JP2012209177A - Battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a sealant applied to a gasket enters a small gap between a PTC element and a cap because it has fluidity, to cause electrical connection failure in a sealing plate of a cylindrical battery, during preservation period at a high temperature for extended period or under an environment with accompanies abrupt temperature change.SOLUTION: A cap 9 containing a protruding part 15 on the side of contacting surface to a PTC element 10 is used to sandwich from both sides the PTC element 10 with an outer peripheral folding-back part 16 of a filter at the time of constituting a sealing plate for the battery. With this configuration, the electrical connection is assured at a sealing member in a sealing plate 6. Even in the case where a sealant 14 is softened under a high temperature environment or the like to enhance fluidity, entering into the gap is prevented, and the battery can include a stable internal resistance.

Description

  The present invention relates to a battery in which internal resistance is stabilized by improving a sealing plate.

  A lithium manganese dioxide battery using lithium metal or lithium alloy as a negative electrode active material and manganese dioxide as a positive electrode active material has high voltage and high energy density, low self-discharge, and extremely long shelf life. Since it has various features not found in primary batteries, demand has rapidly increased in recent years, and it is used in many electronic devices. The operating temperature range of the lithium manganese dioxide battery is wide from 70 ° C. to −40 ° C., and therefore it is widely used mainly as a film-type camera battery. Recently, it has been demanded that it is used for applications that require a wide use temperature range from 85 ° C. to −40 ° C. in automobiles, industrial equipment, medical equipment and the like by taking advantage of excellent performance.

  Not only a lithium primary battery but also a battery using an organic electrolyte is important for hermeticity. If the battery is not sufficiently sealed, there is a concern that the storage characteristics may deteriorate due to leakage of the organic electrolyte from the inside of the battery or moisture from the outside to the inside of the battery.

  The sealing plate of the cylindrical battery includes a sealing plate member in which a cap, a PTC (Positive Temperature Coefficient) element, a spacer and a filter attached with an aluminum valve body are sequentially laminated, and a gasket incorporated in the outer peripheral portion of the sealing plate member. Some are formed of a sealant applied to the surface where the gasket and the sealing plate member are in contact with each other. A sealing agent is also applied to the sealing plate between the gasket and the battery case. By applying a sealing agent to these two locations, the sealing plate member and gasket after sealing, and the gap between the gasket and battery case are filled with the sealing agent, preventing leakage from the sealing site. (See, for example, Patent Document 1).

  As the sealant, a material in which bron asphalt called pitch is dissolved in mineral oil, or an insulating material having excellent adhesion to a gasket such as butyl rubber and a sealing plate member is used.

  In such a sealing plate, for example, a PTC element and a cap have a fluidity because the sealant applied to the gasket has fluidity during a severe heat shock test with a rapid temperature change or during storage at a high temperature for a long time. There was a possibility that the sealing agent, which is an insulating material, may enter a slight gap therebetween. When a sealing agent that is an insulating material enters the gap between the PTC element and the cap, the contact resistance between the sealing plate members increases, and as a result, there is a problem that the internal resistance of the battery may increase. It was.

  For the above-mentioned problems, as a prior art, a structure in which a protrusion is provided on the inner gasket and a sealant is applied to a specific location to prevent the sealant from entering (for example, see Patent Document 2), a cap A device is disclosed in which a conductive adhesive is applied between PTC elements or between PTC elements and a filter to ensure electrical connection (see, for example, Patent Document 3).

JP 2003-151517 A JP 2007-157609 A JP 2009-266530 A

  However, the structure disclosed in Patent Document 2 requires other materials such as a conductive adhesive in order to maintain electrical connection. Moreover, in patent document 3, in order to prevent the penetration | invasion of a sealing agent, it is necessary to apply | coat a sealing agent to another specific location, and it was desired to be solved with a simpler structure.

  The present invention solves the above-described conventional problems, and uses a sealing plate that does not increase contact resistance between sealing plate members while storing a battery at a high temperature for a long period of time. An object of the present invention is to provide a battery having a stable internal resistance.

