JP5023634B2 - Positive electrode conductor and flat type nonaqueous electrolyte battery - Google Patents

Description

  The present invention relates to a positive electrode conductor disposed between a positive electrode mixture and a positive electrode can to improve electrical contact, and a flat type non-aqueous electrolyte battery including the positive electrode conductor.

  In recent years, there has been an increasing demand for use of the above-described flat type non-aqueous electrolyte battery, for example, a lithium coin battery, at a high temperature, and driving at 100 ° C. or higher is required. In a normal lithium coin battery, when placed in a high temperature environment, the manganese dioxide of the positive electrode reacts with the electrolyte to generate gas, resulting in an increase in the internal pressure of the battery and swelling of the battery. There is a concern that contact between the mixture and the positive electrode can may be lost, resulting in poor discharge.

Conventionally, as a flat type non-aqueous electrolyte battery that has taken measures to eliminate such a poor contact between the positive electrode mixture and the positive electrode can, for example, in the positive electrode ring disposed between the positive electrode mixture and the positive electrode can, Some of the flat non-aqueous electrolyte batteries have a folded portion that protrudes in the direction of the positive electrode can. For example, in this flat type non-aqueous electrolyte battery, even if the internal pressure rises and the battery swells, the folded portion of the positive electrode ring The contact state between the positive electrode mixture and the positive electrode can can be maintained by the amount protruding in the positive electrode can direction.
JP-A-10-27617

  However, the above-described conventional flat type nonaqueous electrolyte battery can maintain the contact state between the positive electrode mixture and the positive electrode can when placed in a high temperature environment, but this flat type nonaqueous electrolyte battery is manufactured. In other words, when the flat type nonaqueous electrolyte battery is not expanded, an extra space is required between the positive electrode mixture and the positive electrode can for the folded portion of the positive electrode ring. There was a problem of inviting a decline.

  The present invention has been made paying attention to the above-described conventional problems, and it is possible to maintain a good contact state between the positive electrode mixture and the positive electrode can when stored in a high temperature environment. In addition, an object of the present invention is to provide a positive electrode conductor and a flat type non-aqueous electrolyte battery that can prevent a decrease in battery capacity.

As a result of intensive studies to achieve the above object, the present inventor has placed a gap in the conductive plate portion of the positive electrode conductor disposed between the positive electrode mixture and the positive electrode can in the inner peripheral edge portion of the conductive plate portion . A leaf spring-like protrusion that can be positioned in the same plane as the conductive plate portion in a state in which a force in the direction opposite to the positive electrode can is applied while projecting toward the positive electrode can . It is formed on the outer periphery only set and a wall portion for mating with the positive electrode mixture, by a ring-shaped, found that the above object can be attained, thereby completing the present invention.

That is, the positive Gokushirube collector of the present invention is a positive electrode conductive member provided with the conductive plate portion arranged between the positive electrode mixture and the positive electrode can, the conductive plate portion is, the inner peripheral edge portion of the conductor Denban portion spaced apart, the leaf spring-like protrusions may be located in the conductor Denban portion in the same plane while applying a opposing force to the projecting and the positive electrode canister toward the cathode can direction, the is formed on the outer peripheral edge portion of the conductive plate portion have a wall portion that mates with the positive electrode mixture, which is characterized in that a structure is ring-shaped, the above-described conventional configuration of the positive electrode conductive material It is a means to solve the problem.

On the other hand, the flat type non-aqueous electrolyte battery of the present invention includes a negative electrode mixture, a negative electrode cup containing the negative electrode mixture, a positive electrode mixture, a positive electrode can containing the positive electrode mixture, the negative electrode mixture, A separator disposed between the positive electrode mixture, and a positive electrode conductor provided with a conductive plate portion disposed between the positive electrode mixture and the positive electrode can, the conductive plate portion of the positive electrode conductor, The conductive plate portion is provided at an interval on the inner peripheral edge , protrudes toward the positive electrode can , and is positioned in the same plane as the conductive plate portion with a force in a direction opposite to the positive electrode can. a leaf spring-like projections to obtain, is formed on the outer peripheral edge portion of the electrically Denban part have a wall portion that mates with the positive electrode mixture, which is characterized in that a structure is ring-shaped, the flat type The configuration of the nonaqueous electrolyte battery is used as a means for solving the above-described conventional problems.

