JPS6154165A - Manufacture of chargable electrochemical device - Google Patents

Abstract

PURPOSE:To improve the charge and discharge characteristic of a chargable electrochemical device by bringing a metallic lithium plate into contact with a negative electrode which is not pulverized even when it abosrbs lithium until its electric potential becomes equal to that of metallic lithium and making these parts touch the liquid electrolyte. CONSTITUTION:First, a negative electrode 1 which is not pulverized even after absorbing lithium is prepared by subjecting a mixture principally composed of TiO2 to pressure molding. Next, after the negative electrode 1 is pressed and fixed to a sealing plate 4, a metallic lithium plate 2 is pressed and fixed to the sealing plate 4. And also, the negative electrode 1 and the lithium plate 2 are connected to a sealing plate 4 working as a current collector for both of these parts. After that, the thus obtained body is combined with a positive electrode 5 principally composed of MnO2, a separator 7 and a liquid electrolyte principally composed of LiClO4, thereby assembling a chargable battery. In this battery where the negative electrode 1 and the lithium plate 2 touch the electrolyte while contacting with each other, lithium can be completely absorbed into the negative electrode 1. Accordingly, it is possible to minimize impedance and increase the amount of charge and discharge.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing rechargeable electrochemical devices with high energy density, in particular negative electrodes.

Structure of conventional examples and their problems Non-aqueous electrolyte secondary batteries that use lithium as a negative electrode active material and carbon fluoride, manganese dioxide, etc. as positive electrode active materials have already been put into practical use and are widely used as power sources for various electronic devices. It is used. This type of non-aqueous electrolyte battery using lithium as a negative electrode is characterized by high voltage and high energy density. Therefore, development of secondary batteries is also actively progressing. However, it has not yet been put into practical use. The main reason for this is that the charging/discharging life is short and the charging/discharging efficiency is low. This is largely due to the negative electrode.

In other words, in the same way as used in -order batteries,
In a lithium negative electrode constructed by pressing a plate-shaped metallic lithium onto a screen-shaped current collector such as nickel, it is difficult to deposit the lithium dissolved into the electrolyte during discharge into the original plate-shaped lithium during charging. be. For example, due to charging, lithium is irregularly precipitated in the form of dendrites, which is separated from the electrode plate and is no longer used as an active material, or lithium precipitated in the form of dendrites
It penetrates the separator and contacts the positive electrode, causing a short circuit.

Various attempts have been made to improve these drawbacks of lithium negative electrodes. Among these methods, there is a method of using a certain type of metal or alloy as the negative electrode material, which has the function of absorbing lithium ions in the electrolyte during charging to form an alloy with lithium, and releasing lithium as ions into the electrolyte during discharge. considered the most promising.

Aluminum (USP 3.6
07,413), silver (JP-A-56-7386゜US
P4,31e, 777, USP4,330,601
), lead (Japanese Unexamined Patent Application Publication No. 2006-141869), tin, tin-lead alloy, etc. are known. These materials have the disadvantage that when the amount of lithium absorbed by charging increases, the negative electrode material becomes pulverized, making it impossible to maintain the shape of the electrode.

As described above, when the negative electrode metal and lithium are brought into contact with each other in the electrolyte, a reaction occurs within a limited range where the negative electrode is in contact with the electrolyte and lithium.

When aluminum is used as the negative electrode metal, pulverized LiAl is generated at the contact portion between the three, so the negative electrode metal collapses and cannot function as an electrode.

In the present invention, an alloy is used for the negative electrode that does not become pulverized even when lithium is occluded until the potential becomes equal to the potential of lithium metal in the electrolyte.

A negative electrode alloy that does not become pulverized even when lithium is occluded until the potential becomes equal to that of lithium metal can be confirmed by, for example, the following experiment.

