside is narrowed. There was a problem that the gas release function was lowered.

  An object of the present invention is to provide a non-aqueous electrolyte battery excellent in safety by securing a path for releasing gas inside the battery to the outside when the internal pressure of the battery abnormally increases.

  In the nonaqueous electrolyte battery of the present invention, each of the positive electrode and the negative electrode has an exposed portion of a metal foil that is a substrate thereof, and the positive electrode current collector electrically connects the exposed portion to a flat portion thereof. The positive electrode external terminal is connected, and the negative electrode current collector has the negative electrode external terminal electrically connected to the exposed portion of the negative electrode current collector, and the positive electrode current collector And at least one of the negative electrode current collectors is disposed in a direction along a winding axis direction of the electrode winding group, and the planar part is disposed in a direction along the winding axis direction. A gas discharge valve is provided in a portion covering the positive electrode current collector or the negative electrode current collector having the above.

  ADVANTAGE OF THE INVENTION According to this invention, when the internal pressure of a battery rises abnormally, the path | route which discharge | releases the gas inside a battery outside can be ensured, and the nonaqueous electrolyte battery excellent in safety can be provided.

It is a partial expanded view which shows the winding group of the nonaqueous electrolyte battery of an Example. It is a fragmentary perspective view which shows the structure of the current collecting plate in the nonaqueous electrolyte battery of an Example, and a core. It is a perspective view which shows the structure of the nonaqueous electrolyte battery of an Example. It is an external appearance perspective view which shows the nonaqueous electrolyte battery of an Example. It is a fragmentary perspective view which shows the assembly procedure of the current collecting plate in the nonaqueous electrolyte battery of a comparative example, and a core. It is a fragmentary perspective view which shows the assembly procedure of the current collecting plate in the nonaqueous electrolyte battery of a comparative example, and a core. It is a perspective view which shows the structure of the nonaqueous electrolyte battery of a comparative example. It is a fragmentary perspective view which shows the assembly procedure of the current collecting plate in the nonaqueous electrolyte battery of an Example, and a core. It is a fragmentary perspective view which shows the assembly procedure of the current collecting plate in the nonaqueous electrolyte battery of an Example, and a core. It is a perspective view which shows the structure of the nonaqueous electrolyte battery of an Example.

  The present invention relates to a high-power and large-capacity non-aqueous electrolyte battery used for in-vehicle applications and the like, and more particularly to a flat and square flat wound lithium ion battery.

  Hereinafter, a nonaqueous electrolyte battery according to an embodiment of the present invention will be described.

  The non-aqueous electrolyte battery includes an electrode winding group in which a separator is wound between a positive electrode and a negative electrode, a positive electrode current collector, a negative electrode current collector, and a battery case storing these, And the negative electrode each have an exposed portion of a metal foil that is a substrate thereof, the positive electrode current collector is electrically connected to the flat portion, and the positive electrode external terminal is electrically connected The negative electrode current collector is electrically connected to the exposed portion of the negative electrode current collector, and the negative electrode external terminal is electrically connected to the flat surface portion of the positive electrode current collector and the negative electrode current collector. At least one of the planar portions is disposed in a direction along the winding axis direction of the electrode winding group, and has a planar portion disposed in the direction along the winding axis direction. A gas discharge valve is provided at a portion covering the part.

  In the non-aqueous electrolyte battery, the exposed portion is arranged in a direction along the flat portion.

  In the nonaqueous electrolyte battery, the joint between the flat portion and the exposed portion is disposed in a direction along the winding axis direction.

  In the non-aqueous electrolyte battery, the electrode winding group has a core, and the positive electrode current collector and the negative electrode current collector are fixed to the core.

  In the nonaqueous electrolyte battery, it is preferable that an area of a cross section orthogonal to the winding axis direction of at least one of the positive electrode current collector and the negative electrode current collector is smaller than the area of the gas release valve.

  In the non-aqueous electrolyte battery, it is preferable that the thickness of at least one of the positive electrode current collector and the negative electrode current collector is equal to or less than the thickness of the core.

  In the nonaqueous electrolyte battery, the gas release valve is provided at the bottom of at least one of the battery cases located on the end side in the winding axis direction of the electrode winding group.

  In the non-aqueous electrolyte battery, the exposed portion forms a tab group.

  In the non-aqueous electrolyte battery, at least one of the positive electrode external terminal and the negative electrode external terminal is installed at an end portion of the flat portion.

  In the nonaqueous electrolyte battery, the battery case has a flat shape.

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

  FIG. 1 shows a configuration of an electrode winding group applied to a nonaqueous electrolyte battery.