  In the flat type nonaqueous electrolyte battery of the present invention, when stored in a high temperature environment, even when the internal pressure rises and the battery swells, the leaf spring that protrudes toward the positive electrode can of the conductive plate portion of the positive electrode conductor Since the protrusions follow the deformation of the positive electrode can, the contact state between the positive electrode mixture and the positive electrode can is maintained through the positive electrode conductor.

  Further, the leaf spring-like protrusions of the conductive plate portion of the positive electrode conductor are flush with the conductive plate portion in a state where a force in the direction opposite to that of the positive electrode can is applied, that is, in the state where a flat type nonaqueous electrolyte battery is manufactured. Therefore, the extra space that has been required in the past is unnecessary, and as a result, a decrease in battery capacity is avoided.

  According to the present invention, since it is configured as described above, it is needless to say that a good contact state between the positive electrode mixture and the positive electrode can can be maintained when stored in a high temperature environment. It has a very good effect that it can be prevented.

  As for the positive electrode conductor of the present invention, it is preferable to use a material that does not dissolve when used in a lithium coin battery, in addition to being able to ensure energization, such as stainless steel (SUS). SUS430, which is generally used as a material for the can, can be used, and it is even more preferable to use a material that has a strong spring property.

  Further, in the positive electrode conductor of the present invention, for example, when employed in a lithium coin battery, in order to secure the internal volume as much as possible, it is desirable to form the conductive plate portion in a ring shape, but the present invention is not limited to this. In addition, the conductive plate portion can be C-shaped, and the conductive plate portion can be disk-shaped.

  At this time, if the thickness of the conductive plate portion is less than 0.05 mm, the strength is reduced. On the other hand, if the thickness of the conductive plate portion exceeds 0.50 mm, the internal volume of the lithium coin battery decreases. The thickness of the conductive plate portion is preferably 0.05 to 0.50 mm.

  Furthermore, in the positive electrode conductor of the present invention, if the protruding amount in the thickness direction of the conductive plate portion of the leaf spring-like protrusion is less than 0.05 mm, the effect of suppressing the increase in internal resistance is low, while the leaf spring-like protrusion If the protruding amount in the thickness direction of the conductive plate portion exceeds 10.00 mm, it may affect the internal volume of the lithium coin battery. Therefore, the protruding amount in the thickness direction of the conductive plate portion of the leaf spring-like protrusion is The thickness is desirably 0.05 to 10.00 mm, and more desirably 0.10 to 3.00 mm.

  Furthermore, in the positive electrode conductor of the present invention, if the angle of the leaf spring-shaped protrusion with respect to the conductive plate portion exceeds 45 °, the possibility of deformation due to a large load applied to the bending of the spring increases. As shown, the angle θ of the leaf spring-like protrusion 13 with respect to the conductive plate portion 11 is preferably within 45 °, more preferably about 30 °.

  Furthermore, as shown to Fig.5 (a), the number of the leaf | plate spring-like protrusions 13 provided in the electroconductive board part 11 of the positive electrode conductor 10 of this invention should just be one, and quantity is not specifically limited. As shown in FIG. 5B, two leaf spring-like projections 13 are provided so as to face each other, and as shown in FIG. 5C, the three leaf spring-like projections 13 are spaced at an interval of 120 °. Alternatively, as shown in FIG. 5D, four leaf spring-like projections 13 can be provided at intervals of 90 °.

  Furthermore, in the positive electrode conductor of the present invention, the ratio between the width and the length of the leaf spring-like projections provided on the conductive plate portion is not particularly specified, but the ratio is appropriately set, for example, as in the embodiments shown below, The width and length of the protrusion can be formed at a ratio of 1: 1. Further, the ratio between the thickness and the length of the leaf spring-like protrusion is not particularly specified, but it is difficult to obtain the spring property when the ratio between the thickness and the length is 1: 1. For example, as in the embodiment shown below, the thickness and length of the leaf spring-like protrusions can be formed at a ratio of 1:30.

