KR20070105724A - Anode plate and lithium rechargeable battery using the same and method of making anode plate - Google Patents

Abstract

A positive electrode plate is provided to ensure improved safety by generating carbon dioxide gas at an exact point upon overcharge to operate a safety vent. A positive electrode plate(112) includes a positive electrode current collector(113), a positive electrode active material layer(115) formed on one surface of the positive electrode current collector, and a mixture layer(116) of a conductive material and lithium carbonate(Li2CO3) formed on the other surface of the positive electrode current collector. A thickness ratio of the positive electrode active material layer and the mixture layer is 15:1 to 4:1. A weight ratio of lithium carbonate in the mixture layer is 25-55%.

Description

Anode plate and Lithium rechargeable battery using the same and Method of making anode plate

1 is a vertical cross-sectional view of a lithium secondary battery according to an embodiment of the present invention.

FIG. 2A is a perspective view of the bipolar plate of FIG. 1

FIG. 2B is a cross-sectional view taken along the line A-A of FIG. 2A

Figure 3 is a flow chart of the positive electrode plate manufacturing method according to the present invention

<Description of Symbols for Main Parts of Drawings>

100-lithium secondary battery 110-electrode assembly

112-anode plate 115-anode active material layer

116-Mixture Layer 140-Can

150-cap assembly

The present invention relates to a positive electrode plate and a method for manufacturing a lithium secondary battery and a positive electrode plate using the same, and more particularly, a positive electrode active material layer is formed on one side of the positive electrode plate and a mixture layer of lithium carbonate (Li ₂ CO ₃ ) and the conductive material on the other side By forming a, it is related to a positive electrode plate and a lithium secondary battery and a positive electrode plate manufacturing method using the same, which can improve the safety by allowing the safety van to operate by generating carbon dioxide at the exact time during overcharging.

With the recent rapid development of the electronics, telecommunications, and computer industries, the use of portable electronic products such as camcorders, mobile phones, notebook PCs, etc., as well as the compactness, light weight, and high functionality of the devices are becoming common. The demand for it is increasing. In particular, the rechargeable lithium secondary battery has a high energy density per unit weight and can be rapidly charged compared to conventional lead acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, etc. Development is underway.

When the lithium secondary battery is in a state such as overcharging or overcurrent, a danger of explosion and ignition is encountered, and thus a safety device capable of preventing overcharging is required. In general, a lithium secondary battery is manufactured by adding a gasification material such as biphenyl (BP) and cyclohexylbenzene (CHB) to an electrolyte, thereby generating a large amount of gas during overcharging to operate a safety band and a current blocking means. However, such a method is difficult to control the exact amount of gas generation, there is a problem that if added in excess, it will reduce the life of the battery and cause various side reactions.

On the other hand, lithium cobalt oxide (LiCoO ₂ ) is generally used as a positive electrode active material of a lithium secondary battery. The manufacturing method of lithium cobaltate is generally as follows.

Li ₂ Co ₃ (ℓ) + CoO ( s ) → LiCoO ₂ + CO ₂ ↑

That is, lithium carbonate (Li ₂ Co ₃ Lithium cobalt oxide by reacting a lithium compound such as lithium hydroxide (LiOH), lithium acetate (LiCOOH), and a cobalt compound such as cobalt oxide (CoO), cobalt carbonate (CoCO ₃ ), or cobalt hydroxide (Co (OH) ₂ ) Is manufactured. In this case, when lithium carbonate is used more than the stoichiometry of lithium cobalt so that Li / Co> 1 so that unreacted cobalt oxide does not remain, lithium carbonate is present in excess. The unreacted lithium carbonate generates carbon dioxide during overcharging to operate the safety band and the current blocking means. There is a method of preventing overcharging of the battery by this method. However, this method is inconvenient to separately control the weight ratio of lithium carbonate and lithium oxide when preparing the positive electrode active material in order to control the amount of gas generated. In addition, according to this method, there is a problem in that a separate positive electrode active material needs to be manufactured because the size of the void volume or the dead volume, which is an empty space, varies according to the specification of the battery. In addition, according to this method, there is a problem that it is difficult to manufacture a high-output battery because the timing of gas generation is not accurate to be used in a hybrid electric vehicle (HEV) requiring high safety.