Electrodes of the alloy to be tested and lithium electrodes containing more lithium than can be occluded in said alloy are charged with a non-aqueous electrolyte, for example 1 mol/l lithium perchlorate (L L
ClO4) is immersed in dissolved propylene carbonate, and the terminals of the two electrodes are connected via a load, for example a resistor of IKD. If left in this state, lithium will dissolve from the lithium electrode, a reaction will proceed in which lithium ions in the electrolyte will be occluded by the alloy, and current will flow through the load. In this way, the load is left in a state where no current flows, that is, until the potential of the alloy electrode becomes equal to the potential of the lithium electrode,
The purpose is to observe changes in the alloy electrode.

As described above, it goes without saying that a major premise for a negative electrode for a battery is that even if lithium is occluded in the negative electrode, pulverization does not occur.

JP-A-55-166871, JP-A No. 66-136462, and JP-A No. 56-147368 disclose Cu as a negative electrode that does not cause pulverization even when lithium is occluded.
A negative electrode is described in which an oxide such as O2TiO2 or Nb2O6, graphite as a conductive agent, and a fluororesin as a binder are mixed and pressure molded.

Furthermore, the present inventors have found that an alloy containing cadmium and/or zinc as an essential component and at least one selected from the group consisting of lead, tin, indium, and bismuth has a large lithium storage capacity and is We proposed that it has excellent discharge reversibility and is very promising as a rechargeable negative electrode.

When constructing a battery using these negative electrodes that do not become pulverized even when lithium is occluded, the simplest method is 'l
! As described in Japanese Patent Publication No. Sho 56-136462, a negative electrode assembly in which a negative electrode and lithium metal are bonded together,
This method involves placing the positive electrode and separator together in a battery container, then injecting electrolyte and sealing the container.
In the battery case, the negative electrode and lithium metal become short-circuited, and lithium should naturally be inserted into the negative electrode.

However, this method also has the following problems.

That is, even when the negative electrode and lithium metal were pressure-bonded and the electrolyte was injected, lithium was not completely occluded into the negative electrode.

FIG. 1(A) is a schematic diagram when TiO2 or an alloy used for the negative electrode 1' and lithium metal 2' are pressed together. In this state, when the negative electrode and lithium metal are placed in an electrolytic solution, some of the lithium is occluded in the negative electrode, as shown in Figure 1←) (3' in the figure indicates that lithium in the negative electrode is occluded). However, some of them were not occluded and were separated from the negative electrode. This is because the electrolyte infiltrates into the small gap between the crimped surfaces of the negative electrode and lithium metal, and because the gap between the negative electrode and lithium metal is extremely small in this gap, the resistance of the electrolyte is also small, making it stronger than the crimped area. Reactions such as dissolution of lithium metal and occlusion of lithium into the negative electrode occur.

Eventually, when even the lithium attached to the negative electrode reacts, there is no electronic conductivity between the negative electrode and the lithium metal, so the unreacted lithium metal remains without being occluded by the negative electrode.

In this way, when the negative electrode and lithium metal were simply pressed together, lithium was not completely occluded and remained unreacted. Due to the presence of this unreacted lithium, the charge/discharge capacity of the battery decreased.

Additionally, if lithium metal is pressed onto the negative electrode facing the positive electrode, unreacted lithium will become an obstacle to the movement of ions in the electrolyte between the positive and negative electrodes, resulting in an increase in battery impedance. It was also the cause.

It is also conceivable to place lithium on the surface of the negative electrode that is not facing the positive electrode, but as will be described later, this method does not provide sufficient charge/discharge characteristics of the battery.

For this reason, lithium must be placed on the negative electrode surface facing the positive electrode.

Furthermore, in the case of a battery made by spirally winding a negative electrode assembly with a negative electrode and lithium metal crimped together, a positive electrode, and a separator, the curvature of the winding is different on the inside and outside of the negative electrode assembly, so the crimped lithium There was also the problem of the metal coming off.

OBJECTS OF THE INVENTION The objects of the invention relate to a method for manufacturing a rechargeable electrochemical device, in particular to an assembly of the negative electrode thereof;
It is an object of the present invention to provide a method for manufacturing an electrochemical device with a large charge/discharge capacity and low impedance, and to demonstrate a highly reliable manufacturing method.