  In order to solve the above-described conventional problems, the present invention stores a power generation element in which a positive electrode material and a negative electrode material are arranged to face each other with a separator in a battery case together with an electrolyte, and an opening of the battery case is formed between a cap and a PTC element. And a sealing plate formed by laminating a filter to which a spacer and a metal valve body are attached, and a battery sealed by a gasket coated with a sealing material, and a convex portion is provided on the surface of the cap facing the PTC element. The PTC element is sandwiched between the outer peripheral folded portion of the filter to which the spacer and the metal valve body are attached, and the convex portion.

  With the above configuration, when the electrical connection of the sealing plate member in the sealing plate is ensured, and when the fluidity of the sealing agent is increased while storing the battery at a high temperature for a long time or due to a rapid temperature change, Since the sealing agent cap and the PTC element can be prevented from entering the electrically conductive contact, a sealing plate having a stable resistance can be provided. In other words, even in environments where the viscosity of the sealant decreases and the fluidity of the sealant increases, such as in high-temperature environments, the internal resistance can be stabilized by configuring a sealing plate structure that ensures electrical connection between the sealing plate members. Battery can be provided.

Sectional drawing of the battery in one embodiment of this invention The expanded sectional view of the sealing board in one embodiment of the present invention (A) The top view of the principal part of the sealing board in one embodiment of this invention, (b) The side view of the sealing board in one embodiment of this invention (A) The top view of the principal part of the sealing board in one embodiment of this invention, (b) The side view of the sealing board in one embodiment of this invention The expanded sectional view of the sealing board in one embodiment of the present invention

  According to a first aspect of the present invention, a power generating element in which a positive electrode material and a negative electrode material are arranged to face each other via a separator is housed in a battery case together with an electrolyte, and an opening of the battery case is formed with a cap, a PTC element, a spacer, In a battery formed by sealing with a sealing plate formed by laminating filters attached with metal valve bodies and a gasket coated with a sealing material, a convex portion is provided on a surface facing the PTC element of the cap, and the spacer The battery is characterized in that the PTC element is sandwiched between the outer peripheral folded portion of the filter to which the metal valve body is attached and the convex portion.

  With this configuration, when the fluidity of the sealant increases, the battery has a stable internal resistance that prevents the sealant from entering the electrically conductive contact between the sealing plate members and does not increase the contact resistance. can do.

A second invention according to the present invention is a battery according to the first invention, wherein the protrusion is ring-shaped. By adopting this configuration, it is possible to prevent the sealing agent having increased fluidity from entering the electrically conductive contact between the sealing plate members, and to more reliably prevent an increase in internal resistance between the sealing plate members. .

  A third invention according to the present invention is the battery according to the first invention, wherein the convex portion is constituted by a plurality of protrusions. By configuring with a plurality of protrusions, the contact pressure of each protrusion to the PTC element increases, and a more stable electrical connection is possible.

  A fourth invention according to the present invention is the battery according to any one of the first to third inventions, wherein the tip of the convex portion is sharp. By making the tip of the convex portion sharp, the contact pressure with the PTC element can be further increased, and more reliable electrical connection can be realized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.

  FIG. 1 is a cross-sectional view of a cylindrical nonaqueous electrolyte battery according to an embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view of a sealing plate according to an embodiment of the present invention. This battery is a cylindrical lithium primary battery using lithium as a positive electrode material and a negative electrode material using manganese dioxide as an active material. A strip-shaped positive electrode plate 1 in which an active material mixture mainly containing manganese dioxide is filled in a current collecting metal core, a strip-shaped negative electrode plate 2 made of lithium metal, and a separator 3 interposed between the positive and negative electrodes are spirally formed. The wound power generation element is housed in the battery case 4 together with the organic electrolyte. A sealing plate 6 is attached to the upper opening of the battery case 4 with a gasket 5 interposed therebetween. A positive electrode lead 7 connected to a positive electrode core member is connected to the sealing plate 6. A negative electrode lead 8 connected to the negative electrode plate 2 is connected to the battery case 4.

  As shown in FIG. 2, the sealing plate 6 is configured by sequentially laminating a cap 9 as a sealing plate member, a PTC element 10, a filter 11 with a spacer 11 and an aluminum valve 12 attached thereto, and is incorporated in the outer peripheral portion of the sealing plate 6. The gasket 5 and the sealant 14 applied to the surface where the gasket 5 and the sealing plate 6 are in contact with each other.