  On the other hand, in the flat type non-aqueous electrolyte battery of the present invention, the contact step with the positive electrode conductor of the positive electrode can is provided with a storage step for housing the contact portion with the positive electrode conductor of the positive electrode conductor and the positive electrode mixture. By adopting this configuration, the contact portion between the positive electrode conductor and the positive electrode conductor of the positive electrode mixture is accommodated in the storage step of the positive electrode can, so that an extra space can be eliminated. The capacity will be increased.

  In the flat type non-aqueous electrolyte battery of the present invention, a material generally used for a lithium coin battery can be used. For example, as a solvent of an electrolytic solution, PC (propylene carbonate), EC (ethylene・ Carbonates such as carbonates, esters such as GBL (γ-butyrolactone), ethers such as DME (dimethyl carbonate) and DEC (diethyl carbonate), NMP (N-methyl pyrrolidone), etc. Amides and sulfoxides such as DMSO (dimethyl sulfoxide) can be employed.

  Moreover, PP (polypropylene), PPS (polyphenylene sulfide), PFA (perfluoroalkoxyalkane), etc. can be adopted as the gasket material for joining the negative electrode cup and the positive electrode can. PP, PPS, PBT (polybutylene terephthalate), glass, or the like can be used as a separator interposed between the two.

  Furthermore, PTFE (polytetrafluoroethylene) or the like can be used as the positive electrode binder, and graphite or carbon can be used as the positive electrode conductive material. It is not something.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example.

Example 1
FIG. 1 shows a positive electrode conductor according to an embodiment of the present invention, and FIGS. 2 and 3 show lithium coins as a flat type nonaqueous electrolyte battery according to an embodiment of the present invention assembled with the positive electrode conductor. Battery is shown.

  As shown in FIG. 2, this lithium coin battery 1 includes a negative electrode cup 2 made of stainless steel, a positive electrode can 3 made of stainless steel, and a negative electrode mixture made of a lithium-aluminum alloy formed into a disk shape of φ19 mm. 4 and a positive electrode mixture 5 molded in a pellet form, an annular peripheral edge 2a of the negative electrode cup 2 containing the negative electrode mixture 4, and an annular peripheral edge 3a of the positive electrode can 3 containing the positive electrode mixture 5. Are fitted together via a sealing gasket 7 made of polyphenylene sulfide (PPS).

In this embodiment, the diameter φ is 24.5 mm, the thickness is 4.9 mm, and the gap between the negative electrode mixture 4 and the positive electrode mixture 5 facing each other in the sealed interior between the negative electrode cup 2 and the positive electrode can 3. The separator 6 made of polyphenylene sulfide having a basis weight of 70 g / m ² and a thickness of 300 μm is interposed.

  The positive electrode mixture 5 is prepared by mixing a conductive material mainly composed of baked manganese dioxide and graphite, a binder mainly composed of polytetrafluoroethylene (PTFE), and water, and subjecting the mixed solution to a heat treatment to remove water. It is made by evaporating to dryness. Further, in the electrolytic solution, lithium perchlorate (0.5 mol / l) is used as a solute, and propylene carbonate and dimethoxyethane (volume ratio 1: 1) are used as a solvent.

  In this case, inside the negative electrode cup 2 and the positive electrode can 3, as shown in FIG. 1, a ring-shaped conductive plate portion 11 disposed between the positive electrode mixture 5 and the positive electrode can 3, and this conductive A positive electrode conductor 10 made of stainless steel having a thickness of 0.1 mm and provided with an annular wall portion 12 continuously formed on the outer peripheral edge portion of the plate portion 11 and fitted to the positive electrode mixture 5 is provided. As shown in FIG. 3, the conductive plate portion 11 of the positive electrode conductor 10 is the same as the conductive plate portion 11 in a state of protruding toward the positive electrode can 3 and applying a force in the direction opposite to the positive electrode can 3. Four leaf spring-like projections 13 which can be located in the plane are provided at an interval of 90 °.

