JP2012248280A - Iron disulfide and lithium primary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an iron disulfide and lithium primary battery which has high capacity and an excellent high load discharge property at the same time.SOLUTION: An iron disulfide and lithium primary battery includes a positive electrode plate formed by filling and holding a positive electrode mixture obtained by dispersing iron disulfide, a carbon conductive material, and a binder in expanded metal within the range of porosity of 25 to 35%, and a negative electrode plate constituted by lithium alloyed by one kind of an element or more among Sn, Mg, Zn, Bi, and Al. The theoretical capacity of the positive electrode plate per unit area is 35 to 70 mAh/cm, and the total mass of elements alloyed with the negative electrode plate is desirably 0.1 to 3% to the total mass of the negative electrode plate.

Description

  The present invention relates to a non-aqueous electrolyte battery having a positive electrode containing iron disulfide as a main active material and a negative electrode containing lithium as a main active material and using an organic solvent as an electrolyte, that is, iron disulfide / lithium primary It relates to batteries.

  The iron disulfide / lithium primary battery is composed of positive and negative electrode materials having a very high theoretical capacity of about 894 mAh / g for the positive electrode active material iron disulfide and about 3863 mAh / g for the negative electrode active material. It is a battery that is extremely excellent in terms of other characteristics such as low capacity and long-term reliability because of its capacity and light weight.

  In addition, the iron disulfide / lithium primary battery has an initial open circuit voltage of 1.7 to 1.8 V and an average discharge voltage of around 1.5 V, and electrolyzes other 1.5 V class primary batteries such as aqueous solutions. The practical value is also high from the viewpoint of compatibility with manganese batteries, alkaline manganese batteries, silver oxide batteries, air batteries and the like used for the liquid.

  A cylindrical iron disulfide / lithium primary battery in practical use is an electrode group in which a strip-like positive electrode plate and a negative electrode plate are wound many times through a separator inside a hollow cylindrical battery case. It is stored in shape. As can be seen from the description of Examples in Patent Document 1, in general, a positive electrode plate of this battery is made of an aluminum mixture mixed slurry (paint) obtained by mixing iron disulfide and a carbon conductive material / binder in a solvent. It is produced by coating and rolling on both sides of a flat foil. The negative electrode plate is lithium or an aluminum alloyed lithium plate (foil), and the separator is a polyethylene microporous film. The current collection between the electrode group and the battery case or sealing plate is performed by welding the lead wire taken out from the positive / negative electrode plate to the battery case / sealing plate, or by connecting the positive / negative electrode plate to the battery case / sealing plate. It is secured in the form of a contact system between.

JP 2005-529467 A JP 2006-216352 A

  As mentioned above, iron disulfide / lithium primary batteries have high practical value, but the positive electrode active material, iron disulfide, expands in volume as it discharges, so the positive electrode active material is simply highly charged to increase battery capacity. Then, as the discharge progressed, the electrolyte solution in the positive electrode decreased, resulting in a phenomenon that the positive electrode active material could not be fully used.

  In view of the above problems, the iron disulfide / lithium primary battery of the present invention includes a positive electrode plate using iron disulfide as a positive electrode active material, a negative electrode plate using metal lithium as a negative electrode active material, and a separator, and the positive electrode The separator is sandwiched between a plate and the negative electrode plate, and these are wound. The positive electrode plate includes a positive electrode mixture in which iron disulfide, a carbon conductive material, and a binder are mixed, and an expanded metal. The positive electrode mixture is filled in the opening of the expanded metal, and the positive metal mixture is held in the expanded metal, and the porosity of the positive electrode plate is 25% or more and 35% or less, and the negative electrode plate Is a lithium alloyed with one or more elements selected from Sn, Mg, Zn, Bi and Al.

  According to the present invention, it is possible to provide an iron disulfide / lithium primary battery having high capacity and excellent high-load discharge characteristics.

It is explanatory drawing showing the frame | skeleton shape of the expanded metal of a rhombus. It is sectional drawing which shows an example of a structure of the iron disulfide and lithium primary battery which concerns on embodiment of this invention.