  In this figure, the wound group 102 (electrode wound group) has a configuration in which a separator 403 is sandwiched between a positive electrode plate 401 (positive electrode) and a negative electrode plate 402 (negative electrode) and wound around a core 404. . The positive electrode plate 401 is obtained by applying a positive electrode mixture on both surfaces of an aluminum foil. The negative electrode plate 402 is obtained by applying a negative electrode mixture on both surfaces of a copper foil. The separator 403 is made of polyolefin.

  At one end of the positive electrode plate 401, the aluminum foil is exposed without applying the positive electrode mixture. A strip-shaped positive electrode tab group 405 is formed at the end. On the other hand, the copper foil is exposed at the end of the negative electrode plate 402 without applying the negative electrode mixture. A strip-shaped negative electrode tab group 406 is formed at the end. The dimensions of the individual tabs of the positive electrode tab group 405 and the negative electrode tab group 406 are preferably 2 mm to 10 mm in width and 15 mm to 50 mm in length. The positive electrode tab group 405 protrudes from one end of the wound group 102, and the negative electrode tab group 406 protrudes from the other end. Here, the positive electrode tab group 405 and the negative electrode tab group 406 are also referred to as exposed portions of metal foil.

  FIG. 2 shows a schematic diagram of the joint between the electrode (positive electrode) and the current collector.

  In this figure, the positive electrode current collector 104 is a plate-like body having a flat surface portion 121, a positive electrode terminal 109 (positive electrode external terminal) is connected to the flat surface portion 121, and an opening provided at the end of the core 404. Two protrusions 106 for fitting into the portion 407 (groove portion) are arranged. The positive electrode current collector 104 is a plate member made of aluminum having a thickness of 0.5 to 5 mm. The length of the positive electrode current collector 104 may be arbitrarily determined according to the shape of the battery, but by making it larger than the opening size of the gas release valve, the contents are discharged together with the positive electrode current collector 104 to the outside. There is also an effect to prevent. Further, the positive electrode current collector 104 preferably has a cross-sectional area perpendicular to the winding axis direction smaller than the area of the gas release valve at any position in the winding axis direction. Furthermore, the thickness of the positive electrode current collector 104 is desirably equal to or less than the thickness of the planar portion 121 at any position in the winding axis direction including the protrusion 106. Furthermore, the thickness of the positive electrode current collector 104 is desirably equal to or less than the thickness of the core 404.

  A positive electrode tab group 405 is welded to the positive electrode current collector 104. The larger the area of the welded part (referred to as “welded part” or “joint part”), the better. This is because it contributes to a reduction in internal resistance when a large current flows.

  The protrusion 106 is fitted and fixed to the opening 407 of the core 404 wound around the winding group 102. A current collector (negative electrode current collector) is similarly formed on the negative electrode side. Note that the positive electrode current collector 104 and the negative electrode current collector are collectively referred to as an “electrode current collector”. Further, the shape of the positive electrode current collector 104 shown in this embodiment is referred to as an I-shape. This is because the shape of the positive electrode current collector 104 in the cross section perpendicular to the flat surface 121 of the core 404 is I-shaped.

  The positive electrode terminal 109 is desirably installed on the end of the flat surface portion 121 of the positive electrode current collector 104, that is, on a surface orthogonal to the winding axis direction. The same applies to the negative electrode terminal, and it is desirable to install the negative electrode terminal on the end of the flat surface of the negative electrode current collector, that is, on the surface orthogonal to the winding axis direction.

  FIG. 3 is a perspective view showing the configuration of the assembled nonaqueous electrolyte battery.

  In this figure, the nonaqueous electrolyte battery 100 has a configuration in which a wound group 102 (electrode wound group) to which a positive electrode current collector 104 and a negative electrode current collector 105 are attached is sealed in a battery case 101. A positive electrode side sealing plate 116 and a negative electrode side sealing plate 103 are arranged at both ends of the battery case 101. A positive electrode tab group 405 is welded to the positive electrode current collector 104. In this figure, the battery case 101 is composed of only the side surface (body), and both bottoms are open. However, one bottom of the battery case 101 is a closed surface, and the sealing plate 116 or sealing The structure which does not use either of the board 103 may be sufficient. These are fixed by welding with an electron beam or a laser.

  The positive electrode terminal 109 (positive electrode external terminal) is installed so as to penetrate through the sealing plate 103 on the positive electrode side. The negative electrode terminal 110 (negative electrode external terminal) is installed so as to penetrate the negative electrode side sealing plate 116. The sealing plates 103 and 116 are provided with gas release valves 108 (cleavage valves). As shown in the figure, the gas release valve 108 is desirably provided on the sealing plates 103 and 116 orthogonal to the winding axis direction.