  In this embodiment, the angle θ of the plate spring-like protrusion 13 with respect to the conductive plate portion 11 is set to about 1 ° so that the protrusion amount of the plate-like protrusion 13 in the thickness direction of the conductive plate portion 11 is 0.05 mm. The width B and the length A of the spring-like protrusion 13 are both 3 mm, the ratio is 1: 1, and the ratio of the thickness C and the length A of the leaf spring-like protrusion 13 is 1:30.

  In this lithium coin battery 1, a housing step 3 b is provided at the contact portion of the positive electrode can 3 with the positive electrode conductor 10, and the contact portion of the positive electrode conductor 10 and the positive electrode mixture 5 with the positive electrode conductor 10 can be accommodated. It is like that.

  In the lithium coin battery 1, when stored in a high temperature environment, as shown in FIG. 3, even if the internal pressure rises and the battery swells, the direction of the positive electrode can 3 of the conductive plate portion 11 of the positive electrode conductor 10 is increased. Since the leaf spring-like protrusion 13 projecting toward the deformation follows the deformation of the positive electrode can 3, the contact state between the positive electrode mixture 5 and the positive electrode can 3 is maintained via the positive electrode conductor 10.

  Further, the leaf spring-like protrusion 13 of the conductive plate portion 11 of the positive electrode conductor 10 is shown in FIG. 2 in a state where a force in the direction opposite to that of the positive electrode can 3 is applied, that is, in a state where the lithium coin battery 1 is manufactured. As described above, since the conductive plate portion 11 can be positioned in the same plane and can be flat, an unnecessary space that has been conventionally required becomes unnecessary, and as a result, a decrease in battery capacity is avoided.

  Further, in this lithium coin battery 1, since the accommodation step 3 b is provided at the contact portion of the positive electrode can 3 with the positive electrode conductor 10, the contact portion of the positive electrode conductor 10 and the positive electrode mixture 5 with the positive electrode conductor 10 is provided. When the positive electrode can 3 is housed in the accommodation step 3b, an extra space can be eliminated, and as a result, the capacity can be further increased.

(Example 2)
As Example 2, the angle θ of the leaf spring-like projection 13 with respect to the conductive plate portion 11 is set to about 2 ° so that the protruding amount of the leaf spring-like projection 13 in the thickness direction of the conductive plate portion 11 is 0.10 mm. Produced a lithium coin battery 1 with the same specifications as in Example 1.

(Example 3)
In Example 3, the angle θ of the leaf spring-like projection 13 with respect to the conductive plate portion 11 is set to about 5 ° so that the protruding amount of the leaf spring-like projection 13 in the thickness direction of the conductive plate portion 11 is 0.25 mm. Produced a lithium coin battery 1 with the same specifications as in Example 1.

Example 4
In Example 4, the angle θ of the leaf spring-like projection 13 with respect to the conductive plate portion 11 is set to about 15 ° so that the protruding amount of the leaf spring-like projection 13 in the thickness direction of the conductive plate portion 11 is 0.80 mm. Produced a lithium coin battery 1 with the same specifications as in Example 1.

(Example 5)
As Example 5, the angle θ of the leaf spring-like projection 13 with respect to the conductive plate portion 11 is set to about 20 ° so that the protruding amount of the leaf spring-like projection 13 in the thickness direction of the conductive plate portion 11 is 1.00 mm. Produced a lithium coin battery 1 with the same specifications as in Example 1.

(Example 6)
As Example 6, the angle θ of the leaf spring-like protrusion 13 with respect to the conductive plate portion 11 was set to about 45 ° so that the protruding amount of the leaf spring-like projection 13 in the thickness direction of the conductive plate portion 11 was 2.00 mm. Produced a lithium coin battery 1 with the same specifications as in Example 1.