  The cap 9 is a positive electrode terminal of the battery. Since the cap 9 is affected by the external environment such as high temperature and high humidity, a material which is not easily rusted is preferable. Further, since the cap 9 is used as a positive electrode terminal of the battery, it is necessary to use a highly conductive material for the surface of the cap 9. The cap 9 has a gas vent hole. Moreover, the convex part 15 is provided in the surface facing the PTC element 10 at the time of the lamination | stacking. The shape of the convex portion 15 is not particularly limited as long as it can secure electrical contact with the PTC, and the height is preferably a height that does not penetrate the PTC 10. The cap 9 is produced, for example, by performing press molding of several steps on a material obtained by plating nickel (Ni) on stainless steel (SUS430) having a thickness of about 0.3 mm.

  The PTC element 10 is an element whose resistance value increases as the temperature rises. The function of the PTC element 10 is to suppress the overcurrent by increasing the resistance of the PTC element 10 when the temperature of the battery rapidly increases due to the overcurrent.

  The spacer 11 determines the operating pressure of the aluminum valve body 12 in order to release the gas generated inside the battery. The spacer 11 has a donut shape and controls the operating pressure of the aluminum valve body 12 according to the size of the inner diameter. The spacer 11 is produced, for example, by punching stainless steel (SUS430) having a thickness of 0.2 mm into a donut shape.

The aluminum valve body 12 is a valve body that deforms as the internal pressure of the battery increases. The aluminum valve body 12 is deformed as the internal pressure of the battery increases due to abnormal heat generation of the battery. This prevents the battery from bursting. The aluminum valve body 12 is produced by, for example, heat laminating 0.05 mm thick adhesive polyethylene on the surface on which the filter 13 is attached to aluminum having a thickness of 0.025 mm and non-adhesive polyethylene having a thickness of 0.05 mm on the surface opposite to the adhesive polyethylene.

  The filter 13 fixes the spacer 11 and the aluminum valve body 12. Further, it is welded to the positive electrode lead 7 of the power generating element. For example, the filter 13 is formed by punching a stainless steel 444 having a thickness of 0.3 mm in a circular shape, providing a through hole in the center, forming a step by performing press molding in several steps, attaching an aluminum valve body 12 to the formed surface, and attaching the spacer 11 The spacer 11 and the aluminum valve body 12 are fixed by caulking the periphery of the filter 13 to form the outer peripheral folded portion 16.

  The gasket 5 prevents leakage of the organic electrolyte from between the sealing plate 6 and the battery case 4. The gasket 5 is produced, for example, by injection molding polypropylene.

  The sealing agent 14 fills the gap between the sealing plate 6 and the gasket 5 when the battery is sealed to prevent leakage of the organic electrolyte. It is also applied to the surface where the battery case 4 and the gasket 5 are in contact with each other to prevent leakage of the organic electrolyte as described above. The main component of the sealant 14 is preferably a material having an affinity for the material of the gasket 5. The sealing agent 14 is prepared by mixing, for example, bron asphalt and toluene at a ratio of 1: 2.

  As shown in FIG. 2, the cap 9 as the sealing plate 6 has a convex portion 15 that comes into contact with the PTC element 10 so as to increase the contact pressure by being laminated on the surface facing the PTC element 10, Electrical continuity between the cap 9 and the PTC element 10 is ensured.

  With this configuration, when the battery is stored at a high temperature for a long period of time or the fluidity of the sealant 14 increases in an environment with a rapid temperature change, the convex portion 15 provided on the cap 9 has the PTC. By increasing the contact pressure with the element 10, it is possible to prevent the sealant from entering the conductive contact between the convex portion 15 and the PTC 10, and to keep the electrical contact of the PTC element 10 well. Moreover, since the electrical contact between the PTC element 10 and the filter 13 is also maintained well by the outer periphery folding portion 16 of the filter, an increase in battery internal resistance can be suppressed.