The inventors of the present application also investigated other types of battery technologies when studying iron disulfide / lithium primary batteries. For example, a 3V-class manganese dioxide / lithium primary battery using baked manganese dioxide or the like as a positive electrode active material is also widely used. When this battery is examined, the positive electrode is also formed inside the battery case. It has a configuration that houses a wound electrode group of a plate, a negative electrode plate, and a separator, but the positive electrode plate here is a mixture (granulated powder with low moisture content) consisting of manganese dioxide and a carbon conductive material / binder. The mainstream method is to fill and roll into expanded metal. (For example, see Patent Document 2 etc.)
The positive electrode plate of the expanded metal filling method as described above has an advantage that the productivity is higher than the method of applying slurry on both sides of the flat foil. In addition, filling the expanded metal makes it easy to make the positive electrode plate thicker and shorter, so reducing the excess separator (shortening), etc., increasing the active material in the battery and increasing the capacity of the battery It is thought that it is suitable for doing.

From the above-mentioned background, especially when aiming to increase the capacity of cylindrical iron disulfide / lithium primary batteries, the positive electrode plate is made thicker and shorter as the method of filling the iron disulfide positive electrode into expanded metal. It is considered advantageous to perform. However, when the positive electrode plate is simply made thicker and shorter, the area where the positive and negative electrode plates face each other is reduced, and the current density per unit area [mA / cm ² ] during discharge is excessive. Since the conditions are severe, there arises a problem that sufficient high-load discharge characteristics cannot be secured.

  In addition, since the iron disulfide of the positive electrode active material expands in volume with discharge, the positive electrode active material particles can be impregnated and penetrated into the positive electrode at the end of discharge and the positive electrode active material particles at the end of discharge can be prevented from falling off. The present inventors thought that it was necessary to consider how to fill the active material. However, since the known expanded metal filling type positive electrode plate handled manganese dioxide or the like having a relatively small volume expansion, it has not been studied how to cope with the volume expansion as described above. It was.

  The inventors of the present application have conducted various experiments based on the above-described examination, and as a result, have found that the porosity of the positive electrode plate is the key, and have come up with the present invention.

(Definition)
The positive electrode plate using iron disulfide as a positive electrode active material is a positive electrode plate in which the positive electrode active material is 90% or more of iron disulfide. Moreover, the negative electrode plate which uses metallic lithium as a negative electrode active material is a negative electrode plate whose negative electrode active material is 90% or more of metallic lithium. Expanded metal is a metal plate that is stretched by making a number of cuts and forming a large number of openings. The expanded metal mesh is a mesh.

  The porosity of the positive electrode plate is the ratio of the void volume in the positive electrode to the total positive electrode plate (including the expanded metal) volume (%) with respect to the positive electrode plate in the initial state in which only the preliminary discharge immediately after battery preparation was performed. ).

  The total mass of the negative electrode plate when the total mass of elements alloyed with lithium in the negative electrode plate does not include the mass of the negative electrode lead attached to the negative electrode plate. The mass mixing ratio of iron disulfide and carbon conductive material in the positive electrode mixture is from 97/3 to 93/7. From the mixing ratio of 3 parts by mass of carbon conductive material to 97 parts by mass of iron disulfide, iron disulfide is mixed. This means a mixing ratio range up to 93 parts by mass with respect to a mixing ratio of 7 parts by mass of the carbon conductive material, and includes both ends of the range.

The theoretical capacity of the positive electrode plate is calculated based on the mass [g] of the iron disulfide material held on the positive electrode plate, assuming that the material is theoretically the maximum four-electron reaction (894 mAh / g) [ mAh], and the theoretical capacity per unit area is obtained by dividing this value by the area [cm ² ] of the positive electrode plate.