Composition of the Invention The present invention comprises a reversible positive electrode, a non-aqueous electrolyte containing lithium ions, a compound that occludes lithium ions in the electrolyte upon charging to form a compound with lithium, and releases lithium as ions into the electrolyte upon discharging. A method for manufacturing a rechargeable electrochemical device having a negative electrode that does not become pulverized even when lithium is occluded until the potential of the negative electrode becomes equal to that of lithium metal, and a positive electrode of the negative electrode. Place lithium metal on the surface facing the negative electrode current collector,
The negative electrode and the lithium metal are incorporated into an electrochemical device so as to have electron conductivity with a lithium metal current collector, and the electrolyte is brought into contact with the negative electrode and the lithium metal in the device. It is characterized by

Description of Examples [Example 1] As a negative electrode, a mixture consisting of 100 parts of TiO2, 20 parts of graphite, and 2 parts of poly(47-ethylene) by weight was pressure-molded to a diameter of iawn and a thickness of o and sm. I used the one I made. As shown in the cross-sectional view of the button-type battery in Figure 2, this negative @1
A lithium metal plate 2 with a diameter of 16mm and a thickness of 0.12M is bonded to the sealing plate 4 of the battery using 5US SOA, and a part of the lithium metal plate is connected to the sealing plate of the button type battery. It was crimped with pressure so that it would fit. At this time, the sealing plate of a button-type battery was used as a common current collector for the negative electrode and the lithium metal plate.

For the positive electrode 5, a mixture consisting of 100 parts of MnO2, 20 parts of acetylene black, and 20 parts of polytetrafluoroethylene in a weight ratio of 20 mm in diameter and 0.7 mm in thickness was used. A pressure-molded electrode plate was used and placed in case 6. Using a separator 7 made of a nonwoven fabric made of polypropylene, L z of 1 mol/l
After injecting ClO4 dissolved in a mixed solvent of propylene carbonate and dimethoxyethane at a volume ratio of 1:1 as an electrolyte, the chamber was sealed. T used for the negative electrode at this time
The amount of electricity that can be charged and discharged in No. 102 was 50 mAh, the amount of electricity that the press-bonded lithium metal could have was so mAh, and the amount of electricity that could be charged and discharged for the positive electrode was 100 mAh. The reason why such a compounding ratio was adopted is that the amount of electricity in the battery is determined by the negative electrode, so that the characteristics of the negative electrode can be clearly expressed.

After being left for 3 days after sealing, the battery was discharged at 2 mA until the battery voltage reached 1 V, and then charged at 2 mA until the battery voltage reached 2 V. Charge and discharge were repeated under the same conditions. The average voltage during discharge was 1.2v.

After sealing, all of the 1 lithium metal should be occluded in TlO2, which is the negative electrode, during the period of 3 days.

The open circuit voltage of a battery using a sealing plate as a common current collector for the negative electrode of the present invention and lithium metal is 3.4V immediately after sealing.
, the impedance was 32Ω.

After being left for 3 days, a potential difference of 15 V and 32 Ω appears between the positive electrode M n O2 and the lithium metal crimped to the current collector immediately after sealing.
This represents the potential difference between O2 and the negative electrode, TiO2, which occludes lithium. Furthermore, the reason why there was no change in impedance was because all of the lithium metal was occluded in the negative electrode.

On the other hand, as a conventional example, as shown in FIG. 3, a battery was also constructed in which lithium metal was simply crimped onto the negative electrode. Note that elements common to those in FIG. 2 are given the same numbers. However, since the lithium metal plate 3 has a different shape, it is 3' in Figure 3.
And so. The battery of the present invention is designated as A, and the battery with the conventional configuration is designated as B.
shall be. The negative electrode, lithium metal, positive electrode, etc. of battery B are all the same as those of battery A. The open circuit voltage of this B battery immediately after sealing is 3.4V, and the impedance is 32ρ and A
It is the same as the battery. However, after being left for 3 days and lithium was occluded in the negative electrode, the voltage was 1.5V, the same as the battery of the present invention, but the impedance was 136Q. When the battery is disassembled, it is found that in the battery A of the present invention, lithium is completely occluded in the negative electrode, whereas in the battery B with the conventional configuration, some lithium metal remains in an unreacted state. , this lithium metal was not in contact with the negative electrode and appeared to be floating. I think this is why the impedance has increased.

