CN1128482C - Lithium ion battery and method of manufacture thereof - Google Patents

Abstract

The present invention aims to simply the fabrication of a lithium ion secondary battery and enhances production rate. The battery does not need a firm casing, is capable of realizing small size and light weight and having any shape and has the advantages of high structural strength and capability of ensuring high security performance and high performance. The method for fabricating the lithium ion secondary battery of the present invention comprises the following steps: a working procedure of partly stacking adhesive resin (6) at least containing part of plastic resin between an anode (3) and a cathode (5) and a working procedure of making the adhesive resin (6) undergo plastic deformation.

Description

Lithium ion battery and manufacturing method thereof

technical field

The present invention relates to lithium ion batteries. More specifically, it relates to a high-performance secondary battery that can have an arbitrary shape such as a thin type, and a method of manufacturing the same.

Background technique

There is an urgent need to reduce the size and weight of hand-held portable electronic devices, and the realization of this desire depends largely on the improvement of battery performance. In order to meet this need, studies to improve battery performance have been extensively conducted. Desired battery properties include high voltage, high energy density, high safety, and free shape design. Among conventional batteries, Li-ion batteries are the most promising secondary batteries in terms of high voltage and high energy density, and are still being studied to improve their performance.

Lithium ion batteries currently used have a positive electrode plate prepared by applying powder of lithium cobalt oxide or the like to a current collector, and a negative electrode plate similarly prepared by applying powder of a carbon material to a current collector. In order for these electrodes (ie, the positive and negative electrodes) to be used in lithium-ion batteries, there must be an ion-conducting layer that is not electronically conductive, through which lithium ions can move between the two electrodes. Typically, a separator made of a porous membrane such as polyethylene filled with an anhydrous electrolyte is embedded between electrodes as an ion-conducting layer.

As shown in FIG. 7, a rigid case 1 made of metal or the like is used to house a positive electrode 3, a negative electrode 5, and a separator 4 containing an electrolytic solution or the like. Without the casing 1, it will be difficult to integrate the positive electrode 3, the negative electrode 5 and the separator. If it is separated, the performance of the battery will be deteriorated. However, the casing 1 makes the battery heavy and cannot freely design its shape. Therefore, a battery that does not require the case 1 is now being developed. One of the problems in developing such a battery without the case 1 is how to combine the electrodes 3 and 5 with the separator 4 sandwiched therebetween and maintain this combination without applying external force.

Regarding this connection, U.S. Patent No. 5,460,904 discloses a method of forming an ion-conducting layer sandwiched between positive and negative electrodes, which teaches the use of a polymer mixed with a plasticizer of at least Part of it migrates into the electrolyte. However, the method disclosed in US Pat. No. 5,460,904 is not a preferred manufacturing method because it involves treatment of an organic solvent when forming an ion-conducting layer, steps and equipment for removing the organic solvent are necessary.

Contents of the invention

Therefore, in order to realize a practical thin lithium-ion battery, it is necessary to develop a battery structure and a manufacturing method thereof that can ensure efficient bonding of positive and negative electrodes and that can ensure sufficient structural strength and safety as a battery.

According to the manufacturing method of the first lithium-ion battery of the present invention, the battery comprises a positive electrode formed with a positive electrode active material layer, a negative electrode formed with a negative electrode active material layer, and they are immersed in the electrolyte, the method comprises the following steps: a step of partially laminating an adhesive resin including at least a part of a plastic resin between the positive electrode and the negative electrode; and a step of deforming the adhesive resin.

According to the second method of manufacturing a lithium ion battery of the present invention, in the above first method of manufacturing a lithium ion battery, the adhesive resin is deformed by applying a pressure capable of deforming the plastic resin or higher.

According to the first and second methods of the present invention, since the adhesive resin at least partially contains the plastic resin, (i) it is not necessary to dry each time when connecting the positive electrode and the negative electrode, (ii) it is not necessary to maintain the connected state. (iii) the process of deforming the adhesive resin does not need to be performed one by one, and can be completed at one time, (iv) the production equipment can be simplified and the productivity can be improved, (v) the deformation of the plastic resin can increase the amount of the adhesive resin and the normal , The contact area of the negative electrode improves the adhesive force, so that the obtained battery has sufficient high battery strength in practical use.