(Overview)
The exemplary iron disulfide / lithium primary battery of the present invention employs an expanded metal filling method for the positive electrode plate, and the porosity is set in the range of 25% to 35% in consideration of the expansion of the iron disulfide material. . As a result, it is possible to ensure the electrolyte impregnation and permeability into the positive electrode at the end of battery discharge and to prevent the positive electrode active material particles from falling off at the end of discharge. As a result of intensive studies by the present inventors, when the porosity of the positive electrode plate is less than 25%, the electrolyte impregnation / penetration into the positive electrode at the end of discharge is reduced, and conversely, the porosity is greater than 35%. As a result, it became clear that the positive electrode active material particles at the end of the discharge became apparent from the positive electrode plate. In this respect, the porosity of the positive electrode is preferably in the range of 25% to 35%. As described above, the exemplary iron disulfide / lithium primary battery can suppress the voltage drop phenomenon at the end of the high-load discharge.

Further, lithium used for the negative electrode plate is alloyed with one or more elements of Sn, Mg, Zn, Bi, and Al. Thereby, the film | membrane formed in the negative electrode surface within a battery decreases, and the polarization by the side of the negative electrode at the time of discharge is reduced significantly. Specifically, when lithium is alloyed with one or more elements of Sn, Mg, Zn, Bi, and Al, the polarization on the negative electrode side during discharge is greatly reduced. At the same time, it also has the following effects. That is, in a system using iron disulfide for the positive electrode, impurities such as sulfate ions present in the iron disulfide material are eluted in the electrolyte solution, and there is a tendency to form a strong film having a large discharge inhibiting effect on the negative electrode lithium. is there. When lithium is alloyed with one or more elements of Sn, Mg, Zn, Bi, and Al, it is possible to suppress the formation of a strong film peculiar to the system using iron disulfide. The lithium alloyed with a different element as described above is, for example, a known manufacturing flow in which a metallic lithium ingot is melted and extruded to form a plate-like foil. It can be produced by a method such as adding. Even when such a negative electrode plate is combined with a positive electrode plate that has been made thicker and shorter by an expanded metal method, and the current density per unit area [mA / cm ² ] is discharged under severe conditions, the battery total The discharge voltage can be maintained at a high level.

  Therefore, according to the configuration as described above, it is possible to sufficiently ensure the high load discharge characteristics of the battery while taking advantage of the high capacity when the expanded metal type positive electrode is used.

In an exemplary iron disulfide / lithium primary battery, the theoretical capacity per unit area of the positive electrode plate can be set to 35 mAh / cm ² or more and 70 mAh / cm ² or less. If the theoretical capacity per unit area is less than 35 mAh / cm ^2, it is necessary to increase the positive electrode area (lengthening the positive electrode plate) in order to ensure battery capacity, and excess expanded metal or Since the separator is accommodated, it tends to be disadvantageous for high capacity and high output. On the other hand, if the theoretical capacity per unit area is larger than 70 mAh / cm ² , the positive electrode plate can be shortened and it is advantageous for high capacity, but the positive electrode thickness is excessive and the facing area between the positive and negative electrodes becomes insufficient. It is easy to ensure high load discharge characteristics.

  The total mass of elements to be alloyed with lithium in the negative electrode plate can be 0.1% or more and 3% or less with respect to the total mass of the negative electrode plate (the mass excluding leads for current collection). This is because if the total mass of the alloying elements is less than 0.1%, it is difficult to obtain the effect of reducing the coating on the negative electrode surface. Conversely, if the total mass of the alloying elements is greater than 3%, This is because the ratio of lithium as an active material is relatively low, which tends to be disadvantageous in increasing the capacity of the battery.

The carbon conductive material of the positive electrode can contain carbon powder having a BET specific surface area of 300 m ² / g or more. By including a carbon conductive material having a large specific surface area, it is possible to improve the impregnation property of the electrolytic solution into the positive electrode that is made thicker and shorter, and it is easy to ensure high load discharge characteristics.

  Moreover, the mass mixing ratio in the positive electrode mixture of iron disulfide and carbon conductive material can be set in the range of 97/3 to 93/7. If the mixing ratio of the carbon conductive material is less than the above range, it is difficult to ensure sufficient high rate discharge characteristics. When the mixing ratio of the carbon conductive material is larger than the above range, that is, when the mixing ratio of the iron disulfide as the active material is smaller than the above range, it is difficult to ensure the absolute capacity of the battery.