The present invention has been made to solve the above problems, in particular, by forming a positive electrode active material layer on one side of the positive electrode plate and a mixture layer of lithium carbonate (Li ₂ CO ₃ ) and the conductive material on the other side, the exact time point during overcharge The purpose of the present invention is to provide a positive electrode plate and a method for manufacturing a lithium secondary battery and a positive electrode plate using the same, by which carbon dioxide is generated to allow a safety van to operate.

In order to solve the above problems, the positive electrode plate of the present invention includes a positive electrode current collector, a positive electrode active material layer formed on one side of the positive electrode current collector, and a conductive material and lithium carbonate formed on the other side of the positive electrode current collector. And a mixture layer of (Li ₂ CO 3).

In addition, the cathode active material layer may include a lithium compound selected from the group consisting of the following (1) to (13).

Li _x Mn _{1 - y} M _y A ₂ (1)

Li _x Mn _{1 - y} MyO _{2 - z} X _z (2)

Li _x Mn ₂ O _{4 - z} X _z (3)

Li _x Mn _{2 - y} M _y M ' _z A ₄ (4)

Li _x Co _{1 - y} M _y A ₂ (5)

Li _x Co _{1 - y} M _y O _{2 - z} X _z (6)

Li _x Ni _{1 - y} M _y A ₂ (7)

Li _x Ni _{1 - y} M _y O _{2 - z} X _z (8)

Li _x Ni _{1 - y} Co _y O _{2 - z} X _z (9)

Li _x Ni _{1 -y- z} Co _y M _z A _α (10)

Li _x Ni _{1 -y- z} Co _y M _z O _{2 -α} X _α (11)

Li _x Ni _{1 -y- z} Mn _y M _z A _α (12)

Li _x Ni _{1 -y- z} Mn _y M _z O _{2 -α} X _α (13)

(Wherein 0.9≤x≤1.1, 0≤y≤0.5, 0≤z≤0.5, 0≤α≤2, M and M 'are the same or different, Mg, Al, Co, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr, Mn, Cr, Fe, Sr, V and rare earth elements, A is selected from the group consisting of O, F, S and P And X is selected from the group consisting of F, S and P.)

In addition, the conductive material may be at least one selected from the group consisting of a graphite-based conductive material, a carbon black-based conductive material, a metal-based or metal compound-based conductive material. In this case, the graphite-based conductive material is at least one of artificial graphite and natural graphite, the carbon black-based conductive material is acetylene black, ketjen black, denka black, thermal black, channel black ( At least one of the channel black, the metal-based or metal compound-based conductive material is at least one of perovskite materials such as tin, tin oxide, tin phosphate (SnPO ₄ ), titanium oxide, potassium titanate, LaSrCoO ₃ , LaSrMnO ₃ It can be one.

In addition, the thickness ratio of the cathode active material layer and the mixture layer is preferably 15: 1 to 4: 1. In addition, the weight ratio of lithium carbonate in the mixture layer is preferably 25% to 55%.

In addition, the lithium secondary battery of the present invention includes a positive electrode current collector, a positive electrode active material layer formed on one side of the positive electrode current collector, a conductive material formed on the other side of the positive electrode current collector, and lithium carbonate (Li ₂ CO 3). An electrode assembly including a positive electrode plate having a mixture layer; A can containing the electrode assembly; And a cap assembly for sealing the top opening of the can.

In addition, the cathode active material layer may include a lithium compound selected from the group consisting of the following (1) to (13).

