JP4129952B2 - Non-aqueous electrolyte battery - Google Patents

Description

  The present invention relates to a non-aqueous electrolyte battery, and more particularly to a high-capacity, safe and reliable cylindrical non-aqueous electrolyte battery suitable for use at medium loads and below.

  As the cylindrical non-aqueous battery, there are widely known bobbin type batteries for high loads such as memory backup and light loads, and wound batteries for heavy loads such as camera power supplies. The former bobbin type batteries are lithium manganese batteries and lithium thionyl chloride batteries, but they can be manufactured at a low cost with a simple structure, and can be filled with many active materials. Since the electrode area is small and the load characteristics are inferior, there is a disadvantage that the capacity is reduced when discharging with a large current is performed.

  The latter type of heavy load characteristic wound battery has been commercialized as a lithium manganese battery or a lithium fluorinated graphite battery. This type of battery has the advantage that a large electrode area can be secured and a large discharge capacity can be taken out even when discharged with a large current because a spiral electrode body formed by winding a thin long electrode is used as a battery element. is there. However, since many separators and current collectors that do not directly contribute to improving battery characteristics are provided in the electrode body, the filling amount of the active material has to be reduced, and it is inevitable that the battery capacity is reduced. In addition, while a large current can be taken out, there is a disadvantage in that when an abnormality such as a short circuit occurs, heat generation is severe and there is a risk of ignition, various safety measures are required, the battery structure is complicated, and the manufacturing cost increases. is there.

  Due to recent diversification of applied devices, not only light load applications such as memory backup, heavy load applications such as cameras, but also medium load applications such as data transmission and reception are increasing. There has been a demand for the development of a battery that can be used. Therefore, Patent Documents 1 and 2 propose a battery in which a battery element is an electrode winding body in which a thick electrode is wound several times. According to a battery using such an electrode winding body as a battery element, the use of a thick electrode reduces the amount of separators and current collectors used as compared with a conventional heavy load battery, thereby filling the active material. Therefore, a high capacity battery can be obtained. Further, by preventing an extremely large current from flowing, a battery having excellent safety and reliability and excellent medium load characteristics can be obtained.

Japanese Patent Laid-Open No. 6-267583 (paragraph number 0017, FIGS. 1 and 3) JP-A-9-190836 (paragraph number 0019, FIG. 1)

  However, the positive electrode of the battery described in Patent Document 1 and Patent Document 2 is inferior in flexibility and flexibility because the positive electrode of the current collector made of nickel foam is filled with an active material mixture. . For this reason, if the thickness dimension of the positive electrode is increased to, for example, 0.7 mm or more, it is unavoidable that the positive electrode is cracked or the active material is dropped during winding, and there is a risk of causing poor conductivity or short circuit.

  For batteries with a spiral electrode body made by winding a thin long electrode, the positive electrode is created by pressing the active material mixture on the current collector network or applying the active material mixture to the metal foil. is doing. However, even in such a positive electrode configuration, if the thickness dimension of the positive electrode is increased, it is inevitable that the positive electrode will be cracked or the active material will fall off during winding.

  Therefore, the present inventors, as shown in FIG. 1 and FIG. 3C of the present invention, two positive electrode sheets 20, 21 formed by forming a positive electrode mixture into a sheet shape, and the positive electrode sheets 20, 21 It has been found that the positive electrode 3 is constituted by the current collector 22 interposed therebetween. According to this, the flexibility and flexibility of the positive electrode 3 are favorably ensured as compared to a single-piece positive electrode in which a gap of a current collector made of nickel foam of a conventional form is filled with an active material mixture. it can. That is, since the positive electrode 3 is divided into two independent and separate positive electrode sheets 20 and 21 and a current collector 22, the thickness of the positive electrode sheets 20 and 21 per sheet can be small. Improvements in flexibility and flexibility can be expected.