  The expanded metal of the positive electrode can be made of aluminum or stainless steel from the viewpoints of chemical stability to the electrolyte and low cost. In order to reduce the volume ratio of the expanded metal core material in the positive electrode plate as much as possible, the skeleton shape is preferably a rhombus (diamond shape).

  FIG. 1 shows a skeleton drawing of an expanded metal having a rhombus (diamond) mesh (mesh). The plate thickness T directly reflects the plate thickness of the metal plate before processing. A desirable plate thickness T that can impart appropriate flexibility to the positive electrode plate while suppressing breakage of the positive electrode plate during filling / compression and electrode group configuration is 0.1 mm or more and 0.15 mm or less. The step width W is a parameter that determines the thickness of the skeleton together with the plate thickness T. From the viewpoint of suppressing the breakage of the positive electrode plate as described above and reducing the volume ratio of the core material, W is 0.2 mm or more. A range of 0.3 mm or less is preferred. Further, the center-to-center distance LW in the long direction and the center-to-center distance SW in the short direction of the mesh are parameters that define the size of the hole formed in the expanded metal. Suitable for LW and SW from the viewpoint of sufficiently maintaining the current collection from the active material particles at a position away from the skeleton and ensuring the tensile strength as the core material while reducing the volume ratio of the core material as much as possible. The range is determined. As a result of the study by the present inventors from the above viewpoint, a preferable range of the center-to-center distance LW in the long direction is 2 mm or more and 3 mm or less, and a preferable range of the center-to-center distance SW in the short direction is 0.8 mm or more. It is 1.8 mm or less.

(Embodiment 1)
<Description of iron disulfide / lithium primary batteries>
FIG. 2 is a schematic cross-sectional view of an iron disulfide / lithium primary battery according to an embodiment of the present invention.

  This iron disulfide / lithium primary battery has a positive electrode plate 1 using iron disulfide as an active material and a negative electrode plate 2 using lithium as an active material. The electrode group is configured by winding the positive electrode plate 1, the negative electrode plate 2, and the separator 3 interposed therebetween in a spiral shape. This electrode group is housed in a bottomed cylindrical case 9 together with a non-aqueous electrolyte (not shown). A sealing plate 8 is attached to the opening of the case 9. A lead 4 connected to the core material of the positive electrode plate 1 is connected to the sealing plate 8. The lead 5 connected to the negative electrode plate 2 is coupled to the case 9. In addition, an upper insulating plate 6 and a lower insulating plate 7 are respectively provided at the upper and lower portions of the electrode group to prevent internal short circuits.

  The positive electrode plate 1 is produced as follows. After mixing iron disulfide and a conductive agent, a binder and water are added and kneaded to prepare a positive electrode mixture. Next, a predetermined amount of this positive electrode mixture is placed on the expanded metal, filled in the mesh, dried and compressed. Then, it cuts into a fixed size, peels a part of positive electrode mixture, welds the lead | read | reed 4 to the expanded metal of the part, and produces the strip | belt-shaped positive electrode plate 1. FIG.

  The strip-shaped negative electrode plate 2 is made of lithium (foil) alloyed with one or more elements of Sn, Mg, Zn, Bi, and Al. As the separator 3, a polyolefin microporous film or the like is used.

  The solvent used for the nonaqueous electrolytic solution is not particularly limited as long as it is an organic solvent used for a known nonaqueous electrolytic solution of a lithium primary battery. γ-Butyllactone, propylene carbonate, ethylene carbonate, 1,2-dimethoxyethane and the like can be used alone or in combination.

The supporting electrolyte constituting the non-aqueous electrolyte includes lithium perchlorate, lithium borofluoride, lithium hexafluorophosphate, lithium trifluoromethanesulfonate, lithium iodide, and LiN (CF that has an imide bond in the molecular structure. _{3 SO 2) 2, LiN (} C 2 F 5 SO 2) 2, LiN (CF 3 SO 2) (C 4 F 9 SO 2) , or the like can be used.

  Hereinafter, examples will be described in detail. The content of the present invention is not limited to these examples.