In addition, the discharge capacity after repeated charge/discharge cycles is the fifth
At cycle 1, battery B had 17 mAh compared to 42 mAh for battery A. This means that in battery A, 7% of the lithium initially charged in the battery is used for charging and discharging, while in battery B, about 40% of the lithium metal initially charged is used for charging and discharging. This is thought to be because while the remaining 60% is inserted into the negative electrode and is being charged and discharged, the remaining 60% is floating inside the battery and is not being charged or discharged.

As described above, as a method of making the sealing plate serving as a current collector for the negative electrode also serve as a current collector for lithium metal, it is also possible to reverse the positions of the negative electrode and lithium metal in FIG. 2.

However, although the impedance of the battery made by this method is equivalent to that of the battery of the present invention described in the previous example, when charging and discharging are repeated, the discharge capacity at the 5th cycle is 26 mAh, which is different from the conventional configuration. Although it was better than battery B, it was clearly smaller than battery A. The reason for this is that when lithium is occluded in the anode, it is not occluded uniformly, but the distribution of lithium occluded in the anode is uneven, such as the largest amount being occluded in the part of the anode near the lithium metal. It is estimated that In order to increase the charge/discharge capacity of a battery, it is considered desirable that a large amount of lithium be occluded on the surface of the negative electrode near the positive electrode.
It can be seen from the above results that it is desirable to arrange lithium on the surface of the negative electrode facing the positive electrode, as in the battery of Example A.

[Example 2] An alloy consisting of at least one selected from the group consisting of:

As mentioned above, these alloys had a large lithium storage capacity, did not become pulverized even when lithium was stored, and had excellent charge/discharge reversibility.

Sn and Pb of the conventional example and the above alloy components.

When In and Bi were used as the negative electrode of the above-mentioned experimental device, they were pulverized as lithium was occluded. On the other hand, Cd.

Although Zn was not pulverized, the amount of electricity flowing to the load was small. For the above alloys, Sn, Sn,
Pb, In, Bi are involved, and Cd.

It is thought that Zn plays the role of a binder to prevent pulverization.

Therefore, in order to construct a negative electrode with a large charge/discharge amount, Sn, P
It is preferable to use an alloy containing a large amount of B, In, and Bi. However, when lithium is occluded until the potential becomes equal to that of lithium, the amount of Cd and/or Zn must be at least 6% by weight to prevent pulverization, and furthermore, it is necessary to prevent pulverization due to repeated charging and discharging. or more than 10% by weight.

This will be explained in detail below.

As mentioned above, in the case of an alloy of Cd and at least one selected from the group of Sn, Pb, In, and Bi, the amount of J] is 10
Cd is required to be at least 80% by weight, but in order to increase the amount of charge and discharge as a negative electrode, the amount of Cd is preferably 80% by weight or less, and more preferably 1% by weight.
A preferable range is 0 to 40% by weight.

In the case of an alloy of at least two selected from the group Sn, Pb, In, and BiO and Cd, the amount of Cd is 1Q to 80% by weight,
Preferably it is 10 to 40% by weight.

A ternary alloy has better high rate charge/discharge characteristics than a binary alloy containing Cd. This is thought to be because lithium diffuses along the interface between phases in the alloy.