  However, even when the positive electrode configuration as described above is adopted, if the thickness dimension of the positive electrode sheets 20 and 21 is increased to 0.7 mm or more, the composition condition and density of the positive electrode mixture constituting the positive electrode sheets 20 and 21 are increased. It has been found that unless the conditions and the like are optimized, the flexibility and flexibility of the positive electrode sheets 20 and 21 are poor, and winding with a desired winding diameter (winding diameter of 4 mm or less) becomes difficult. When the flexibility and flexibility of the positive electrode sheets 20 and 21 are thus reduced and the rollable diameter is increased, the winding center portion (C: see FIG. 1) is increased. In order to insert the rotating body 6, the length of the positive electrode sheets 20 and 21 must be reduced, and as a result, the amount of active material in the outer can 2 is reduced and the discharge capacity is reduced. . Further, if the density of the positive electrode sheets 20 and 21 is too small, the filling amount of the positive electrode active material is reduced, resulting in a decrease in discharge capacity. Conversely, if the density is excessive, the flexibility and flexibility of the positive electrode sheet are reduced. Becomes defective.

  An object of the present invention is to provide a conductive assistant contained in a positive electrode mixture in a non-aqueous electrolyte battery having a battery element formed by winding a sheet-like positive electrode having a large thickness and a short sheet together with a negative electrode and a separator. An object of the present invention is to provide a non-aqueous electrolyte battery excellent in discharge characteristics under a medium load by obtaining the blending ratio of the agent and the optimum value range of the positive electrode sheet density.

In the present invention, as shown in FIG. 2, an electrode winding body 6 in which a sheet-like positive electrode 3 and a negative electrode 4 are wound through a separator 5 in a bottomed cylindrical outer can 2 having an upper opening. And a non-aqueous electrolyte battery having a cylindrical shape. As shown in FIG. 1, the electrode winding body 6 has positive and negative electrodes 3 and 4 so that the number of windings defined by the winding start end and winding end of the positive electrode is 1.5 or more and 4 or less. The separator 5 is wound and formed into a substantially cylindrical shape as a whole. The positive electrode 3 includes two positive electrode sheets 20 and 21 formed by forming a positive electrode mixture containing a positive electrode active material, a conductive additive and a binder into a sheet having a thickness of 0.7 mm or more and 2 mm or less, and these positive electrodes A current collector 22 interposed between the sheets 20 and 21, and the two positive electrode sheets and the current collector are divided, or the two positive electrode sheets and the current collector The body is fixed only at a portion corresponding to the winding start end, and is divided at other portions.

In addition, in the present invention, carbon black having a specific surface area of 400 m ² / g or more and 2000 m ² / g or less is used as a conductive additive. The blending ratio of carbon black in the positive electrode mixture is 2.0 wt% or more and 4.0 wt% or less. The density of the positive electrode sheets 20 and 21 is set to 2.2 g / cm ³ or more and 2.7 g / cm ³ or less.

  Specifically, in the case of a lithium manganese battery, the positive electrode active material is preferably manganese dioxide, and the negative electrode 4 is preferably metallic lithium.

  The carbon black is preferably ketjen black.

In the nonaqueous electrolyte battery of the present invention, carbon black having a specific surface area of 400 m ² / g or more and 2000 m ² / g or less is used as a conductive additive contained in the positive electrode mixture constituting the positive electrode sheets 20 and 21. The optimum blending ratio of carbon black in the positive electrode mixture was 2.0 wt% or more and 4.0 wt% or less. In addition, the optimum density of the positive electrode sheets 20 and 21 was set to 2.2 g / cm ³ or more and 2.7 g / cm ³ or less.

Here, carbon black having a specific surface area of 400 m ² / g or more was used as the conductive auxiliary agent. When graphite or carbon black having a specific surface area of less than 400 m ² / g was used, the flexibility of the positive electrode sheet was improved. Because it is not obtained. When the specific surface area of the carbon black exceeds 2000 m ² / g, the negative electrode is liable to wither during battery discharge. In addition, carbon black having a specific surface area of 2000 m ² / g or more is bulky, and there is a disadvantage that the sheet density of the positive electrode does not increase and the filling property is lowered.