Example 1
<Production of battery>
95 parts by mass of iron disulfide having an average particle size (particle size at a volume fraction of 50%: D ₅₀ ) of 25 μm and Ketjen Black (EC300J manufactured by Lion Corporation, BET specific surface area: 800 m ² / g) After 5 parts by mass of the mixture is dry-mixed, an appropriate amount of water is added to and kneaded with PTFE disversion (Polyflon (registered trademark) D-1E manufactured by Daikin Industries, Ltd.), which is a binder. A positive electrode mixture was prepared. The solid content ratio of PTFE was adjusted to 5% by mass with respect to the total mass (total mass excluding moisture) of the positive electrode mixture after drying.

This positive electrode mixture was placed on an expanded metal, pushed into the mesh, filled, dried and compressed. During compression, the porosity of the positive electrode plate (the ratio of the void volume in the positive electrode to the positive electrode volume including the expanded metal) was adjusted to 30%. After that, it is cut to a fixed size (length 200 mm, width 44 mm, theoretical capacity per unit area of positive electrode: 50 mAh / cm ² ), a part of the positive electrode mixture is peeled off, and a lead is welded to the expanded metal of the part. I got a plate. Here, the expanded metal is made of aluminum and has a diamond-shaped mesh structure / skeleton shape as shown in FIG. The dimensions of the expanded metal are as follows: plate thickness T: 0.13 mm, step width W: 0.25 mm, center-to-center distance LW: 2.5 mm, center-to-center distance SW: 1.2 mm in the short direction. It was.

  The negative electrode plate 2 was a strip-shaped lithium alloy containing five types of alloying elements shown in Table 1 and a strip-shaped metallic lithium.

  Further, in the configuration of FIG. 1 (AA size), the separator 3 is a polyolefin microporous membrane (Celgard # 2400), and the electrolyte is 1,3-dioxolane (DOL) and 1,2-dimethoxyethane. Using a solution prepared by adding lithium iodide (LiI) to a mixed solvent of 2: 1 by volume (DME) to 1 mol / l, corresponding to each lithium alloy (or metallic lithium) Secondary-flow iron / lithium primary batteries a1 to a6 were produced. The battery a6 is a comparison target battery.

  Each battery is aged for 3 days in an atmosphere at 45 ° C. after assembly, and then corresponds to 5% of the positive electrode theoretical capacity (capacity calculated on the assumption that the discharge capacity of iron disulfide is 894 mAh / g). A preliminary discharge was performed. The following evaluation was performed after preliminary discharge.

<Battery evaluation>
The following (1) and (2) were evaluated for the battery produced above. Each test was carried out in the form of obtaining an average value with the number of batteries n = 5.

(1) 100 mA continuous discharge Each of the produced batteries was discharged at a constant current of 100 mA in a constant temperature atmosphere of 21 ° C., and the time until the closed circuit voltage reached 0.9 V was measured. This test corresponds to a low rate discharge test and is a test pattern for measuring the absolute electric capacity of a battery.

(2) DSC pulse discharge Each of the produced batteries was discharged at 1.5 W for 2 seconds in a constant temperature atmosphere at 21 ° C. and then discharged at 0.65 W for 28 seconds (pulse discharge) as one cycle. Pulse discharge was performed at a pace of 10 cycles per hour. While performing pulse discharge, the time until the closed circuit voltage reached 1.05 V was measured. This evaluation is a test pattern for high-load discharge that applies the method of the discharge test defined in ANSI C18.1M and assumes use in a digital still camera (DSC).

  The results are summarized in Table 2. All results are indexed with the performance value of the battery a6 as 100 (reference).

  This shows that the batteries a1 to a5 using Sn, Mg, Zn, Bi, and Al alloyed lithium for the negative electrode plate have excellent DSC pulse discharge characteristics. As a result of disassembling and analyzing these batteries, it was speculated that the batteries a1 to a5 had fewer films formed on the surface of the negative electrode plate than the battery a6, and the polarization on the negative electrode side during discharge was reduced.