Li _x Mn _{1 - y} M _y A ₂ (1)

Li _x Mn _{1 - y} MyO _{2 - z} X _z (2)

Li _x Mn ₂ O _{4 - z} X _z (3)

Li _x Mn _{2 - y} M _y M ' _z A ₄ (4)

Li _x Co _{1 - y} M _y A ₂ (5)

Li _x Co _{1 - y} M _y O _{2 - z} X _z (6)

Li _x Ni _{1 - y} M _y A ₂ (7)

Li _x Ni _{1 - y} M _y O _{2 - z} X _z (8)

Li _x Ni _{1 - y} Co _y O _{2 - z} X _z (9)

Li _x Ni _{1 -y- z} Co _y M _z A _α (10)

Li _x Ni _{1 -y- z} Co _y M _z O _{2 -α} X _α (11)

Li _x Ni _{1 -y- z} Mn _y M _z A _α (12)

Li _x Ni _{1 -y- z} Mn _y M _z O _{2 -α} X _α (13)

(Wherein 0.9≤x≤1.1, 0≤y≤0.5, 0≤z≤0.5, 0≤α≤2, M and M 'are the same or different, Mg, Al, Co, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr, Mn, Cr, Fe, Sr, V and rare earth elements, A is selected from the group consisting of O, F, S and P And X is selected from the group consisting of F, S and P.)

In addition, the conductive material may be at least one selected from the group consisting of a graphite-based conductive material, a carbon black-based conductive material, a metal-based or metal compound-based conductive material. In this case, the graphite-based conductive material is at least one of artificial graphite and natural graphite, the carbon black-based conductive material is acetylene black, ketjen black, denka black, thermal black, channel black ( At least one of the channel black, the metal-based or metal compound-based conductive material is at least one of perovskite materials such as tin, tin oxide, tin phosphate (SnPO ₄ ), titanium oxide, potassium titanate, LaSrCoO ₃ , LaSrMnO ₃ It can be one.

In addition, the thickness ratio of the cathode active material layer and the mixture layer is preferably 15: 1 to 4: 1. In addition, the weight ratio of lithium carbonate in the mixture layer is preferably 25% to 55%. In addition, the lithium secondary battery may be used in a hybrid electric vehicle (HEV).

In addition, the positive electrode plate manufacturing method of the present invention comprises a positive electrode slurry manufacturing step for producing a positive electrode slurry containing a positive electrode active material; Mixture manufacturing step of producing a mixture containing a conductive material and lithium carbonate; A cathode active material layer coating step of coating the cathode slurry on one side of a cathode current collector; A mixture coating step of coating the mixture on the other side of the positive electrode current collector; It characterized in that it comprises a drying step of drying the positive electrode active material layer and the mixture.

In addition, the mixture preparation step is preferably made so that the weight ratio of the lithium carbonate is 25% to 55%. In addition, in the mixture manufacturing step, the lithium carbonate may be mixed in the form of a powder.

Hereinafter, the present invention will be described in more detail.

1 is a vertical cross-sectional view of a lithium secondary battery according to an embodiment of the present invention. 2A is a perspective view of the positive electrode plate of FIG. 1, and FIG. 2B is a sectional view taken along the line A-A of FIG. 2A. Hereinafter, the cylindrical lithium secondary battery has been described as an example, but the present invention can be applied to a square or pouch type lithium secondary battery.

The lithium secondary battery 100 according to an embodiment of the present invention, referring to FIG. 1, includes an electrode assembly 110, a can 140, and a cap assembly 150. The lithium secondary battery 100 is formed in a cylindrical shape.

The electrode assembly 110 is formed to include a positive electrode plate 112, a negative electrode plate 122, and a separator 120. In addition, the electrode assembly 110 may include a positive electrode tab 117 and a negative electrode tab 127.

2A and 2B, the positive electrode plate 112 includes a positive electrode current collector 113, a positive electrode active material layer 115, a mixture layer 116, and a positive electrode non-coating portion 118. In addition, the positive electrode plate 112 may further include a positive electrode tab 117.