According to the third method for manufacturing a lithium ion battery of the present invention, in the above first method for manufacturing a lithium ion battery, the plastic resin is a thermoplastic resin. According to this method, since the adhesive resin at least partially contains a thermoplastic resin, production facilities can be simplified and productivity can be improved. In the case of abnormal conditions such as heat generation caused by a short circuit, the thermoplastic resin melts, causing the current to be interrupted. Therefore, a highly safe lithium ion battery can be obtained.

According to a fourth method of manufacturing a lithium ion battery of the present invention, in the above third method of manufacturing a lithium ion battery, the adhesive resin is deformed by heating.

According to the fifth method of manufacturing a lithium-ion battery of the present invention, in the above-mentioned fourth method of manufacturing a lithium-ion battery, the heating temperature is above a temperature at which the thermoplastic resin starts to flow.

According to the fourth and fifth methods, the flow of thermoplastic resin produces adhesive force. Not only the contact area between the positive and negative electrodes of the resin increases, but also the resin penetrates into the micropores on the surface to produce an anchoring effect. Therefore, a practical lithium ion battery with high adhesive strength can be obtained.

According to a sixth method of manufacturing a lithium ion battery of the present invention, in the above third method of manufacturing a lithium ion battery, the adhesive resin is deformed by applying ultrasonic waves under pressure. According to this method, since the resin is effectively deformed by applying ultrasonic waves, bonding can be achieved even at low pressure or low temperature. Also, since only the surface of the thermoplastic resin is selectively heated, bonding can be efficiently achieved.

According to the first lithium ion battery of the present invention, it is characterized in that it has a laminated electrode body, and the laminated electrode body includes a positive electrode with a positive electrode active material layer connected to a positive electrode collector, and a negative electrode connected to a negative electrode collector. The negative electrode of the active material layer, and an adhesive resin containing at least a part of a plastic resin disposed between the positive electrode and the negative electrode, wherein a void communicating the positive electrode and the negative electrode is formed in the adhesive resin. Because the adhesive resin at least partially contains plastic resin, the production equipment can be simplified and the productivity can be improved; the contact area between the adhesive resin and the positive and negative electrodes can be increased by deforming the plastic resin, and the adhesive force is improved, so that the obtained battery has a practical High enough battery strength in medium.

According to the second lithium ion battery of the present invention, in the above first lithium ion battery, the plastic resin is a thermoplastic resin. Since the adhesive resin at least partially contains a thermoplastic resin, production equipment can be simplified and productivity can be improved. In the case of abnormal conditions such as heat generation caused by a short circuit, the thermoplastic resin melts, causing the current to be interrupted. Therefore, a highly safe lithium ion battery can be obtained.

According to the third lithium ion battery of the present invention, in the above first lithium ion battery, the area of the void portion accounts for 30 to 90% of the entire area of the opposing surface of the positive electrode and the negative electrode. Since the gap between the positive and negative electrodes is filled with electrolyte, the resistance of ion conduction between the positive and negative electrodes is greatly reduced. In this way, it can be used in a highly charged state, and sufficient adhesive strength for practical use is ensured.

According to the fourth lithium ion battery of the present invention, in the above first lithium ion battery, the distance between the positive electrode and the negative electrode is 100 μm or less. Since the gap between the positive electrode and the negative electrode is filled with electrolyte, the resistance of ion conduction between the positive and negative electrodes is greatly reduced, so that it can be used in a highly charged state.

According to a fifth lithium ion battery of the present invention, in the above first lithium ion battery, there are a plurality of laminated electrode bodies. A small but stable and high-capacity Li-ion battery is available.