When the blending ratio of carbon black in the positive electrode mixture is less than 2.0 wt%, the effect of improving the flexibility and flexibility of the positive electrode sheets 20 and 21 due to the adoption of carbon black as described above is obtained. It cannot be obtained well. When the blending ratio exceeds 4.0 wt%, the positive electrode active material is reduced, which causes a reduction in discharge capacity. If the density of the positive electrode sheets 20 and 21 is less than 2.2 g / cm ³ , the flexibility and flexibility of the positive electrode sheets 20 and 21 can be secured well, but the filling amount of the positive electrode active material decreases, and the battery The discharge capacity is reduced. If the density of the positive electrode sheets 20 and 21 exceeds 2.7 g / cm ³ , the flexibility and flexibility of the positive electrode sheets 20 and 21 become poor and the rollable diameter becomes large. Become. For this reason, the length dimension of the positive electrode sheets 20 and 21 must be reduced, and the filling amount of the positive electrode active material is reduced, so that the discharge capacity is reduced.

  As the carbon black, ketjen black is most suitable, and the above-mentioned purpose can be easily achieved.

  1 to 3 show a nonaqueous electrolyte battery according to an embodiment of the present invention. In FIG. 2, the nonaqueous electrolyte battery 1 includes a bottomed cylindrical outer can 2 having an upper opening, a positive electrode 3 and a negative electrode 4 loaded in the outer can 2, and an upper opening of the outer can 2. It consists of the sealing structure to seal. The positive electrode 3 and the negative electrode 4 are accommodated in the outer can 2 together with the electrolytic solution as an electrode winding body 6 that is wound through a separator 5. The outer can 2 is made of iron or stainless steel.

  The sealing structure includes a cover plate 8 fixed to the inner peripheral edge of the upper opening of the outer can 2 and a terminal body attached to an opening formed in the center of the cover plate 8 via a rubber insulating packing 9. 10 and an insulating plate 11 disposed below the lid plate 8. The insulating plate 11 is formed in a round plate shape that opens upward with an annular side wall 13 standing on the periphery of the disk-shaped base portion 12, and a gas passage 14 is opened at the center of the base portion 12. Yes. The cover plate 8 is fixed to the inner peripheral edge of the upper opening of the outer can 2 with a crimp seal via laser welding or packing while being received by the upper end of the side wall 13. The lid plate 8 or the can bottom 2a of the outer can 2 can be provided with a thin portion, and a vent can be provided as a countermeasure when the internal pressure suddenly increases. The positive electrode 3 and the lower surface of the terminal body 10 are connected by a positive electrode lead body 15, and the negative electrode 4 and the inner surface of the outer can 2 are connected by a negative electrode lead body 16.

  As shown in FIG. 1, the electrode winding body 6 is positive so that the number of windings defined by the winding start end S and winding end E of the positive electrode 3 is 1.5 or more and 4 or less. -It is formed by winding the negative electrodes 3 and 4 and the separator 5, and is formed in a substantially cylindrical shape as a whole. FIG. 1 shows a form in which the number of wrinkles is about 1.6. The positive electrode 3 includes two positive electrode sheets 20 and 21 having the same thickness dimension, and a current collector 22 interposed between the positive electrode sheets 20 and 21. The positive electrode sheets 20 and 21 and the current collector 22 are wound in a state where only the winding start end S is fixed (see FIG. 3C).

  Each of the positive electrode sheets 20 and 21 is formed by forming a positive electrode mixture composed of a positive electrode active material, a conductive additive, and a binder into a sheet shape having a thickness dimension of 0.7 mm or more and 2 mm or less. Examples of the positive electrode active material include manganese dioxide, carbon fluoride, lithium cobalt composite oxide, and spinel type lithium manganese composite oxide.

  As the binder of the positive electrode 3, a polytetrafluoroethylene dispersion, a powdery polytetrafluoroethylene, a rubber-based binder, or the like can be used. However, it is preferable to use a polytetrafluoroethylene dispersion.