The positive electrode current collector 113 is formed of a conductive metal material to collect electrons from the positive electrode active material layer 115 and move them to an external circuit. The cathode active material layer 115 is manufactured by mixing a cathode active material, a conductive material, and a binder, and is formed by coating a predetermined thickness on one side of the cathode current collector 113. As the cathode active material, lithium oxide having a structure capable of occluding / desorbing lithium ions is used. Lithium oxide used as a cathode active material is Li _x Mn _{1 - y} M _y A ₂ , Li _x Mn _{1 - y} MyO _{2 - z} X _z , Li _x Mn ₂ O _{4 - z} X _z , Li _x Mn _{2 - y} M _y M ' _z A ₄ , Li _x Co _{1- y} M _y A ₂ , Li _x Co _{1 - y} M _y O _{2 - z} X _z , Li _x Ni _{1 - y} M _y A ₂ , Li _x Ni _{1 - y} M _y O _{2 - z} X _z , Li _x Ni _{1 -y} Co _y O _2-z X _z , Li _x Ni _{1 -y- z} Co _y M _z A _α , Li _x Ni _{1 -yz} Co _y M _z O _2-α X _α , Li _x Ni _{1 -y- z} Mn _y M _z A _α , Li _x Ni _{1 -y- z} Mn _y M _z O _{2 -α} X _α (Where 0.9≤x≤1.1, 0≤y≤0.5, 0≤z≤0.5, 0≤α≤2, M and M 'are the same or different, Mg, Al, Co, K, Na, Is selected from the group consisting of Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr, Mn, Cr, Fe, Sr, V and rare earth elements, and A is composed of O, F, S and P It is selected from the group, X is selected from the group consisting of F, S and P.) Representatively, lithium cobaltate (LiCoO ₂ ) is used a lot. There may be a number of methods for producing lithium cobalt, but are generally prepared by the same method as in formula (1).

[Formula 1]

Li ₂ Co ₃ (ℓ) + CoO ( s ) → LiCoO ₂ + CO ₂ ↑

That is, lithium compounds such as lithium carbonate (Li ₂ Co ₃ ), lithium hydroxide (LiOH), lithium acetate (LiCOOH), cobalt oxide (CoO), cobalt carbonate (CoCO ₃ ), cobalt hydroxide (Co (OH) ₂ ) and Lithium cobalt acid is prepared by reacting the same cobalt compound. The production method of the positive electrode active material containing lithium cobalt is only one example, and the manufacturing method of the positive electrode active material is not limited thereto. 0.1-10 weight% is preferable with respect to an electrode active material, and, as for the addition amount of the said conductive material, it is more preferable that it is 1-5 weight%. When the content of the conductive material is less than 0.1% by weight, the electrochemical properties are lowered, and when the content of the conductive material is more than 10% by weight, the energy density per weight is lowered. However, the weight ratio of the conductive material is not limited thereto. That is, the cathode active material layer may be prepared by dispersing a cathode active material, a binder and a conductive material, if necessary, a thickener in a solvent to prepare a slurry composition, and applying the slurry composition to an electrode current collector. A thickener may be further added to the anode slurry. The thickener is not particularly limited as long as it can play a role of controlling the viscosity of the active material slurry. For example, carboxymethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and the like may be used. It is mixed with a solvent to prepare a binder solution. The binder is a material that serves to paste the active material, mutual adhesion of the active material, adhesion with the current collector, buffer effect on the expansion and contraction of the active material, and the like, for example, polyvinylidene fluoride, polyhexafluoropropylene- Copolymer of polyvinylidene fluoride (P (VdF / HFP)), poly (vinylacetate), polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone, alkylated polyethylene oxide, polyvinyl ether, poly (methylmeth) Acrylate), poly (ethylacrylate), polytetrafluoroethylene, polyvinylchloride, polyacrylonitrile, polyvinylpyridine, styrene-butadiene rubber, acrylonitrile-butadiene rubber and the like can be used. The content of the binder is preferably 1 to 10% by weight based on the electrode active material. When the content of the binder is less than 1% by weight, the content of the binder is too small, so that the adhesion between the electrode active material and the current collector is insufficient. When the content of the binder exceeds 10% by weight, the adhesion is improved, but the content of the electrode active material decreases by that amount, thereby increasing the battery capacity. It is disadvantageous to However, the weight ratio of the binder is not limited thereto. As the solvent, a nonaqueous solvent or an aqueous solvent is used. Non-aqueous solvents include N-methyl-2-pyrrolidone (NMP), dimethylformamide, dimethylacetamide, N, N-dimethylaminopropylamine, ethylene oxide, tetrahydrofuran and the like.