  The convex part 15 provided in the said cap 9 will not be specifically limited if it is a shape which can hold | maintain the connection with the PTC element 10. FIG. As shown in FIG. 3, by providing a ring shape on the surface facing the PTC element 10, the sealant with increased fluidity is prevented from entering between the sealing plate members, and the internal resistance between the sealing plate members is increased. Can be prevented more reliably.

Moreover, about the convex part 15 which raises the contact pressure with the PTC element 10 of the cap 9, the form comprised by several protrusion as shown in FIG. 4 may be sufficient. By comprising a plurality of protrusions, the contact pressure of each protrusion to the PTC element is increased, and a more stable electrical connection is possible. As shown in FIG. It may be sharp. A more reliable electrical connection can be realized by increasing the contact pressure with the PTC element by sharpening the tip of the convex portion.

  Examples of the battery using the sealing plate having the above structure and comparative examples are shown. Here, a test for confirming whether or not the sealing agent softened in an environment accompanied with a rapid temperature change to check whether or not the sealing plate member entered the electrically conductive contact was performed.

  First, a cap 13 as a sealing plate member, a PTC element 10, a spacer 11 and an aluminum valve body 12 are sandwiched and a filter 13 constituted by caulking the outer peripheral portion is sequentially laminated, and the sealing is performed by a gasket incorporated in the outer peripheral portion of the sealing plate 6. A plate 6 was constructed and used as a sealing plate A of a comparative example.

  Next, as shown in FIG. 3, the cap 9 is provided with a ring-shaped convex portion 15 having conductivity, and a sealing plate 6 having a structure in which the PTC element 10 is sandwiched between the outer peripheral folded portion 16 of the filter is manufactured. Was a sealing plate B.

  Also, as shown in FIG. 4, a structure in which the cap 9 formed of the plurality of projections 15 is laminated so as to face the PTC element 10 and the PTC element is sandwiched between the outer peripheral folded portion 16 of the filter. This was designated as a sealing plate C.

  Further, as shown in FIG. 5, a sealing plate 6 constituted by laminating a sharp tip of the convex portion 15 provided on the cap 9 so as to face the PTC element 10 was produced, and this was used as a sealing plate D. The height of the convex portion 15 of the sealing plates B to D was 0.1 mm.

  Using the sealing plates A to D, the open end of the battery case 4 was bent inward to seal, and 50 2 / 3A size cylindrical batteries were produced. Table 1 shows the measurement results of the internal resistance of the battery after 100 cycles of the heat shock test in which the above battery has one cycle of 85 ° C. for 30 minutes and −40 ° C. for 30 minutes.

  From the above results, in the sealing plates B to D provided with the convex portions 15, even when the fluidity of the sealing agent 14 is increased, the sealing agent 14 is prevented from entering the conductive contact between the cap 9 and the PTC element 10. It was confirmed that the effect of preventing an increase in internal resistance was exhibited.

  ADVANTAGE OF THE INVENTION According to this invention, the battery which can suppress a raise of internal resistance can be obtained even when it preserve | saves at high temperature for a long period of time, or in the environment accompanied by a rapid temperature change.

DESCRIPTION OF SYMBOLS 1 Positive electrode plate 2 Negative electrode plate 3 Separator 4 Battery case 5 Gasket 6 Sealing plate 7 Positive electrode lead 8 Negative electrode lead 9 Cap 10 PTC element 11 Spacer 12 Aluminum valve body 13 Filter 14 Sealant 15 Convex part 16 Outer turning part

Claims (4)

A power generation element in which a positive electrode material and a negative electrode material are disposed opposite to each other with a separator interposed between them is housed in a battery case together with an electrolyte, and a filter having a cap, a PTC element, a spacer, and a metal valve element attached to the opening of the battery case. In a battery formed by sealing with a laminated sealing plate and a gasket coated with a sealing material, a convex portion is provided on the surface of the cap facing the PTC element, and a filter having a spacer and a metal valve attached thereto is provided. A battery having a structure in which the PTC element is sandwiched between an outer periphery folded portion and the convex portion. The battery according to claim 1, wherein the convex portion of the cap has a ring shape. The battery according to claim 1, wherein the convex portion of the cap is composed of a plurality of protrusions. The battery according to any one of claims 1 to 3, wherein a tip of the convex portion of the cap is sharp.