(Example 7)
As Example 7, in order to set the protrusion amount of the plate-like protrusion 13 in the thickness direction of the conductive plate portion 11 to 3.00 mm, the angle θ of the plate-spring-like projection 13 with respect to the conductive plate portion 11 is about 30 °. Lithium coin battery in which the width B of the spring-like protrusion 13 is 3 mm, the length A is 6 mm, the ratio is 1: 2, and the ratio of the thickness C to the length A of the leaf spring-like protrusion 13 is 1:60. 1 was produced.

(Comparative Example 1)
As Comparative Example 1, a lithium coin battery was manufactured with the same specifications as Example 1 except that the positive electrode conductor 10 in which the plate spring-like protrusions 13 were not installed on the conductive plate portion 11 was provided.

(Comparative Example 2)
As Comparative Example 2, a lithium coin battery was produced with the same specifications as in Example 1 except that the protruding amount in the thickness direction of the conductive plate portion 11 of the leaf spring-like protrusion 13 was 0.01 mm.

(Comparative Example 3)
As Comparative Example 3, the angle θ of the leaf spring-like projection 13 with respect to the conductive plate portion 11 is set to about 50 ° so that the protruding amount of the leaf spring-like projection 13 in the thickness direction of the conductive plate portion 11 is 4.50 mm. Lithium coin battery in which the width B of the spring-like protrusion 13 is 3 mm, the length A is 6 mm, the ratio is 1: 2, and the ratio of the thickness C to the length A of the leaf spring-like protrusion 13 is 1:60. 1 was produced.

  Therefore, when the internal resistance values before and after storing the lithium coin batteries 1 of Examples 1 to 7 and the lithium coin batteries of Comparative Examples 1 to 100 in a high temperature environment of 120 ° C. for 100 hours were measured, the results shown in Table 1 were obtained. Obtained.

  From the measurement results shown in Table 1, in the lithium coin battery of Comparative Example 1, when the battery swells during high temperature storage, the positive electrode can 3 is separated from the positive electrode mixture 5, and the internal resistance value is increased. I understand. Further, in the lithium coin battery of Comparative Example 2 in which the protruding amount in the thickness direction of the conductive plate portion 11 of the leaf spring-like protrusion 13 is extremely small, the leaf spring-like protrusion 13 is formed in the positive electrode can 3 when the battery swells during high temperature storage. It can be seen that the internal resistance value is increased similarly to the lithium coin battery of Comparative Example 1.

  On the other hand, in the lithium coin battery 1 of Example 1, when the battery swells during high-temperature storage, the leaf spring-like protrusion 13 follows the deformation of the positive electrode can 3, so that the positive electrode conductor 10 is interposed. Since the contact state between the positive electrode mixture 5 and the positive electrode can 3 is maintained, it can be seen that the increase in the internal resistance value is suppressed. In the lithium coin battery 1 of the first embodiment, the leaf spring-like protrusion 13 Since the protruding amount of the conductive plate portion 11 in the thickness direction is small, the suppressing effect is slightly small.

  Then, by changing the angle θ of the plate spring-like protrusion 13 with respect to the conductive plate portion 11 within a range of 45 °, the protrusion amount of the plate-like spring 13 in the thickness direction of the conductive plate portion 11 is more preferably within the range (0. In the lithium coin batteries 1 of Examples 2 to 6 that have been changed to a value of 10 to 3.00 mm), the leaf spring-like protrusion 13 reliably follows the deformation of the positive electrode can 3 when the battery swells during high temperature storage. Thus, since the contact state between the positive electrode mixture 5 and the positive electrode can 3 through the positive electrode conductor 10 is well maintained, it can be seen that the increase in the internal resistance value is suppressed to a very small value.