Description of drawings

1 is a schematic cross-sectional view illustrating a battery structure of a lithium ion battery according to an embodiment of the present invention;

Figure 2 schematically illustrates a method of applying an adhesive resin with an applicator according to one embodiment of the present invention;

3 is a schematic cross-sectional view of a battery illustrating a lithium ion battery according to an embodiment of the present invention;

Fig. 4, 5 and 6 are the schematic sectional views of the battery structure of the lithium-ion battery of other embodiments of the present invention;

7 is a schematic cross-sectional view of a battery structure of a conventional lithium ion battery.

Detailed ways

The present invention is applicable to a battery structure having a positive electrode, a negative electrode, and an ion-conducting layer sandwiched therebetween, although the embodiments described below for implementing the invention relate primarily to batteries of the single-electrode body type, i. laminated electrode body, but can also be applied to a laminated battery body having a plurality of such laminated electrode bodies.

FIG. 1 is a cross-sectional view illustrating a battery structure of a lithium ion battery according to an embodiment of the present invention, that is, a laminated electrode body. In the figure, the symbol 3 represents the positive electrode formed by combining the positive electrode active material layer 32 and the positive electrode current collector 31, the symbol 5 represents the negative electrode formed by combining the negative electrode active material layer 52 and the negative electrode current collector 51, and the symbol 6 represents at least a part of plastic A binder of resin that is partially applied between the positive and negative electrodes, for example, in a dot-like, stripe-like, or grid-like pattern, to bond the positive and negative electrode active material layers 32 and 35 . A non-aqueous electrolyte solution containing lithium ions is contained in the gap 7 connecting the positive electrode active material layer 32 and the negative electrode active material layer 52, and the binder is used as an ion conducting layer. Plastic resins are solid at room temperature, have self-adhesive properties, and deform when heated or pressurized.

A lithium ion battery having the above structure can be formed, for example, by the following method.

The method for forming a battery of the present invention includes the following steps: partially applying an adhesive resin 6 between the positive electrode 3 and the negative electrode 5, and then deforming the adhesive resin 6 by heating or pressurizing as described below to reduce the amount of the positive electrode. 3 and the gap 7 between the negative electrode 5, and the depth L of the gap 7 is reduced to a certain predetermined value.

The adhesive resin 6 in the present invention is an adhesive resin that is insoluble in the electrolytic solution. The plastic resin in the adhesive resin 6 is not specifically limited, and polyolefin, polyglycol or silicone resin can be used. The adhesive resin 6 may further contain organic or inorganic powder, fiber, or the like.

The area of the void 7 due to the partial provision of the adhesive resin 6 should account for 30 to 90% of the interface area between the active material layers 32 and 35, preferably 60%. If the area is less than 30%, the electrical connection between the active material layers 32 and 35 is insufficient, increasing resistance to ion conduction and making it difficult to obtain sufficient battery characteristics. If the area is greater than 90%, the binder between the positive electrode 3 and the negative electrode 5 is insufficient, causing delamination.

The depth of the void 7 generated between the active material layers 32 and 35 , that is, the distance L between the active material layer 32 and the active material layer 35 varies depending on the ion conductivity of the electrolytic solution. L is 100 μm or less in the case of a commonly used electrolytic solution having an ion conductivity of 10 ⁻² S/cm. However, it is preferably ≥10 μm, because at this time, when an abnormal phenomenon such as a short circuit occurs and heat is generated, the melting of the plastic resin can play the role of cutting off the current.

In the method of partially disposing the adhesive resin 6 between the positive electrode 3 and the negative electrode 5, on one or both of the facing surfaces of the positive electrode 3 and the negative electrode, powdery, Resin in the shape of strips, grids, and interconnected pores. Specifically, available such as coater method, as shown in the perspective view of Fig. 2 (a) and the side view of Fig. 2 (b), extract the molten resin 6 with a rotating roller 21 having dot-shaped convex pits 21a thereon. , and then transfer. However, it is not limited to this method, and a spraying method or a coating method in which molten resin is injected from the pores of a rotating roll may also be used. By distributing the resin in an incompletely covered manner, a void 7 that can hold a liquid electrolyte is formed between the positive electrode 3 and the negative electrode 5 . By using the gap 7 to store the electrolyte, the resistance of ion conduction between the positive electrode 3 and the negative electrode 5 can be reduced to the same level as that of the case in the prior art. Furthermore, since the positive electrode 3 and the negative electrode 5 are bonded together with the adhesive resin 6, the positive electrode 3 and the negative electrode 5 can be closely bonded without a case.