Furthermore, when at least one selected from the group of mercury, silver, antimony, and calcium is added to an alloy of at least one selected from the group of Sn, Pb, In, and Bi and Cd in a range of 20% by weight or less, the alloy becomes full. The amount of discharge increases.

i>il Among the alloys mentioned above, in the case of an alloy of at least IN and Cd selected from the group of Sn and Pb, it is inexpensive in terms of cost and has a large charge and discharge capacity.In the case of OSn Cd alloy and Pb-Cd alloy, the amount of Cd is is 10 to 80% by weight, preferably 1o to
Comparing the Sn-Cd alloy and the Pb-Cd alloy, which have a large charge/discharge amount in the range of 40% by weight,
The former is superior in high rate charge/discharge characteristics.

Comparing Sn and l-Pb, PbO is cheaper.

Therefore, by using a Pb-Sn-Cd alloy, it is possible to obtain a negative electrode that is inexpensive and excellent in high rate charging and discharging. In this case, the Cd content is 10-80M, preferably 10-40% by weight, and the Sn content is 20-30% by weight.
, the balance is PB, and the composition is good.When making an alloy negative electrode, the simplest method is to immerse a melon-shaped current collector made of copper, nickel, iron, stainless steel, etc. in a molten alloy. In this method, the current collector is coated with an alloy by pulling it up. At this time, in order to improve the compatibility between the current collector metal and the alloy, it is desirable that the alloy contains In. In has the ability to occlude and release lithium through charging and discharging, and when In is used, it becomes a negative electrode that is compatible with the current collector and has a large charge/discharge capacity. However, since In is expensive, it should be used in small amounts. In the Sn-In-Cd alloy, the Cd content ranges from 10 to soi, preferably from 10 to
A preferred example is a composition in which the amount of In is 3 to 10% by weight, and the balance is Sn. In the case of pb-In-Cd alloy, the amount of Cd and the amount of In are 5n80% by weight, preferably 1
0 to 40% by weight, the amount of In is preferably 3 to 1n% by weight, and the amount of Pb is 20 to 80% by weight, preferably 40 to 80% by weight.
% by weight is advantageous in terms of performance and cost.

When using an alloy of Zn and at least one selected from the group of Sn, Pb, In, and Bi in a nonaqueous electrolyte,
In order to prevent pulverization from occurring even when lithium is occluded until the potential becomes equal to that of lithium, Zn must be present in an amount of 10% by weight or more. Furthermore ((To prevent pulverization from occurring due to repeated charging and discharging of lithium occlusion and desorption, Z
n must be 15 times or more. As the amount of Zn increases, the amount of charge and discharge as a negative electrode decreases, so the amount of ZnO is preferably 80% by weight or less.

In the case of a B1-Zn binary alloy, the amount of Zn must be 1nwt% or more to prevent pulverization even when lithium is occluded, but in order to obtain sufficient charge-discharge characteristics, the amount of K is 60 to 8% by weight.
6% by weight is required.

5n-Zn alloy has good properties as a negative electrode when the Zn content is 16 to 80% by weight, and 30 to 60% by weight is particularly preferred.

In an alloy of Sn, Pb, In, Bi (7:1) and at least two selected from the group 1 and Zn, the amount of ZnO is preferably 20 to 80% by weight in order to increase the amount of charge and discharge.5n-In-
In Zn alloy, the weight ratio of Sn and In is 1/9 to 9/9.
In the o Sn P b Z n alloy, the weight ratio of Sn to pb is preferably 4/1 to 1/2.

Furthermore, in the Pb-In-Zn alloy, pb and In0
The weight ratio is preferably 3/1 to 1/9. B1 and Zn,
The remainder is at least one selected from the group of Sn, Pb, and In.
In the seed alloy, the amount of Zn is preferably 20 to 80% by weight,
The amount of Bi is desirably 50% by weight or less. Even in alloys containing Zn, alloys containing more Sn than PB are preferred in order to perform high rate charging and discharging. 5n-Pb-Zn
In the alloy, the amount of Zn is between 2Q and 80% by weight, preferably 3
0 to 60% by weight is good, and the amount of pb is 10 to 20% by weight.
It is preferable to use an alloy in which the balance is Sn.