The mixture layer 116 is formed by coating a predetermined thickness on the other side of the positive electrode current collector 113. The mixture layer 116 is formed including a conductive material and lithium carbonate (Li ₂ CO ₃ ). The conductive material may be at least one selected from the group consisting of a graphite-based conductive material, a carbon black-based conductive material, a metal or a metal compound-based conductive material as a material for improving electronic conductivity. Examples of the graphite conductive material include artificial graphite and natural graphite, and examples of the carbon black conductive material include acetylene black, ketjen black, denka black, thermal black, and channel black ( channel black), and examples of the metal or metal compound conductive material include tin, tin oxide, tin phosphate (SnPO ₄ ), titanium oxide, potassium titanate, LaSrCoO ₃ , and perovskite material such as LaSrMnO _3. have. However, it is not limited to the conductive materials listed above. The conductive material contributes to improving the output by increasing the electrical conductivity of the mixture layer 116. In addition, the conductive material may improve the contact of lithium carbonate. The weight ratio of the lithium carbonate is preferably made to be 25% to 55% with respect to the entire mixture layer 116. If the weight ratio of the lithium carbonate is formed to be less than 25% is not generated enough gas, if the weight ratio of the lithium carbonate is formed to exceed 55% there is a problem that the coating thickness of the mixture is too thin and difficult to coat. In addition, it is preferable that the thickness ratio of the cathode active material layer 115 and the mixture layer 116 is 15: 1 to 4: 1. If the thickness ratio is formed to be less than 15: 1, the workability of the coating is very poor, if the thickness ratio is formed to exceed 4: 1 there is a problem that the energy density of the battery is significantly reduced. The mixture layer 116 may be used in a battery for a hybrid electric vehicle (HEV) to improve the output by a conductive material having excellent electrical conductivity. That is, the lithium secondary battery 100 is suitable for a hybrid electric vehicle requiring a high output. In addition, the mixture layer 116 may be used in a battery for a device that requires a high level of safety, including a hybrid electric vehicle, by lithium carbonate that generates carbon dioxide quickly during overcharging. The void volume or dead volume, which is an empty space inside the battery, varies depending on the battery specification. Therefore, the appropriate amount of carbon dioxide is also changed depending on the battery standard. The lithium secondary battery 110 may respond to various batteries having different specifications by a simple process by adjusting the lithium carbonate content of the mixture layer 116. That is, it is not necessary to adjust the composition ratio of the positive electrode active material layer according to the specification of the battery, so that the process becomes simple and simple.

The positive electrode non-coating portion 118 is a portion in which the positive electrode active material layer 115 or the mixture layer 116 is not formed in the positive electrode current collector 113. The positive electrode tab 117 is welded to one side of the positive electrode uncoated portion 118.

The negative electrode plate 122 includes a negative electrode current collector, a negative electrode active material layer, and a negative electrode non-coating portion. The negative electrode current collector is formed of a conductive metal material to collect electrons from the negative electrode active material layer and move them to an external circuit. The negative electrode active material layer is prepared by mixing a negative electrode active material, a conductive material and a binder, and is formed by coating a predetermined thickness on the negative electrode current collector. The negative electrode non-coating portion is a portion in which a negative electrode active material layer is not formed in the negative electrode current collector, and the negative electrode tab 127 is welded to one side of the negative electrode non-coating portion.