After the adhesive resin 6 is partially applied between the positive electrode 3 and the negative electrode 5 to bond them, a step of applying pressure to deform the adhesive resin 6 may be performed at any time after the above-mentioned sandwiching and bonding. This step has the effect of increasing the contact area of the adhesive resin 6 with the positive electrode 3 and the negative electrode 5 and enhancing the binding force with the adhesive resin 6, so that the final battery can be very durable in practical use. Preferably, the bonding strength is determined by the anchoring effect caused by the penetration of the adhesive resin 6 into the micropores on the surfaces of the positive electrode 3 and the negative electrode 5 . However, even in the case where the bonding strength only depends on the self-adhesiveness of the adhesive resin 6, if the contact area between the adhesive resin 6 and the surfaces of the positive electrode 3 and the negative electrode 5 is sufficiently large, sufficient bonding when forming a battery can be ensured. strength. This step is also necessary to make the thickness of the adhesive resin 6 between the positive electrode 3 and the negative electrode 5 even and uniform. If the thickness of the adhesive resin 6 is too large, the charging capacity of the battery will decrease.

In the above-mentioned bonding method, since the plastic resin has self-adhesiveness, it has the following advantages, that is, it is not necessary to dry after bonding the positive electrode 3 and the negative electrode 5 each time; The steps of deforming the adhesive resin can be completed at one time; the use of solvent is reduced, thereby simplifying the equipment and greatly improving the productivity.

After pressure bonding, drying is performed, and the collector tabs 33 and 53 are joined to the obtained electrode body by spot welding or the like. The laminated electrode body was embedded in a cylinder made of aluminum laminated film 22 . An electrolytic solution was poured into the cylinder, and sealing was performed, thereby completing a lithium-ion battery having a single laminated electrode body (see FIG. 3 ).

Lithium-ion-containing non-aqueous electrolytic solutions used in existing batteries can be used as the liquid electrolyte (ion conductor) of the electrolytic solution in the present invention. Specifically, as a solvent for the liquid electrolyte, ester solvents such as ethylene carbonate, propylene carbonate, dimethyl carbonate, and diethyl carbonate can be used; dimethoxyethane, diethoxyethane, di Ether solvents such as diethyl ether and dimethyl ether; and mixtures of two or more substances selected from the above-mentioned substances of the same or different kind. As the electrolyte salt in the electrolyte, such as LiPF ₆ , LiAsF ₆ , LiClO ₄ , LiBF ₄ , LiCF ₃ SO ₃ , LiN(CF ₃ SO ₂ ) ₂ , LiC(CF ₃ SO ₂ ) ₃ , LiN(C ₂ F ₅ SO ₂ ) ₂ etc.

The active material layers 32 and 35 are formed by mixing the powdery positive and negative active material layers into a binder to form a slurry, which is applied to the positive and negative current collectors, respectively, and then dried.

The adhesive resin used to bond the active material to the electrode layer includes substances that are neither soluble in the electrolyte nor react inside the battery, such as polymers of vinylidene fluoride, vinyl fluoride, acrylonitrile, ethylene oxide, etc. or copolymers, and ethylene-propylene diamine rubber.