  As the current collector 22, a plain woven wire mesh made of stainless steel 316, 430, 444, or the like, an expanded metal, a lath mesh, a punching metal, a foil, or the like can be used.

  The negative electrode 4 is formed in a thin plate shape (foil shape), and examples of the material include lithium metal, alloys such as lithium and aluminum, and carbon materials such as graphite. As shown in FIG. 1 and FIG. 3 (b), the negative electrode 4 is formed by laminating two short and long negative electrodes 4 a and 4 b and winding them together with the positive electrode 3 and the separator 5 to form an electrode. A wound body 6 is produced.

As an electrolytic solution, a solvent in which LiPF ₆ , LiClO ₄ , LiCF ₃ (CF ₃ SO ₂ ) ₂ NLi or the like as a solute is dissolved in 0.3 to 1.5 M / l, such as DME or the like in a cyclic carbonate such as PC or EC. An electrolytic solution in which a chain carbonate such as a chain ether or dimethyl carbonate is mixed is used.

  As the separator 5, a nonwoven fabric such as PP, PE, PET, PBT, or PPS, a microporous film, or the like can be used.

  The electrode winding body can be manufactured by the procedure as shown in FIG. First, as shown in FIG. 3 (a), the separator 5 is wound around the winding core 25 in half and wound once. Next, as shown in FIG. 3 (b), the negative electrode 4 is inserted from the single layer portion of only the short length 4a toward the core 25, and is wound once with the separator 5 (see FIG. 3 (c)). Subsequently, as shown in FIG. 3C, the positive electrode 3 is placed on the negative electrode 4 through the separator 5 and wound around the winding core 25. The positive electrode 3 is wound from the side of the winding start end S to which both the positive electrode sheets 20 and 21 and the current collector 22 are fixed, and is placed on the long negative electrode 4b via the separator 5 It is beaten by. The positive and negative electrodes 3 and 4 and the separator 5 are wound so that the number of windings defined by the winding start end S and the winding end E of the positive electrode 3 is 1.5 or more and 4 or less. After winding is completed, the separator 5 covers the outermost periphery. The winding end E of the separator 5 is fixed with a fixing tape. From the above, the electrode winding body 6 having the form shown in FIG. 1 can be obtained. The winding core 25 has an elliptical shape as a whole. Therefore, a substantially elliptical winding center portion C without the positive and negative electrodes 3 and 4 is formed at the center of the electrode winding body 6 as shown in FIG. .

  Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In this embodiment, a CR battery will be described as an example.

Example 1
<Production method of positive electrode>
(Formulation) 2% by weight of ketjen black as a conductive assistant and 94% by weight of manganese dioxide (manufactured by Tosoh Corporation: HC-9) as a positive electrode active material are mixed for 5 minutes in a dry manner using a planetary mixer. After that, 4% by weight of polytetrafluoroethylene dispersion (PTFE: manufactured by D-1 Daikin Kogyo Co., Ltd.) as a binder was added in a diluted state in water, and was mixed for 2 minutes in a wet manner. The water content in the compounding agent was 25 to 30 with respect to the solid content of 100. The specific surface area of this ketjen black was 1270 m ² / g.

(Sheet) Rolling with a roll at a press pressure of 7 tons / cm, a roll interval of 0.4 mm, and a rotation speed of 10 rpm, using a roll of 250 mm in diameter with the mixed compounding agent, adjusting the roll temperature to 130 ± 5 ° C. The sheet was made. The compounding agent (preliminary sheet) that passed through the roll was dried at 105 ° C. ± 5 ° C. until the residual moisture became 2% or less. Next, the dried preliminary sheet was pulverized for 50 seconds using a pulverizer.

  The pulverized material was formed into a sheet by a roll again. The interval between the rolls was adjusted to 0.6 ± 0.05 mm, the roll temperature was 120 ± 10 ° C., the press pressure was 7 ton / cm, and the sheet was formed at a rotation speed of 10 rpm to obtain a positive electrode sheet having a thickness of 1.0 mm. It was.