  Further, by setting the angle θ of the leaf spring-like projection 13 to the conductive plate portion 11 to about 30 ° and the length A of the leaf spring-like projection 13 to 6 mm, the thickness direction of the conductive plate portion 11 of the leaf spring-like projection 13 is set. Even in the lithium coin battery 1 of Example 7 in which the protrusion amount of the battery is changed to 3.00 mm which is the upper limit of the more preferable range, the leaf spring-like protrusion 13 is deformed in the positive electrode can 3 when the battery swells during high temperature storage. By reliably following, the contact state between the positive electrode mixture 5 and the positive electrode can 3 through the positive electrode conductor 10 is well maintained, so that the increase in the internal resistance value is suppressed to a very small degree. I understand that.

  The angle θ of the leaf spring-like projection 13 with respect to the conductive plate portion 11 is set to about 50 °, and the length A of the leaf spring-like projection 13 is set to 6 mm. In the lithium coin battery 1 of Comparative Example 3 in which the amount of protrusion of this is changed to 4.50 mm exceeding the more preferable range, the increase in the internal resistance value can be suppressed, but the leaf spring-like protrusion 13 with respect to the conductive plate portion 11 can be suppressed. Since the angle θ is increased and the length A of the leaf spring-like protrusion 13 is increased, the spring is likely to be deformed by applying a large load, and therefore cannot be employed.

  Therefore, in the lithium coin batteries 1 of Examples 1 to 7, when the battery capacity is prevented from being lowered and stored in a high-temperature environment, a good contact state between the positive electrode mixture 5 and the positive electrode can 3 is maintained. I was able to prove it.

It is plane explanatory drawing (a) and cross-sectional explanatory drawing (b) which show one Example of the positive electrode conductor of this invention. Example 1 FIG. 2 is a partial cross-sectional explanatory view showing a state before storage of a lithium coin battery incorporating the positive electrode conductor of FIG. 1. Example 1 It is a fragmentary sectional view showing the state after storage of a lithium coin battery incorporating the positive electrode conductor of FIG. Example 1 It is a cross-sectional explanatory drawing of the positive electrode conductor which made the bending angle of the leaf | plate spring-like protrusion by other Example of this invention large. It is plane explanatory drawing (a)-(d) of the positive electrode conductor in which the quantity and dimension of the leaf | plate spring-like protrusion by another Example of this invention differed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lithium coin battery (flat type nonaqueous electrolyte battery), 2 ... Negative electrode cup, 3 ... Positive electrode can, 3b ... Storage step, 4 ... Negative electrode mixture, 5 ... Positive electrode mixture, 6 Separator, 10 ... Positive electrode conductor, 11 ... conductive plate part, 13 ... leaf spring projection

Claims (5)

A positive electrode conductor comprising a conductive plate portion disposed between a positive electrode mixture and a positive electrode can,
The conductive plate portion is provided in the inner peripheral edge portion of the conductive plate portion with an interval, protrudes toward the positive electrode can and is applied with a force in a direction opposite to the positive electrode can. a leaf spring-like protrusions may be located in the same plane, are formed on the outer peripheral edge portion of the electrically Denban part have a wall portion that mates with the positive electrode mixture, a positive electrode, which is a ring-shaped conductor.   2. The positive electrode conductor according to claim 1, wherein an amount of protrusion in the thickness direction of the conductive plate portion of the leaf spring-like protrusion is 0.05 to 10.00 mm. Positive Gokushirube conductor according to claim 1 or 2, characterized in that the angle with respect to the guide Denban portion of the plate spring-like projection is within 45 °. A negative electrode mixture, a negative electrode cup containing the negative electrode mixture, a positive electrode mixture, a positive electrode can containing the positive electrode mixture, a separator disposed between the negative electrode mixture and the positive electrode mixture; In the flat type non-aqueous electrolyte battery provided with the positive electrode conductor provided with the conductive plate portion disposed between the positive electrode mixture and the positive electrode can,
Positive the conductive plate portion of the electrode conductive body, flat type nonaqueous electrolyte battery which is a conductive plate portion according to any one of claims 1 to 3.   5. The flatness according to claim 4, wherein a housing step for accommodating the contact portion of the positive electrode conductor and the positive electrode mixture with the positive electrode conductor is provided in a contact portion of the positive electrode can with the positive electrode conductor. Type non-aqueous electrolyte battery.

Images