Active materials that can be used for the positive electrode 3 include: composite oxides of lithium and transition group metals such as cobalt, nickel or manganese; lithium-containing chalcogenides; or composite oxides of these compounds; Composite oxides, lithium-containing chalcogenides or composite oxides thereof. Graphite is added to these substances to serve as an electron conductor. Preferred active materials that can be used for the negative electrode 5 include carbon-containing compounds, such as graphite, graphitized carbon, non-graphitized carbon, polyacene, polyacetylene, and aromatic hydrocarbons with an acene structure, such as pyrene ( Or called pyrene), perylene. The negative electrode active material is not limited to these, and any material that can intercalate and remove lithium ions (which is necessary for battery operation) can be used. These active materials are used in granular form. Particles with a size of 0.3 to 20 [mu]m, preferably 0.3 to 5 [mu]m, can be used. Carbon fiber can also be used for the negative electrode active material layer 52 . If the particles are too small, the area of the active material covered by the binder will be too large during bonding, and lithium ions cannot be effectively intercalated and removed during charging, resulting in a decrease in battery performance. If the particles are too large, it is not easy to form a film, and the filling density also decreases.

Any metal that is stable inside the battery can be used as current collector 31 or 51 . The positive electrode 3 is preferably made of aluminum, and the negative electrode 5 is preferably made of copper. Current collectors 31 and 51 may be foil, mesh, expanded metal, or the like. Foil is preferred in view of the smoothness of the electrodes.

Although in the above method, bonding is achieved by plastically deforming the adhesive resin, it may also be achieved by using the adhesive resin 6 containing a thermoplastic resin and heating it at a temperature at which the thermoplastic resin is easily deformed or higher. accomplish. As a heating device, a hot plate, an oven or an infrared heater can be used.

Heating may be at a temperature at which the thermoplastic resin flows or higher. At this time, the contact area of the adhesive resin and the surfaces of the positive electrode 3 and the negative electrode 5 increases, and the resin penetrates into the micropores of these surfaces to produce an anchoring effect. If the adhesive resin is very viscous (which is advantageous in some cases, but need not be), pressure can be applied while heating.

Adhesive resin 6 adopts adhesive resin containing thermoplastic resin, which is not only easy to form the battery structure, but also has the effect of melting the resin to cut off the current when the temperature rises due to abnormal conditions such as short circuit.

Any thermoplastic resin can be used here as long as its melting point is ≤ 200°C and it is insoluble in the electrolyte. The thermoplastic resin may also contain high-melting-point components, inorganic substances, and the like as long as the fluidity when heated is not impaired.

When the adhesive resin 6 containing a thermoplastic resin is used, it is also possible to apply ultrasonic waves under pressure to achieve adhesion. Ultrasonic waves deform the resin effectively, making it easy to bond even at low pressure and low temperature. Also, application of ultrasonic waves can selectively heat the portion of the thermoplastic resin that is in contact with the electrodes, so that adhesion can be achieved very efficiently.

The heating step can be carried out at any time after all the electrodes are stacked one on top of the other. This step is effective for improving the heat resistance of the completed battery.

Although the embodiment of the present invention has been specifically described in connection with a battery having one laminated electrode body 8, the present invention is also applicable to a laminated type battery having a plurality of laminated electrode bodies. A small but stable battery with a large capacity can be obtained by using a plurality of laminated electrode bodies. For example, a laminated electrode body type battery can have the structure shown in Figure 4, wherein positive electrodes 3 and negative electrodes 5 are arranged alternately with sheet separators therebetween; or the structures of Figures 5 and 6, wherein positive electrodes 3 and negative electrodes 5 are rolled into A cylindrical shape with a strip-shaped separator sandwiched therebetween; or another structure not shown in which the positive electrode 3 and the negative electrode 5 are alternately embedded in the folded structure of the separator folded belt 4 . The laminated electrode body type battery shown in FIGS. 4-6 will be described in detail below in conjunction with embodiments.

The examples given below describe the invention in more detail, but the invention is not limited thereto. (Example 1)

87 wt % of LiCoO ₂ , 8 wt % of graphite powder, and 5 wt % of polyvinylidene fluoride as a binder were mixed to prepare a slurry of a positive electrode active material layer. The slurry was applied to a 20 [mu]m thick aluminum foil current collector with a medical blade to form a negative electrode at a coating thickness of about 100 [mu]m.