  Furthermore, the sealing plate 103 on the positive electrode side is provided with a liquid injection hole for injecting an electrolytic solution, and the liquid injection hole is sealed with a liquid injection stopper 107. Between the positive electrode terminal 109 and the sealing plate 103, an insulating cover 111 made by resin molding is provided. Similarly, an insulating cover 111 is provided between the negative electrode terminal 110 and the sealing plate 116.

  The positive terminal 109 and the negative terminal 110 are fixed by resin gaskets 112 and 115 and a nut 113. The positive terminal 109 and the negative terminal 110 are also collectively referred to as “external terminals”.

  The non-aqueous electrolyte battery of this example was designated as battery A1.

  The core 404 is produced by resin molding. If it is a thermoplastic resin, polypropylene or polyphenylene sulfide is used, and if it is a thermosetting resin, phenol resin, melamine resin, unsaturated polyester, etc. are used, it is particularly limited if it is a resin with high heat durability. It is not something. The insulating cover 111 and the two types of gaskets 112 and 115 are preferably manufactured by resin molding. If it is a thermoplastic resin, polypropylene or polyphenylene sulfide is used. If it is a thermosetting resin, phenol resin, melamine resin, unsaturated polyester, etc. are used. It is not limited.

  Moreover, although the separator 403 was described as being made of polyolefin in the examples, specifically, those made of polyethylene or polypropylene can be used alone or in combination. Furthermore, various ceramics and heat-resistant materials can be additionally used.

  FIG. 4 shows the appearance of the assembled battery.

  In this figure, a sealing plate 103 welded to a battery case 101 of a non-aqueous electrolyte battery 100 is provided with a liquid injection plug 107 and a gas release valve 108. The positive terminal 109 protrudes from the sealing plate 103 and is fixed with a nut 113.

  The rated capacity of this nonaqueous electrolyte battery 100 is 14 Ah.

(Comparative example)
5A and 5B show an example of a conventional configuration of the joint portion between the electrode winding group and the positive electrode current collector. This was used as a comparative example.

  FIG. 5A shows an arrangement when the positive electrode tab group is bonded to the positive electrode current collector, and FIG. 5B shows an arrangement when the positive electrode current collector is fitted to the core after bonding. Is.

  This battery is provided with a gas release valve on both end faces of the battery case. The wound group 102 is the same as that in the first embodiment.

  The positive electrode current collector 204 is a plate-like body having a current collector plate convex portion 603 (protrusion) on the flat surface portion 221, and the shape of the flat surface portion 221 is similar to the cross-sectional shape perpendicular to the winding axis. Moreover, the core 404 is also a flat plate shape, and its end is exposed at the end surface of the wound group 102.

  In the positive electrode current collector 204, the outer shape of the flat surface portion 221 is smaller than the outer shape of the oval end surface portion of the wound group 102 and larger than the outer shape of the end surface portion of the core 404. The positive electrode current collector 204 has a thickness of 0.5 to 5 mm and is a substantially oval plate. The positive electrode current collector 204 is provided with a positive electrode terminal 109. Further, the positive electrode current collector 204 is provided with an opening 602.

  When joining the positive electrode tab group 405 to the positive electrode current collector part 204, as shown in FIG. 5A, the positive electrode current collector part 204 is arranged in parallel with the flat surface part of the wound group 102 (core 404). The group 405 is pressed against the tab welded portion 601 on the back surface of the positive electrode current collector 204 and welded in close contact.

  Next, as shown in FIG. 5B, the positive electrode current collector 204 is disposed perpendicularly to the flat surface of the wound group 102 (core 404), and the current collector plate convex portion 603 of the positive electrode current collector 204 is It fits into the opening 407 of the core 404. As a result, the positive electrode current collector 204 is fixed to the core 404. Here, the shape of the positive electrode current collector 204 shown in this comparative example is referred to as a T-shape. This is because the shape of the positive electrode current collector 204 in the cross section perpendicular to the flat portion of the core 404 is T-shaped including the current collector plate protrusion 603.

  5A and 5B, the positive electrode tab group 405 is illustrated as being longer than the actual one for the sake of explanation, but it is sufficient if there is a margin for fitting the current collector plate projection 603 to the opening 407. It may be shorter than that shown.

  The junction between the electrode winding group and the negative electrode current collector is also configured in the same manner as in the case of the positive electrode.