  The battery produced as described above has a positive electrode plate length of 200 mm, which is only 70% of the positive electrode plate length of a general iron disulfide / lithium primary battery. Even when combined with a positive electrode plate that is thickened and shortened by such an expanded metal method, in the batteries a1 to a5, the polarization on the negative electrode side is greatly reduced, so that the discharge performance as a total battery is improved. It is inferred that it was kept high.

(Example 2)
In Example 2, in order to obtain knowledge about the porosity of the positive electrode plate, in the same positive electrode plate production as in Example 1, only the compression conditions were changed, and b1 to b1 having different porosity as shown in Table 3 were obtained. A positive electrode plate of b5 was prepared. Then, the battery constitution conditions thereafter were all the same as in the case of the battery a1 of Example 1 (using Sn alloyed lithium for the negative electrode), and batteries b1 to b5 having respective positive electrode void ratios were produced.

  Table 3 summarizes the results of performing aging / preliminary discharge on these batteries under the same conditions as described above, and then performing the performance evaluations (1) and (2) above. Here, each test was carried out in the form of obtaining an average value with the number of batteries n = 5. All the results are indexed with the performance value of the comparative battery a6 in Example 1 as 100 (reference).

  From Table 3, it can be seen that excellent DSC pulse discharge characteristics are difficult to obtain unless the porosity of the positive electrode plate is set in the range of 25 to 35%. Since the iron disulfide particles expand in volume along with the discharge, the battery b1 having a porosity of less than 25% lacks the porosity and decreases the electrolyte impregnation and permeability into the positive electrode at the end of discharge. It is considered that the DSC pulse discharge characteristics become low. In addition, in the battery b5 in which the porosity is larger than 35%, it is difficult to collect current between the expanded metal and the active material particles, and it is considered that both 100 mA continuous discharge and DSC pulse discharge remain in low characteristics.

(Example 3)
In Example 3, an experiment was conducted to obtain knowledge about the theoretical capacity per unit area of the positive electrode plate. Units as shown in Table 4 were obtained by changing the theoretical capacity per unit area by changing both the length and thickness of the positive electrode plate while keeping the mass and porosity of the positive electrode mixture the same as in Example 1. A positive electrode plate having a theoretical capacity per area was produced. On the other hand, the alloyed lithium containing Sn: 1.5% by mass was also used for the negative electrode plate, and the entire mass was the same as that of the battery a1 of Example 1, while corresponding to the length of the positive electrode plate. Thus, the length and thickness were adjusted. In addition, as to the following procedure, as in the case of Example 1, batteries c1 to c6 corresponding to the respective positive electrodes were produced.

  Table 4 summarizes the results of performing aging and preliminary discharge on these batteries under the same conditions as described above, and then performing the performance evaluations (1) and (2) above. Here, each test was carried out in the form of obtaining an average value with the number of batteries n = 5. All the results are indexed with the performance value of the comparative battery a6 in Example 1 as 100 (reference).

Table 4 shows that the theoretical capacity per unit area of the positive electrode plate is preferably 35 to 70 mAh / cm ² . In the battery c1 having a theoretical capacity per unit area of 30 mAh / cm ² , excess positive metal and separator are accommodated in the battery case due to the lengthening of the positive and negative electrode plates, and the amount of electrolyte solution injected We could not secure enough. As a result, the DSC pulse discharge characteristic is low. On the other hand, in the battery c6 in which the theoretical capacity per unit area was increased to 75 mAh / cm ² , the thickness of the positive electrode was excessive, and the facing area between the positive and negative electrodes was insufficient. Yes.

Example 4
In Example 4, the mass ratio of elements to be alloyed with lithium of the negative electrode plate was examined. As shown in Table 5, Sn, Mg, Zn, Bi, and Al were used as alloying elements, and a negative electrode plate was prepared in which the addition ratio of each element with respect to the mass of the entire lithium alloy was changed. Then, the subsequent battery constituent conditions were the same as in Example 1, and batteries d1 to d25 corresponding to the respective negative electrode plates were produced.