In manufacturing a negative electrode, a method of coating a metal current collector with the alloy by immersing the metal current collector in a molten alloy is simple. At this time, in order to improve compatibility with the current collector, it is desirable to use an alloy containing In, as in the case of the Cd-based alloy. 5n-In-Znρ ■For gold, the amount of Zn is 2Q~80
The weight percentage is good, preferably 3Q to 60% by weight. I
It is preferable to use an alloy in which the amount of n is 3 to 1n'TVXi%, and the balance is Sn. In the Sn-Pb-In-Zn alloy, the amount of Zn is 20-80% by weight, preferably 30-60% by weight, the amount of Pbl'i1 is 10-20% by weight, and the amount of In is 3-1% by weight.
An alloy containing 0% by weight and the balance being Sn is preferable.

In the above example, an alloy containing at least one of Cd and Zn was described, but an alloy containing both may be used as well. In that case, the sum of the Zn and Cd contents must be 15 to 80 to prevent pulverization even when lithium is occluded until the potential is equal to that of lithium, and to prevent pulverization even after repeated charge/discharge cycles. % by weight, and from the viewpoint of charge/discharge capacity, the content of Cd is preferably 50% by weight or less. S
In the n-Zn-Cd ternary alloy, the sum of the Cd and Zn contents is 20 to 80% by weight, preferably 30 to 60% by weight.
, CD is preferably 10 to 20% by weight. pb-3n-C
In the d-Zn quaternary alloy, the sum of the Zn and Cd contents is 20
~80% by weight, preferably 30-60% by weight, Ccl
No [i (is 1Q to 20% by weight, Pb] amount is 10 to 2
An alloy containing 0 weight and 1% Sn and the balance is excellent in charging and discharging characteristics when used as a negative electrode. Also in the case of a quaternary alloy of Sn-In-Zn-Cd, the sum of the contents of Zn and Cd is 2Q to 8
o% by weight, preferably 30 to 60% by weight, the amount of Cd is 10 to 20% by weight, and the amount of In is 3 to 10% by weight, which has good properties as a negative electrode and is relatively inexpensive. pb
In the case of a six-element alloy of -3n -In -Zn -Cd, the sum of the contents of Zn and Cd is 20 to 80% by weight, preferably 3Q to 60% by weight, the amount of Cd is 10 to 20% by weight, and the content of Pb is 10 to 20% by weight.
An amount of 10 to 20% by weight, and an amount of In of 3 to 10% by weight have good properties as a negative electrode and are relatively inexpensive.

In this example, a method of manufacturing a battery using such an alloy as a negative electrode and winding it in a spiral shape will be described.

When winding the negative electrode alone or together with the positive electrode in a spiral,
Among the above alloys, alloys in which the sum of the contents of Sn, Pb, In, and Zn is 40% by weight or more are particularly soft and easy to roll into.

PI] An alloy with a composition of 70M, 25% by weight of Cd, and 5% by weight of In was melted, and a part of expanded nickel metal was immersed in it and pulled up to form a 14MX100
The alloy was solidified to a thickness of M and a thickness of ○-2M. In addition, the size 14 is attached to the exposed part of this extra band metal.
A lithium plate of mm x 100+nm and thickness of 0.4 nm was crimped to form an electrode as shown in Figure 4. In the figure, 8 is a nickel lead piece welded to the center of the nickel extended metal of the current collector. 1Q is a negative electrode alloy coated on the right half of the expanded metal, and 11 is a lithium metal plate crimped onto the left half of the expanded metal. Next, the expanded metal was bent from the center so that the lithium layer overlapped the alloy. This electrode is designated as C.

As a conventional example, an electrode was made by pressing a lithium plate of the same size onto an alloy made of the same size as described above. Let this electrode be d. In the electrode d, the nickel expanded metal is buried in the alloy, and the crimped lithium metal does not come into contact with the nickel expanded metal. therefore,
Nickel expanded band metal is not a current collector for lithium metal.

Furthermore, as a conventional example, electrode e has the same structure as C using Ad and lithium metals having the same dimensions as described above.