  FIG. 6 shows a perspective view of the battery of this comparative example. Except for the configuration shown in FIGS. 5A and 5B, the second embodiment is the same as the first embodiment, and a detailed description thereof is omitted. For the positive electrode current collector 204 and the negative electrode current collector 205, a cross section in the thickness direction is shown. The gas release valve 108 is provided on the sealing plates 103 and 116 (on both sides).

  The non-aqueous electrolyte battery of this comparative example was designated as battery B1.

  A non-aqueous electrolyte battery was prepared in the same manner as in Example 1 except that the same winding group as in Example 1 was used, and the positive electrode current collector of Example 1 and the negative electrode current collector of Comparative Example were used. Assembled. This battery was provided with a gas release valve only on the end face where the positive electrode terminal of the battery case was arranged.

  The nonaqueous electrolyte battery of this example was designated as battery A2.

  A non-aqueous electrolyte battery was used in the same manner as in Example 1 except that the same winding group as in Example 1 was used and the positive electrode current collector part of Comparative Example and the negative electrode current collector part of Example 1 were used. Assembled. This battery was provided with gas release valves on both end faces of the battery case.

  The nonaqueous electrolyte battery of this example was designated as battery A3.

  7A and 7B show a modified embodiment of the joint portion between the electrode winding group and the positive electrode current collector.

  FIG. 7A shows the arrangement before joining the exposed metal foil portion of the positive electrode to the positive electrode current collector (before fitting the positive electrode current collector to the core), and FIG. The arrangement is shown.

  7A, the positive electrode current collector 104 has the same configuration as that in FIG. That is, the positive electrode current collector 104 is a plate-like body having a flat surface portion 121, a positive electrode terminal 109 (positive electrode external terminal) is connected to the flat surface portion 121, and an opening 407 provided at the end portion of the core. Two protrusions 106 for fitting are arranged.

  On the other hand, a metal foil exposed portion 1101 in which a metal foil (aluminum foil) that is a substrate of the positive electrode is exposed is provided at the end of the wound group 202 on the positive electrode current collector 104 side. A strip-shaped positive electrode tab group is not provided.

  Similarly, although not shown, a metal foil exposed portion where a metal foil (copper foil) as a negative electrode substrate is exposed is provided at the end of the wound group 202 on the negative electrode current collector side. A strip-shaped negative electrode tab group is not provided.

  7B, the positive electrode current collector 104 is fitted into an opening 407 provided at the end of the core 404 shown in FIG. 7A, and a part of the metal foil exposed portion 1101 is a tab of the positive electrode current collector 104. The welded portion 701 is pressed and welded in close contact.

  About the structure of those other than this, it carried out similarly to Example 1, and assembled the battery.

  In addition, since it is the same as that of Example 1 also in a negative electrode current collection part, detailed description is abbreviate | omitted.

  FIG. 8 shows a perspective view of the nonaqueous electrolyte battery of this example. Since the entire configuration is the same as that of the other embodiments, detailed description is omitted. The gas release valve 108 is provided on the sealing plates 103 and 116 (on both sides).

  The non-aqueous electrolyte battery of this example was designated as battery A4.

  In this embodiment, the positive electrode metal foil exposed portion 1101 is welded to one side of the positive electrode current collector 104 and the negative electrode metal foil exposed portion 1102 is welded to one side of the negative electrode current collector 105. Metal foil exposed portions 1101 and 1102 may be welded to both sides of the portion 104 and the negative electrode current collector portion 105. In that case, the gas emission path can be expanded by removing the unwelded portion of the exposed metal foil portion 1101 shown in FIG.

  Using the batteries A1 to A4 and B1, the battery was charged at a current value of 14A until the cell voltage reached 4.2V, and then the constant voltage charging of 4.2V was performed for 1.5 hours in the total charging time. . Thereafter, for the purpose of measuring the gas discharging ability from the battery, a steel nail having a diameter of 3 mm was passed through the flat battery approximately at the center at a speed of 2 to 80 mm / sec. At this time, since the steel nail short-circuits the positive electrode and the negative electrode, a large current flows, the Joule heat causes the temperature of the battery to rise, the generation of gas due to the decomposition or evaporation of the electrolyte, etc. Rises. As a result, when the gas release valve is activated, the gas is released.

  Table 1 shows the test results.