  Table 5 summarizes the results of performing aging and preliminary discharge on these batteries under the same conditions as described above, and then performing the performance evaluations (1) and (2) above. Here, each test was carried out in the form of obtaining an average value with the number of batteries n = 5. All the results are indexed with the performance value of the comparative battery a6 in Example 1 as 100 (reference).

  From Table 5, it can be seen that the mass ratio of elements to be alloyed with lithium in the negative electrode plate is 0.1 to 3% with respect to the total mass of the negative electrode plate (mass excluding leads for collecting current). . In batteries d1, d6, d11, d16, and d21 having a mass of alloying elements as small as 0.05%, it is difficult to obtain the effect of reducing the coating on the negative electrode surface, and the DSC pulse discharge characteristics are poor. Conversely, batteries d5, d10, d15, d20, and d25, which have a large alloying element mass of 3.5%, also have a relatively low ratio of lithium as the negative electrode active material. As an absolute capacity).

(Example 5)
In Example 5, in order to obtain knowledge about the type of carbon conductive material, the carbon conductive material shown in Table 6 was used, and the other conditions were all the same as in the case of the battery a1 of Example 1 (Sn alloy for the negative electrode). Batteries e1 to e6 corresponding to the respective carbon conductive materials were prepared.

  Table 3 summarizes the results of performing aging / preliminary discharge on these batteries under the same conditions as described above, and then performing the performance evaluations (1) and (2) above. Here, each test was carried out in the form of obtaining an average value with the number of batteries n = 5. All the results are indexed with the performance value of the comparative battery a6 in Example 1 as 100 (reference).

From Table 6, it is clear that it is desirable to use a carbon conductive material having a BET specific surface area of 300 m ² / g or more. In the batteries e1, e2, and e3 using carbon conductive materials having a BET specific surface area of less than 300 m ² / g, it is difficult to impregnate the positive electrode with an electrolytic solution, and the characteristics are low, mainly in DSC pulse discharge.

(Example 6)
In Example 6, in order to obtain knowledge about the mass mixing ratio of iron disulfide and the carbon conductive material in the positive electrode mixture, the positive electrode mixture having the mass mixing ratio shown in Table 7 was used. As in the case of the battery a1 of Example 1 (using Sn alloyed lithium as the negative electrode), batteries f1 to f5 corresponding to the respective mass mixing ratios were produced.

  Table 7 summarizes the results of performing aging / preliminary discharge on these batteries under the same conditions as described above, and then performing the performance evaluations (1) and (2) above. Here, each test was carried out in the form of obtaining an average value with the number of batteries n = 5. All the results are indexed with the performance value of the comparative battery a6 in Example 1 as 100 (reference).

  From Table 7, it is clear that the range of 97/3 to 93/7 is appropriate for the mass mixing ratio of the iron disulfide and the carbon conductive material in the positive electrode mixture. In the battery f1 having a mass mixing ratio of 98/2 and a small ratio of the carbon conductive material, it is difficult to ensure the DSC pulse discharge characteristics. Further, in the battery f5 having a mass mixing ratio of 92/8 and a small ratio of iron disulfide, it is difficult to ensure 100 mA continuous discharge characteristics (absolute battery capacity).

(Example 7)
Here, the skeleton shape of the diamond (diamond) expanded metal was examined. An expanded metal made of aluminum and having the shape parameters shown in Table 8 was prepared, and all other conditions were the same as in the case of the battery a1 of Example 1 (using Sn alloyed lithium for the negative electrode). A battery corresponding to expanded metal was constructed. At this time, it is difficult to secure a sufficient amount of the positive electrode mixture (g4, g8, g9, g13), and the positive electrode plate is cut when the electrode group is wound (g1, g5). Were present. These results are summarized in Table 8.

  Table 9 summarizes the results of performing the aging / preliminary discharge under the same conditions as described above, and then performing the performance evaluations (1) and (2) above on the batteries that could be configured as intended. Here, each test was carried out in the form of obtaining an average value with the number of batteries n = 5. All the results are indexed with the performance value of the comparative battery a6 in Example 1 as 100 (reference).