Electrode f having the same configuration as d was made.

The positive electrode was made by mixing TIS 21001 with acetylene black 10, F, and laMMl (l) and molding it on both sides of a titanium expanded metal.
A material with a thickness of 1 ml was used. The theoretical capacity of this positive electrode is 414 mAh.

Eight pieces of polypropylene nonwoven fabric were wrapped around the positive electrode, overlapped with the previous electrode, then spirally wound and placed in a battery case. After this, 1 mol/l of LIC was added as an electrolyte.
After injecting propylene carbonate in which IO4 was dissolved, the vessel was sealed. A battery using electrode C has C1 electrodes d, e, f.
The batteries using these are designated as E and F, respectively.

FIG. 5 shows the structure of battery C. 12 is ke, -su 1
The groove provided in the upper part of the terminal 14 is made of a synthetic resin seal plate, and an aluminum riveted terminal 15 is fixed in the center of the plate.
6. Positive electrode lead pieces 17 are welded to the lower part. 18 is a synthetic resin bottom insulating plate, 1 is case 1
This is a spiral-shaped electrode plate group incorporated in the electrode plate 3, which is a positive electrode 20 and a negative electrode assembly wrapped in a separator 7 and wound in a spiral shape. The positive electrode 20 has a titanium expanded metal 21 as a current collector and a titanium lead 17 welded to the end of the expanded metal.

In order to cause lithium to be absorbed into the negative electrode alloy in the battery,
After sealing, it was left for one day. After that, the battery was discharged with a current of s o mA until the battery voltage reached 0.8v, and the battery voltage decreased to 2.5v.
The charge/discharge cycle was repeated until the battery reached . FIG. 6 plots and shows the amount of electricity discharged in each cycle of batteries C-F.

Comparing C and D, C has a larger discharge capacity. Moreover, the impedance of C was smaller.

In the case of D, this is because the negative electrode and lithium are only crimped together when rolled into a spiral shape, so a part of the lithium peels off, and the crimped lithium is intercalated into the negative electrode from the crimped surface. This is thought to be because it appeared to be floating and remained unoccluded by the negative electrode.

Batteries E and F were almost impossible to charge and discharge.

When the battery was disassembled, in Battery E, the AI was almost in the form of mud, and the generated LiA3 was hardly collecting current. On the other hand, in battery F, although the A1 surface was muddy, a considerable amount of metal AI and lithium remained unreacted. This is because lithium separates from Al as K is occluded in AI.

As mentioned above, even when winding the negative electrode assembly in a spiral shape, the negative electrode current collector and the lithium current collector are used in common.
When electronic conductivity is achieved between the negative electrode and the lithium metal, the amount of charge and discharge of the battery increases.

In addition to using an electric current on the coplanar I, it is also extremely effective to directly weld the negative electrode current collector and the lithium metal current collector, or to weld the image current collector through a metal piece. .

As the positive electrode for constructing the rechargeable electrochemical device of the present invention, one having reversibility of charging and discharging is used. For example, Mo0TiS2. v6o13゜I Cr 30s + T i○2. WO3, TaS2.
It is a positive electrode that uses NaCr52 or the like as an active material.

If well-known carbonaceous electrodes such as graphite electrodes or activated carbon electrodes used in electric double layer capacitors are used, it can also be used as a memory backup power source.

As the non-aqueous electrolyte, an organic electrolyte is preferable.0 Part 4
Examples of single solvents include propylene carbonate, γ-butyrolactone, ethylene carbonate, 1゜2-dimethoxyethane, tetrano\hydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, etc., and lithium salts of solutes include L. z Clo 4. Lz
B F 4+ L I A s F L I SO
Well-known materials used in organic electrolyte batteries, such as s CF 3°6+ L IP Fe, can be used. These organic solvents.

The solutes are not limited to being used alone, and may be used in combination.

In addition to the alloys and TiO2 described in the examples, Nb2O5, Fe2o3. Although oxides such as WO2 are also effective, it is best to use alloys in terms of the amount of charge and discharge per volume of the negative electrode.