The positive electrode tab 117 and the negative electrode tab 127 are respectively welded to the positive electrode non-coating portion 118 and the negative electrode non-coating portion to serve to electrically connect the electrode assembly 110 and other parts of the battery. The positive electrode tab 117 and the negative electrode tab 127 are welded by resistance welding, and a lamination tape (not shown) may be attached to the welding portion to prevent short and heat generation. Here, the welding method of the positive electrode tab 117 and the negative electrode tab 127 is not limited.

The separator 120 may be interposed between the positive electrode plate 112 and the negative electrode plate 122 and may extend to surround the outer circumferential surface of the electrode assembly 110. The separator 120 is formed of a porous membrane polymer material to prevent short circuit between the positive electrode plate 112 and the negative electrode plate 122 and to allow lithium ions to pass therethrough.

The can 140 is formed in a cylindrical shape including a side plate 141 and a bottom plate 142. In addition, the side plate 141 has an outer circumferential surface and an inner circumferential surface that are substantially concentric with each other, and the bottom plate 142 has a front and a rear surface which are substantially parallel to each other. An upper end of the can 140 is opened to form an upper opening, and an electrode assembly 110 is inserted through the upper opening, and an electrolyte is injected. The upper portion of the can 140 prevents the electrode assembly 110 from flowing inside the can 140 after the electrode assembly 110 is inserted, and the beading portion 144 is provided to seat the cap assembly 150. After the insertion of the cap assembly 150, the creeping part 143 is formed to seal the battery. The can 140 is formed of a light and ductile aluminum or its alloy material, it is not limited to the material of the can 140. The can 140 is preferably manufactured by a deep drawing method, and the method of manufacturing the can 140 is not limited thereto.

The cap assembly 150 includes a safety vent 151, a current blocking means 152, a secondary protection element 153, and a cap up 154.

The safety vent 151 has a plate-shaped protrusion projecting downward in the center thereof and is positioned below the cap assembly 150, and the protrusion is deformed upward by the pressure generated inside the secondary battery. The positive electrode tab 117 of the positive electrode plate 112 and the negative electrode plate 122 of the electrode assembly 110, for example, the positive electrode plate 112, is welded to a lower surface of the safety vent 151 at a predetermined position. The safety vent 151 and the positive electrode plate 112 of the electrode assembly 110 are electrically connected. Here, in the other electrode plate of the positive electrode plate 112 and the negative electrode plate 122, for example, the negative electrode plate 122, the negative electrode tab 127 drawn from the negative electrode plate 122 is welded to the bottom surface of the bare cell, so that the can 140 and Electrically connected. The safety vent 151 deforms or ruptures when the pressure inside the can 140 rises due to carbon dioxide generated by the decomposition of the lithium carbonate in the mixture layer 116 during overcharging, thereby damaging the current blocking means 152. do. In addition, an upper portion of the safety van 151 is further provided with a current blocking means 152 that is broken when the safety van 151 is deformed and the current is cut off, and the upper portion of the current blocking means 152 when overcurrent The secondary protection element 153 is located to block the current. In addition, an upper portion of the secondary protection element 153 is further provided with a conductive cap up 154 that provides a positive voltage or a negative voltage to the outside.

Next, a method of manufacturing a positive electrode plate according to the present invention will be described.

3 shows a flowchart of a method of manufacturing a positive electrode plate according to the present invention.

Method for producing a positive electrode plate according to the present invention, referring to Figure 3, the positive electrode slurry manufacturing step (S10), mixture manufacturing step (S20), positive electrode active material layer coating step (S30), mixture coating step (S40) and drying step ( S50) is made.