  From Table 9, the thickness T is 0.1 to 0.15 mm, the step width W is 0.2 to 0.3 mm, the center distance LW in the long direction is 2 to 3 mm, and the center distance SW in the short direction is It can be seen that a range of 0.8 to 1.8 mm is desirable. In g12 in which the center distance LW in the long direction is 3.5 mm and in g16 in which the center distance SW in the short direction is 2 mm, the active metal is located away from the skeleton because the expanded metal has a large pore diameter. It is assumed that it is difficult to maintain current collection from the particles and the discharge characteristics are not improved.

  As described in detail above, according to the present invention, it is possible to provide an iron disulfide / lithium primary battery having a high capacity and an excellent high-load discharge characteristic.

(Other embodiments)
The embodiments and examples described above are examples of the present invention, and the present invention is not limited to these examples. For example, in the above embodiment, the expanded metal is made of aluminum, but the same discharge characteristics can be obtained by using stainless steel. In particular, as described in Example 7, it is inferred that it is possible to avoid the breakage of the positive electrode plate during the winding configuration of the electrode group by using an expanded metal made of stainless steel stronger than aluminum. Is done.

In Example 5, ketjen black or specific carbon black was used as the carbon powder having a BET specific surface area of 300 m ² / g or more. However, the same effect can be obtained with carbon nanotubes, carbon nanofibers and the like having a specific surface area. It is done. Further, it is considered that a similar effect can be obtained even if a conductive material in a form mixed with other carbon powder is used mainly with carbon powder having a BET specific surface area of 300 m ² / g or more (50% or more). .

  Further, the element to be alloyed with lithium of the negative electrode is not limited to one kind, and may be alloyed in addition to two or more kinds of lithium.

  Furthermore, in the above embodiment, the AA size cylindrical battery is used, but the present invention itself is not limited to this, and is appropriately used for other sizes of cylindrical batteries, prismatic batteries, and the like. It is possible.

  As described above, the iron disulfide / lithium primary battery according to the present invention has a high capacity and an excellent high-load discharge characteristic, and is used for electronic games, toys and the like including digital still cameras. It is optimal as a 1.5V class primary battery.

1 Positive Plate 2 Negative Plate 3 Separator
4 Positive lead
5 Negative lead
6 Upper insulation plate
7 Lower insulation plate
8 Sealing plate
9 cases

Claims (5)

A positive electrode plate using iron disulfide as a positive electrode active material, a negative electrode plate using metal lithium as a negative electrode active material, and a separator, and the separator is sandwiched between the positive electrode plate and the negative electrode plate. A rotating iron disulfide / lithium primary battery,
The positive electrode plate includes a positive electrode mixture in which iron disulfide, a carbon conductive material, and a binder are mixed, and an expanded metal. The positive metal mixture is filled in an opening of the expanded metal, and the expanded metal Holding the mixture,
The porosity of the positive electrode plate is 25% or more and 35% or less,
The iron disulfide / lithium primary battery, wherein the negative electrode plate is lithium alloyed with one or more elements selected from Sn, Mg, Zn, Bi and Al. The iron disulfide / lithium primary battery according to claim 1, wherein a theoretical capacity per unit area of the positive electrode plate is 35 mAh / cm ² or more and 70 mAh / cm ² or less.   2. The iron disulfide / lithium primary battery according to claim 1, wherein a total mass of elements alloyed with lithium in the negative electrode plate is 0.1% or more and 3% or less with respect to a total mass of the negative electrode plate. The carbon conductive material includes carbon powder having a BET specific surface area of 300 m ² / g or more, and a mass mixing ratio of iron disulfide and the carbon conductive material in the positive electrode mixture is from 97/3 to 93/7. The iron disulfide / lithium primary battery according to 1.   The expanded metal is made of aluminum or stainless steel, the mesh shape is rhombus, the plate thickness T is 0.1 mm to 0.15 mm, the step width W is 0.2 mm to 0.3 mm, and the mesh length is long. The iron disulfide / lithium primary battery according to claim 1, wherein the center-to-center distance LW is 2 mm to 3 mm, and the center-to-center distance SW in the short direction of the mesh is 0.8 mm to 1.8 mm.

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