95 wt% of mesophase bead carbon (manufactured by Osaka Gas Co., Ltd.) and 5 wt% of polyvinylidene fluoride as a binder were mixed to prepare a negative electrode active material layer slurry. The slurry was applied to a 12 μm thick copper foil current collector with a medical blade to form a positive electrode at a coating thickness of about 100 μm.

The positive and negative electrodes were cut into rectangles of 5 cm x 4 cm, and terminals (sheets) for current collection were respectively fixed to the cut positive and negative electrodes.

SIS type hot-melt adhesive (AK-1, manufactured by Kanebo NSC Co., Ltd., softening point is about 100° C.) was sprayed at a coating amount of about 20 g/m ² , and partially applied to the positive and negative electrodes. Stack the positive and negative electrodes coated with adhesive, and apply a pressure of 5g/ ^cm2 to the adhesive layer to reduce the space between the positive and negative electrodes.

Then, the obtained electrode body was completely inserted into a cylinder made of an aluminum laminated film, sufficiently dried, and then injected with an electrolytic solution. The electrolyte uses ethylene carbonate or 1,2-dimethoxyethane as a solvent, and lithium hexafluorophosphate as an electrolyte. After injecting the electrolyte solution, the aluminum laminated film is sealed, and the production of the battery is completed.

As a performance of the battery thus produced, its gravimetric energy density was 80 Wh/kg at a current value of 1C. After charging 200 times at the current value C/2, the charging capacity can be guaranteed to be 90% of the original. (Example 2)

On the rectangular positive electrode and negative electrode of 5 cm × 4 cm, which were produced in the same manner as in Example 1, and on which the collector sheet was fixed, a butene-propylene copolymer was coated in a dot pattern with a coating machine (manufactured by MELTEX, CP3000). (manufactured by Nitta Gelatin Co., Ltd., softening point: 84° C.), and the application amount was about 18 g/m ² . Then, the positive and negative electrodes were stacked together, and a pressure of 20 g/cm ² was applied at 80° C. for one minute.

Then, the obtained electrode body was completely inserted into a cylinder made of an aluminum laminated film, sufficiently dried, and then injected with an electrolytic solution. The electrolyte uses ethylene carbonate or 1,2-dimethoxyethane as a solvent, and lithium hexafluorophosphate as an electrolyte. After injecting the electrolyte solution, the aluminum laminated film is sealed, and the production of the battery is completed.

As a performance of the battery thus produced, its gravimetric energy density was 75 Wh/kg at a current value of 1C. After charging 200 times at the current value C/2, the charging capacity can be guaranteed to be 80% of the original. (Example 3)

On the rectangular positive electrode and negative electrode of 5 cm × 4 cm, which were produced in the same manner as in Example 1, and on which the collector sheet was fixed, a butene-propylene copolymer was coated in a dot pattern with a coating machine (manufactured by MELTEX, CP3000). (manufactured by Nitta Gelatin Co., Ltd., softening point: 84° C.), and the application amount was about 15 g/m ² . Then, stack the positive and negative electrodes together, keep this shape, heat at 100°C for one minute, and then cool down.

Then, the obtained electrode body was completely inserted into a cylinder made of an aluminum laminated film, sufficiently dried, and then injected with an electrolytic solution. The electrolyte uses ethylene carbonate or 1,2-dimethoxyethane as a solvent, and lithium hexafluorophosphate as an electrolyte. After injecting the electrolyte solution, the aluminum laminated film is sealed, and the production of the battery is completed.

As a performance of the battery thus produced, its gravimetric energy density was 70 Wh/kg at a current value of 1C. After charging 200 times at the current value C/2, the charging capacity can be guaranteed to be 80% of the original. (Example 4)

On the rectangular positive electrode and negative electrode of 5 cm × 4 cm, which were produced in the same manner as in Example 1, and on which the collector sheet was fixed, ethylene-methyl methacrylate was coated in a dot pattern with a coating machine (manufactured by MELTEX Corporation, CP3000). An ester-maleic anhydride copolymer (manufactured by Sumitomo Chemical Co., Ltd., softening point: 100°C) was applied in an amount of about 18 g/m ² . Then, the positive and negative electrodes were stacked together, and a pressure of 20 g/cm ² was applied at 80° C. for one minute.