The positive electrode slurry manufacturing step (S10) is a step of manufacturing a positive electrode slurry containing a positive electrode active material. The positive electrode slurry is prepared by dispersing a positive electrode active material, a binder and a conductive material, if necessary, a thickener in a solvent. Since the types of the positive electrode active material, the binder, the conductive material, and the thickener have been described above, detailed description thereof will be omitted.

The mixture preparation step (S20) is a step of preparing a mixture containing a conductive material and lithium carbonate. The mixture manufacturing step (S20) is preferably made so that the weight ratio of the lithium carbonate is 25% to 55%. In addition, the lithium carbonate in the mixture manufacturing step (S20) is preferably mixed in the form of a powder. The lithium carbonate is suitable for being rapidly dispersed in an overcharged state, evenly dispersed throughout the conductive material in a fine particle state.

The positive electrode active material layer coating step (S30) is a step of coating the positive electrode slurry on one side of the positive electrode current collector. The cathode active material layer coating step (S40) is generally made by using a coating apparatus including an unwinder, a coater head and a roller to unwind so as to coat the cathode current collector being wound. However, the configuration of the coating apparatus is not limited thereto.

The mixture coating step (S40) is a step of coating the mixture on the other side of the positive electrode current collector. The mixture coating step (S40) is made by a similar device to the coating apparatus used in the cathode active material layer coating step (S40).

The drying step (S50) is a step of drying the positive electrode active material layer and the mixture. The drying step (S50) is made using a drying device including a dryer and a winder. Since the drying apparatus may be combined with the coating apparatus, the cathode active material layer coating step (S30) and the mixture coating step (S40) may be made of a drying step (S50) and a series of processes. After the drying step (S50) is finished by using a cutter (sutter) to slitting the positive electrode plate according to the battery standard (sitting).

As described above, the present invention is not limited to the specific preferred embodiments described above, and any person having ordinary skill in the art to which the present invention pertains without departing from the gist of the present invention claimed in the claims. Various modifications are possible, of course, and such changes are within the scope of the claims.

According to the positive electrode plate and the lithium secondary battery according to the present invention, by forming a mixture layer containing lithium carbonate separately from the positive electrode active material layer to generate a carbon dioxide quickly and accurately during overcharging can be separated from the complex cathode active material manufacturing process to form a mixture layer This simplifies the process and has the effect of simplifying the process.

In addition, according to the present invention, since the amount of carbon dioxide generated can be precisely controlled by controlling only the amount of lithium carbonate to be added, there is an effect that there is no need to separately prepare a cathode active material according to the specification of the battery.

In addition, according to the present invention by forming a mixture layer containing a conductive material to improve the electrical conductivity to increase the output, as a result there is an effect that can be used in a hybrid electric vehicle.

Claims (16)