In the above embodiments, a negative electrode made of a specific oxide or alloy,
Although an electrochemical device combining a positive electrode and an electrolyte has been described, the present invention is not limited thereto.

Effects of the Invention As described above, in the present invention, by combining a negative electrode and a lithium alloy to form a negative electrode assembly, it is possible to create an electrochemical device with a large charge/discharge capacity and low impedance, and the industrial effects are It's large.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the changes when the negative electrode and lithium metal are placed in an electrolytic solution after pressure bonding, Fig. 2 is a cross-sectional view of a button-type battery according to an embodiment of the present invention, and Fig. 3 2 is a cross-sectional view of a conventional button-type battery, FIG. 4 is a schematic diagram of a negative electrode assembly of a spirally wound battery according to a different embodiment of the present invention, and FIG. FIG. 6 is a cross-sectional view of the assembled battery, and FIG. 6 is a cycle-discharge electricity characteristic diagram of the battery. 1... Negative electrode, 2... Lithium electrode, 4
...Sealing plate, 6...Positive electrode, 7...
・Separator, 8... Ex band metal, 9
...Nickel extract band metal, 1o...
...Alloy negative electrode, 11...Lithium metal. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 5
Figure 6 Figure il I 2 Ru a,

Claims (8)

[Claims] (1) A reversible positive electrode, a nonaqueous electrolyte containing lithium ions, and a negative electrode that occludes lithium ions in the electrolyte to form a compound with lithium upon charging, and releases lithium as ions into the electrolyte upon discharging. 2. A method for manufacturing a rechargeable electrochemical device comprising: a negative electrode that does not become pulverized even when occluding lithium until its potential becomes equal to that of lithium metal; A lithium metal is placed on the surface, and the negative electrode and the lithium metal are incorporated into an electrochemical device, with electronic conductivity between the negative electrode current collector and the lithium metal current collector. A method of manufacturing a rechargeable electrochemical device, comprising contacting an electrolyte with a negative electrode and lithium metal within the device. (2) A patent that includes the steps of spirally winding a negative electrode and lithium metal together with a separator and a positive electrode, incorporating the spirally wound electrode plate group into a device, and then injecting an electrolyte into the device. A method of manufacturing a rechargeable electrochemical device according to claim 1. (3) After incorporating the positive electrode into the device and injecting the electrolyte,
A method of manufacturing a rechargeable electrochemical device according to claim 1, wherein the negative electrode and lithium metal are incorporated into the device with a separator interposed between the negative electrode and the positive electrode. (4) Claim 1, characterized in that the negative electrode current collector and the lithium metal current collector are a common metal current collector.
Method of manufacturing a rechargeable electrochemical device as described in Section 1. (5) A method for manufacturing a rechargeable electrochemical device according to claim 1, characterized in that an alloy current collector and a lithium metal current collector are welded. (6) A reversible positive electrode, a non-aqueous electrolyte containing lithium ions, and a negative electrode that occludes lithium ions in the electrolyte to form a compound with lithium upon charging, and releases lithium as ions into the electrolyte upon discharging. 2. A method for manufacturing a rechargeable electrochemical device comprising: the negative electrode does not become pulverized even when lithium is occluded until its potential becomes equal to that of lithium metal; The negative electrode and lithium metal negative electrode assembly, which has electronic conductivity between it and the lithium metal current collector, are spirally wound together with a separator and a positive electrode, and then assembled into an electrochemical device, and then subjected to electrolysis. A method of manufacturing a rechargeable electrochemical device that injects a liquid into the device. (7) A method for manufacturing a rechargeable electrochemical device according to claim 6, wherein the negative electrode and lithium metal are plate-shaped and supported on a common metal current collector. (8) The rechargeable electrochemical device according to claim 6, wherein the negative electrode and the lithium metal are plate-shaped, and the negative electrode current collector and the lithium metal current collector are welded. Manufacturing method.