Then, the obtained electrode body was completely inserted into a cylinder made of an aluminum laminated film, sufficiently dried, and then injected with an electrolytic solution. The electrolyte uses ethylene carbonate or 1,2-dimethoxyethane as a solvent, and lithium hexafluorophosphate as an electrolyte. After injecting the electrolyte solution, the aluminum laminated film is sealed, and the production of the battery is completed.

As a performance of the battery thus produced, its gravimetric energy density was 78 Wh/kg at a current value of 1C. After charging 200 times at the current value C/2, the charging capacity can be guaranteed to be 80% of the original. (Example 5)

On the rectangular positive electrode and the negative electrode of 5cm * 4cm that are fixed on the current collector sheet made in the same manner as in Example 1, one deck of 30g/m ² polyethylene powder was evenly spread.

Then, the negative electrode is stacked on top of it, and combined with an ultrasonic welder, paying attention to reducing the ultrasonic output per unit area to avoid damaging the electrode.

Then, the obtained electrode body was completely inserted into a cylinder made of an aluminum laminated film, sufficiently dried, and then injected with an electrolytic solution. The electrolyte uses ethylene carbonate or 1,2-dimethoxyethane as a solvent, and lithium hexafluorophosphate as an electrolyte. After injecting the electrolyte solution, the aluminum laminated film is sealed, and the production of the battery is completed.

As a performance of the battery thus produced, its gravimetric energy density was 60 Wh/kg at a current value of 1C. After charging 200 times at the current value C/2, the charging capacity can be guaranteed to be 80% of the original. (Example 6)

This embodiment is a method of manufacturing a battery body having a flat laminated structure as shown in FIG. 4 .

In the same manner as in Example 1, a positive electrode and a negative electrode (or positive electrode) in a rectangular shape of 5 cm×4 cm were produced. Then, on both surfaces of the positive electrode, H6825 (trade name, manufactured by Nitta Gelatin Co., Ltd.) was applied as an adhesive resin in a dot pattern with a coater, and then the negative electrode and the positive electrode were stacked alternately, and a pressure of 100 g was applied. /cm ² , forming a uniform thin structure composed of a plurality of stacked electrode bodies.

Then, the obtained electrode body was completely inserted into a cylinder made of an aluminum laminated film, sufficiently dried, and then injected with an electrolytic solution. The electrolyte uses ethylene carbonate or 1,2-dimethoxyethane as a solvent, and lithium hexafluorophosphate as an electrolyte. After injecting the electrolyte solution, the aluminum laminated film is sealed, and the production of the battery is completed. (Example 7)

This embodiment is a manufacturing method of a battery body having a flat winding structure as shown in FIG. 5 .

A positive electrode of 5 cm x 23 cm and a negative electrode (or positive electrode) of 5 cm x 4 cm were produced in the same manner as in Example 1, and current collector tabs were respectively fixed to their ends by spot welding. Then, about 10 g/m ² of AK-1 (manufactured by Kanebo NSC Co., Ltd., softening point: about 100° C.) was coated on both surfaces of the positive electrode (or negative electrode). After that, one end of the negative electrode (or positive electrode) is folded back by a predetermined length, and at the same time, one positive electrode (or negative electrode) is inserted into the folded part. Glue the other positive electrode (or negative electrode) on the coated and folded portion facing the first inserted positive electrode (or negative electrode). The bonded positive electrode (or negative electrode) is wound into the positive electrode by winding. Another positive electrode (or negative electrode) is placed on the negative electrode (or positive electrode) in such a way as to face the first rolled positive electrode, and the negative electrode (or positive electrode) is wound up in the next winding. Repeat these steps to roll the electrode into an oval shape.