  As described above, two positive electrode sheets 20 and 21 (see FIG. 1) for the inner periphery and the outer periphery were prepared. The positive electrode sheet 20 for the inner periphery was cut into a width of 37 mm and a length of 51 mm. The positive electrode sheet 21 for the outer periphery was cut into a width of 37 mm and a length of 62 mm.

(Current Collector) A lath net made of stainless steel 316 (manufactured by Nikken Lass) was used as the current collector 22. The lath net was cut into a width of 34 mm and a length of 56 mm, and a positive electrode lead body 15 made of a stainless steel ribbon having a thickness of 0.3 mm and a width of 3 mm was attached to the central portion in the length direction by resistance welding. After applying carbon paste (manufactured by Nippon Graphite Co., Ltd.) to the current collector 22 to such an extent that the mesh of the mesh is not broken, specifically, 4 mg / cm ² per current collector area, 2 under a heating temperature condition of 105 ° C. ± 5 ° C. Dried for more than an hour.

  Next, as shown in FIG. 3 (c), the two positive electrode sheets 20 and 21 are integrated with the current collector 22 interposed therebetween to fix only one end in the length direction. did. Specifically, the two positive and negative electrode sheets 20 and 21 for inner and outer periphery are set so that one end in the length direction is aligned and the end of the current collector 22 does not protrude from the positive electrode sheets 20 and 21. In this state, the three members were integrated by press-bonding 3 to 10 mm from the end in the length direction with a press. Subsequently, the positive electrode sheets 20 and 21 and the current collector 22 were dried with hot air at 250 ° C. ± 10 ° C. for 6 hours to obtain the positive electrode 3. Here, the integration of the positive electrode sheets 20 and 21 and the current collector 22 is a problem in work, and the independent positive electrode sheets 20 and 21 and the current collector 22 are integrated at the time of winding. There is no problem in characteristics.

<Negative Electrode Production Method> The negative electrode 4 was obtained by cutting a lithium foil having a width of 37 mm and a thickness of 0.3 mm into 46 mm and 96 mm, excluding 10 mm from one end of the short side foil 4a, and overlapping 36 mm with the long side foil 4b. And crimped. The negative electrode lead body 16 was formed by embossing one end of a nickel ribbon having a thickness of 0.1 mm and a width of 3 mm, and was fixed by being sandwiched between two foils.

<Assembly method> A microporous separator (Hypore made by Asahi Kasei Co., Ltd.) made of PE having a width of 44 mm and a thickness of 0.025 mm is cut into 220 mm and sandwiched between two cores 25 as shown in FIG. I rolled one lap. Next, as shown in FIGS. 3 (b) and 3 (c), the lithium metal foil of the negative electrode 4 having a single length of 10 mm is turned to the core 25 side and wound around the separator 5 at the same time, and then the positive electrode sheet 20 -The side to which 21 was fixed was placed on the core 25 side and wound. After winding, the separator 5 covered the outermost periphery, and the winding end portion of the separator 5 was fixed with a fixing tape. From the above, an electrode winding body 6 as shown in FIG. 1 was obtained.

  A PP insulating plate with a thickness of 0.2 mm is inserted into the bottom of the outer can 2 (inner diameter 16.5 mm) made of nickel-plated iron can, and the electrode winding body 6 is placed on the positive and negative lead bodies 15. 16 was inserted with the posture facing upward. The negative electrode lead body 16 was resistance welded to the upper inner surface of the outer can 2. The positive electrode lead body 15 was resistance welded to the lower surface of the terminal body 10 after inserting the insulating plate 11. At this point, the insulation resistance was measured and it was confirmed that there was no short circuit.

As an electrolytic solution, 3.3 ± 0.1 ml of 0.5 M LiClO ₄ / (PC + DME = 1: 2) was injected into the outer can 2. The injection was divided into three times, and the whole amount was injected under reduced pressure in the final step. After injection of the electrolyte, the lid plate 8 was sealed by fitting and laser welding. Thus, a nonaqueous electrolyte battery according to Example 1 was obtained.