  The configuration of the battery described in this table relates to an electrode current collector (a positive electrode current collector and a negative electrode current collector) and a gas release valve, and this is a factor affecting performance. Here, “two I-shaped” and “two T-shaped” are cases where the shapes of the positive current collector and the negative current collector are the same. “One I-shaped, one T-shaped” is a case where the shapes of the positive current collector and the negative current collector are different. “No tab group” is shown in FIGS. 7A and 7B. Further, when the number of gas release valves is “2”, the gas release valves are provided on the sealing plates on both sides, and when the number of gas release valves is “1”, the gas release valve is provided on the one side of the sealing plates.

  The determination was “PASS” when the temperature of the battery was increased and gas was released due to the release of the gas release valve, and “FAIL” when the other phenomenon occurred.

  When the penetration speed of the nail was 2 mm / second, the battery temperature increased, the gas release valve was released, and the gas was released (PASS) in any battery. On the other hand, when the penetration speed of the nail was increased, an abnormal phenomenon was observed in the comparative battery B1 (FAIL).

  Compared to the current collector that covers the current collector side of the electrode winding group (the discharge passage of the gas generated inside the electrode winding group) as in the comparative example, the current collector of the example is The ratio of blocking the gas discharge passage is small. Therefore, in the current collection part of an Example, the resistance part of the gas between an electrode winding group and a gas discharge valve is only a current collection part and the welding part of the tab group of an electrode, or a metal foil exposed part.

  In addition, the example is easier to weld and easier to manufacture than the comparative example.

  Furthermore, in the case of a cylindrical battery, an O-shaped current collector disposed at the end of the battery case is conventionally used, but the current collector of the embodiment is welded more than the O-shaped current collector. Easy to do and lightweight.

  As described above, the batteries of the examples are excellent in safety, easy to manufacture, and lightweight.

  100: non-aqueous electrolyte battery, 101: battery case, 102: wound group, 103: sealing plate, 104: positive electrode current collector, 105: negative electrode current collector, 106: protrusion, 107: injection plug, 108 : Gas release valve, 109: Positive electrode terminal, 110: Negative electrode terminal, 111: Insulation cover, 112: Gasket, 113: Nut, 115: Gasket, 116: Sealing plate, 121: Flat part, 202: Winding group, 204: Positive electrode current collector, 205: Negative electrode current collector, 221: Plane portion, 301: Injection hole, 302: Gas discharge opening, 401: Positive electrode plate, 402: Negative electrode plate, 403: Separator, 404: Core 405: Positive electrode tab group, 406: Negative electrode tab group, 407: Opening part, 601: Tab weld part, 602: Opening part, 603: Current collector convex part, 1101: Metal foil exposed part, 1102: Metal foil exposed part.

Claims (8)

  An electrode winding group in which a separator is wound between a positive electrode and a negative electrode, a positive electrode current collector, a negative electrode current collector, and a battery case containing these, each of the positive electrode and the negative electrode, The exposed portion of the metal foil that is the substrate, the positive electrode current collector is electrically connected to the exposed portion on the flat surface, and the positive electrode external terminal is electrically connected The negative electrode current collector is electrically connected to the exposed portion of the negative electrode current collector, and is electrically connected to a negative electrode external terminal; the positive electrode current collector and the negative electrode current collector At least one of the planar portions is disposed in a direction along the winding axis direction of the electrode winding group, and the positive electrode assembly has the planar portion disposed in the direction along the winding axis direction. A gas discharge valve is provided in a portion covering the electric part or the negative electrode current collector, and the exposed part , Yes disposed in a direction along the planar portion, the junction between the exposed portion and the flat portion, the non-aqueous electrolyte battery, characterized in that is arranged in the direction along the winding axis direction.   The non-aqueous electrolyte battery according to claim 1, wherein the electrode winding group has a core, and the positive electrode current collector and the negative electrode current collector are fixed to the core.   The area of the cross section orthogonal to the winding axis direction of at least one of the positive electrode current collector and the negative electrode current collector is smaller than the area of the gas release valve. Non-aqueous electrolyte battery. 3. The nonaqueous electrolyte battery according to claim 2 , wherein a thickness of at least one of the positive electrode current collector and the negative electrode current collector is equal to or less than a thickness of the core.   The said gas release valve is provided in the bottom part of at least one of the said battery case located in the edge part side of the winding axis direction of the said electrode winding group, The any one of Claims 1-4 characterized by the above-mentioned. The non-aqueous electrolyte battery described in 1.   The non-aqueous electrolyte battery according to claim 1, wherein the exposed portion forms a tab group.   7. The nonaqueous electrolyte battery according to claim 1, wherein at least one of the positive electrode external terminal and the negative electrode external terminal is installed at an end portion of the flat portion.   The non-aqueous electrolyte battery according to claim 1, wherein the battery case has a flat shape.

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