Then, the obtained electrode body was completely inserted into a cylinder made of an aluminum laminated film, sufficiently dried, and then injected with an electrolytic solution. The electrolyte uses ethylene carbonate or 1,2-dimethoxyethane as a solvent, and lithium hexafluorophosphate as an electrolyte. After injecting the electrolyte solution, the aluminum laminated film is sealed, and the production of the battery is completed. (Embodiment 8)

This embodiment is a manufacturing method of a battery body having a flat winding structure as shown in FIG. 6 .

In the same manner as in Example 1, a positive electrode and a negative electrode coated with an active material on a current collector sheet were produced, cut into 5 cm×23 cm, and a current collector sheet was fixed at one end thereof.

Spray SIS type hot-melt adhesive (AK-1, manufactured by Kanebo NSC Co., Ltd., softening point is about 100°C) with a coating amount of about 40g/ ^m2 on both sides of the positive electrode (or negative electrode) .

The positive electrode (or negative electrode) and the negative electrode (or positive electrode) are stacked together, folded every 5 cm and wound to form a roll structure. The resulting structure was pressed under a pressure of about 100 g/ ^cm2 to bond the electrodes, resulting in a uniform thin structure.

Then, the obtained electrode body was completely inserted into a cylinder made of an aluminum laminated film, sufficiently dried, and then injected with an electrolytic solution. The electrolyte uses ethylene carbonate or 1,2-dimethoxyethane as a solvent, and lithium hexafluorophosphate as an electrolyte. After injecting the electrolyte solution, the aluminum laminated film is sealed, and the production of the battery is completed.

As a performance of the battery thus produced, its gravimetric energy density was 70 Wh/kg at a current value of 1C. After charging 200 times at the current value C/2, the charging capacity can be guaranteed to be 80% of the original.

When the present invention manufactures high-performance secondary batteries for portable electronic devices such as portable computers and cordless phones, it can achieve miniaturization, light weight, arbitrary shape, simplification of manufacturing equipment, and thus improvement of productivity.

Claims (11)

1. the manufacture method of a lithium ion battery, this battery comprises the positive pole that is formed with positive electrode active material layer, the negative pole that is formed with negative electrode active material layer, and their are immersed in electrolyte, this method comprises the following steps:

Between positive pole and negative pole, partly stack the operation of the adhesive resin that comprises a part of plastic resin at least; And

Make the operation of above-mentioned adhesive resin distortion.

2. the manufacture method of lithium ion battery as claimed in claim 1 is characterized in that:

Make the adhesive resin distortion by applying the pressure or the bigger pressure that can make the plastic resin distortion.

3. the manufacture method of lithium ion battery as claimed in claim 1 is characterized in that:

Described plastic resin is a thermoplastic resin.

4. the manufacture method of lithium ion battery as claimed in claim 3 is characterized in that:

Make described adhesive resin distortion by heating.

5. the as claimed in claim 4 but manufacture method of ion battery is characterized in that:

The temperature of heating is more than the temperature that makes thermoplastic resin begin to flow.

6. the manufacture method of lithium ion battery as claimed in claim 3 is characterized in that:

Make described adhesive resin distortion by under the situation of pressurization, applying ultrasonic wave.

7. lithium ion battery, it is characterized in that having the laminate electrode body, this laminate electrode body comprises the positive pole with the positive electrode active material layer that links to each other with positive electrode collector, the negative pole with the negative electrode active material layer that links to each other with negative electrode collector and the adhesive resin that contains some moldable resin at least that disposes between described positive pole and described negative pole, form the space that is communicated with described positive pole and described negative pole therein by partly stacking this adhesive resin.

8. lithium ion battery as claimed in claim 7 is characterized in that:

Described plastic resin is a thermoplastic resin.

9. lithium ion battery as claimed in claim 7 is characterized in that:

The area in described space account for described positive pole and the opposed surface of described negative pole whole area 30～90%.

10. lithium ion battery as claimed in claim 7 is characterized in that: the distance between described positive pole and the described negative pole is below the 100 μ m.

11. lithium ion battery as claimed in claim 7 is characterized in that: have a plurality of laminate electrode bodies.

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