(Post-processing: preliminary discharge, aging)
The sealed battery was pre-discharged with a resistance of 1Ω for 30 seconds, stored at 45 ° C. for 24 hours, and then subjected to secondary pre-discharge for 3 minutes at a low current of 1A. The battery after the preliminary discharge was aged at room temperature for 7 days, and the open circuit voltage was measured.

<< Example 2, Comparative Examples 1 to 4 >>
Example 2 and Comparative Examples 1 to 4 are the same as Example 1 except that the proportions of the positive electrode active material, the conductive additive and the binder constituting the positive electrode mixture are as shown in Table 1 below. A positive electrode sheet was obtained.

  The positive electrode sheet having a thickness of 1 mm according to Examples 1 and 2 and Comparative Examples 1 to 4 was wound around a SUS rod with a 1 mm interval from φ3 to φ9 mm, and the number of φmm was examined. That is, the rollable diameter of each positive electrode sheet was examined. With this diameter that can be wound, an electrode winding body 6 that is as large as possible that can be inserted into the same outer can 2 (inner diameter: 16.5 mm) as in the first embodiment is prepared. And batteries according to Comparative Examples 1 to 4 were prepared. In addition, since the winding center part C will become large if the winding possible diameter becomes large, the length dimension of the positive electrode sheets 20 and 21 must be made small.

  The batteries according to Examples 1 and 2 and Comparative Examples 1 to 4 were discharged to 2.0 V at 20 ° C. and 5 mA, and the discharge capacity was measured. In addition, the discharge capacity was measured until the discharge voltage reached 2.0 V under the condition of 1 A for 3 seconds and 27 seconds OFF. The results are shown in Table 2.

  From Table 2, it can be seen that the amount of electricity loss increases when the rollable diameter is 5 mm or more. More specifically, from the comparison between Example 1 and Comparative Example 1, when the blending ratio of ketjen black contained in the positive electrode mixture is less than 2% by weight, the rollable diameter is increased, and the winding center portion is It must be large, and as a result, it is understood that it causes a capacity shortage. From comparison between Example 2 and Comparative Example 2, when the proportion of ketjen black exceeds 4% by weight, ketjen black is bulky, so the amount of positive electrode active material is reduced by that amount, and the amount of charged electricity is less. I understand that From Comparative Examples 3 and 4, when carbon black or graphite having a small specific surface area is used as the conductive auxiliary agent, the positive electrode sheet is easily cracked and the rollable diameter is as large as 6 mm, so the amount of charged electricity is small. I understand that. From the above, when the positive electrode 3 having the positive electrode sheets 20 and 21 formed by forming the positive electrode mixture into a sheet of 0.7 mm or more as in the present invention is used, the conductive assistant included in the positive electrode mixture is used. As the agent, it is preferable to use ketjen black having a large specific surface area, and the mixing ratio of ketjen black in the positive electrode mixture is preferably in the range of 2 to 4% by weight.

  Next, the positive electrode sheets 20 and 21 according to Examples 3 to 5 and Comparative Examples 5 and 6 were obtained in the same manner as in Example 1 except that the sheet density of the positive electrode sheets 20 and 21 was as shown in Table 3. It was. Table 3 shows the sheet density and porosity of each positive electrode sheet.

  The positive electrode sheets 20 and 21 having a thickness of 1 mm according to Examples 3 to 5 and Comparative Examples 5 and 6 are wound around a SUS rod having a 1 mm interval from φ3 to φ9 mm, and the rollable diameter of each positive electrode sheet 20 and 21 is examined. It was. With this diameter that can be wound, an electrode winding body 6 that is as large as possible that can be inserted into the same outer can 2 (inner diameter: 16.5 mm) as in the first embodiment is prepared. To 5 and Comparative Examples 5 and 6 were prepared. In addition, since the winding center part C will become large if the winding possible diameter becomes large, the length dimension of the positive electrode sheets 20 and 21 must be made small.

  The nonaqueous electrolyte batteries according to Examples 3 to 5 and Comparative Examples 5 and 6 were discharged to 2.0 V at 20 ° C. and 5 mA, and the discharge capacity was measured. In addition, the discharge capacity was measured until the discharge voltage reached 2.0 V under the condition of 1 A for 3 seconds and 27 seconds OFF. The results are shown in Table 4.

From Comparative Example 6, when the sheet density exceeds 2.7 g / cm ³ , the flexibility and flexibility of the positive electrode sheets 20 and 21 are impaired, and the rollable diameter becomes large. As a result, it can be seen that the discharge capacity is significantly reduced. From Comparative Example 5, it can be seen that when the sheet density is less than 2.2 g / cm ³ , the filling amount of the positive electrode active material is reduced, causing a problem that causes a reduction in discharge capacity. If the density of the positive electrode sheets 20 and 21 exceeds 2.7 g / cm ³ , the possibility / flexibility becomes poor, and the diameter that can be wound increases, so that the winding center C is inevitable. As a result, the length dimension of the positive electrode sheets 20 and 21 has to be shortened, and the filling amount of the positive electrode active material is reduced, resulting in a decrease in discharge capacity. From the above, when the positive electrode configuration as in the present invention is adopted, the blending ratio of ketjen black is 2 to 4% by weight, and the density of the positive electrode sheets 20 and 21 is 2.2 to 2.7 g / cm. It can be seen that the range of ³ is suitable.

  Next, the batteries according to Examples 6 to 8 and Comparative Examples 7 to 9 were prepared by changing the thickness dimension of the positive electrode sheets 20 and 21 to 0.6 to 3.5 mm as shown in Table 5.

  From Table 5, it can be seen that when the thickness dimension of the positive electrode sheets 20 and 21 is less than 0.7 mm, winding deviation occurs. Moreover, when the thickness dimension of the positive electrode sheets 20 and 21 exceeds 2 mm, it cannot be wound unless the winding diameter is increased, and as a result, it is understood that the filling biographical amount is reduced.

1 is a cross-sectional plan view of a nonaqueous electrolyte battery according to a first embodiment of the present invention. It is a vertical front view of the nonaqueous electrolyte battery of the present invention. It is a figure for demonstrating the preparation methods of an electrode winding body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Nonaqueous electrolyte battery 2 Exterior can 3 Positive electrode 4 Negative electrode 5 Separator 6 Electrode winding body 20 Positive electrode sheet 21 located on the inner circumference side Positive electrode sheet 22 located on the outer circumference side Current collector C Winding center E Spinning end S Winding start end of the positive electrode

Claims (3)

In a cylindrical outer can having a bottom opening, a cylindrical shape formed by accommodating a non-aqueous electrolyte and an electrode winding body obtained by winding a sheet-like positive electrode and a negative electrode through a separator A non-aqueous electrolyte battery,
The electrode winding body is obtained by winding the positive and negative electrodes and the separator so that the number of windings defined by the winding start end and winding end of the positive electrode is 1.5 or more and 4 or less. And is formed into a substantially cylindrical shape as a whole,
The positive electrode is formed by forming a positive electrode mixture containing a positive electrode active material, a conductive additive and a binder into a sheet having a thickness of 0.7 mm or more and 2 mm or less, and a space between these positive electrode sheets. And the two positive electrode sheets and the current collector are divided, or the two positive electrode sheets and the current collector are wound starting ends. It is fixed only at the part corresponding to the part, it is divided at other parts,
The conductive auxiliary agent is carbon black having a specific surface area of 400 m ² / g or more and 2000 m ² / g or less, and the mixing ratio of carbon black in the positive electrode mixture is 2.0 wt% or more and 4.0 wt% or less. And
The density of the said positive electrode sheet is 2.2 g / cm < ³ > or more and 2.7 g / cm < ³ > or less, The nonaqueous electrolyte battery characterized by the above-mentioned.   The non-aqueous electrolyte battery according to claim 1, wherein the positive electrode active material is manganese dioxide, and the negative electrode is metallic lithium. The non-aqueous electrolyte battery according to claim 1, wherein the carbon black is ketjen black.

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