And a mixture layer of a positive electrode current collector, a positive electrode active material layer formed on one side of the positive electrode current collector, and a conductive material and lithium carbonate (Li ₂ CO 3) formed on the other side of the positive electrode current collector. Positive plate. The method of claim 1, The cathode active material layer is a cathode plate, characterized in that it comprises a lithium compound selected from the group consisting of (1) to (13). Li _x Mn _{1 - y} M _y A ₂ (1) Li _x Mn _{1 - y} MyO _{2 - z} X _z (2) Li _x Mn ₂ O _{4 - z} X _z (3) Li _x Mn _{2 - y} M _y M ' _z A ₄ (4) Li _x Co _{1 - y} M _y A ₂ (5) Li _x Co _{1 - y} M _y O _{2 - z} X _z (6) Li _x Ni _{1 - y} M _y A ₂ (7) Li _x Ni _{1 - y} M _y O _{2 - z} X _z (8) Li _x Ni _{1 - y} Co _y O _{2 - z} X _z (9) Li _x Ni _{1 -y- z} Co _y M _z A _α (10) Li _x Ni _{1 -y- z} Co _y M _z O _{2 -α} X _α (11) Li _x Ni _{1 -y- z} Mn _y M _z A _α (12) Li _x Ni _{1 -y- z} Mn _y M _z O _{2 -α} X _α (13) (Wherein 0.9≤x≤1.1, 0≤y≤0.5, 0≤z≤0.5, 0≤α≤2, M and M 'are the same or different, Mg, Al, Co, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr, Mn, Cr, Fe, Sr, V and rare earth elements, A is selected from the group consisting of O, F, S and P And X is selected from the group consisting of F, S and P.) The method of claim 1, The conductive material is a positive electrode plate, characterized in that at least one selected from the group consisting of graphite-based conductive material, carbon black-based conductive material, metal-based or metal compound-based conductive material. The method of claim 3, wherein The graphite-based conductive material is at least one of artificial graphite and natural graphite, the carbon black-based conductive material is acetylene black, ketjen black, denka black, thermal black, channel black At least one of the metal-based or metal compound-based conductive material is tin, tin oxide, tin phosphate (SnPO ₄ ), titanium oxide, potassium titanate, LaSrCoO ₃ , that is at least one of perovskite (perovskite) material such as LaSrMnO ₃ A positive electrode plate characterized by the above. The method of claim 1, The positive electrode plate, characterized in that the thickness ratio of the positive electrode active material layer and the mixture layer is 15: 1 to 4: 1. The method of claim 1, The positive electrode plate, characterized in that the weight ratio of lithium carbonate in the mixture layer is 25% to 55%. A positive electrode current collector, a positive electrode active material layer formed on one side of the positive electrode current collector, and a positive electrode plate including a mixture layer of a conductive material and lithium carbonate (Li ₂ CO 3) formed on the other side of the positive electrode current collector; Electrode assembly; A can containing the electrode assembly; And Lithium secondary battery comprising a cap assembly for sealing the top opening of the can. The method of claim 7, wherein The cathode active material layer is a lithium secondary battery comprising a lithium compound selected from the group consisting of (1) to (13). Li _x Mn _{1 - y} M _y A ₂ (1) Li _x Mn _{1 - y} MyO _{2 - z} X _z (2) Li _x Mn ₂ O _{4 - z} X _z (3) Li _x Mn _{2 - y} M _y M ' _z A ₄ (4) Li _x Co _{1 - y} M _y A ₂ (5) Li _x Co _{1 - y} M _y O _{2 - z} X _z (6) Li _x Ni _{1 - y} M _y A ₂ (7) Li _x Ni _{1 - y} M _y O _{2 - z} X _z (8) Li _x Ni _{1 - y} Co _y O _{2 - z} X _z (9) Li _x Ni _{1 -y- z} Co _y M _z A _α (10) Li _x Ni _{1 -y- z} Co _y M _z O _{2 -α} X _α (11) Li _x Ni _{1 -y- z} Mn _y M _z A _α (12) Li _x Ni _{1 -y- z} Mn _y M _z O _{2 -α} X _α (13) (Wherein 0.9≤x≤1.1, 0≤y≤0.5, 0≤z≤0.5, 0≤α≤2, M and M 'are the same or different, Mg, Al, Co, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr, Mn, Cr, Fe, Sr, V and rare earth elements, A is selected from the group consisting of O, F, S and P And X is selected from the group consisting of F, S and P.) The method of claim 7, wherein The conductive material is at least one selected from the group consisting of graphite-based conductive material, carbon black-based conductive material, metal-based or metal compound-based conductive material. The method of claim 9, The graphite-based conductive material is at least one of artificial graphite and natural graphite, the carbon black-based conductive material is acetylene black, ketjen black, denka black, thermal black, channel black At least one of the metal-based or metal compound-based conductive material is tin, tin oxide, tin phosphate (SnPO ₄ ), titanium oxide, potassium titanate, LaSrCoO ₃ , that is at least one of perovskite (perovskite) material such as LaSrMnO ₃ A lithium secondary battery characterized by the above. The method of claim 7, wherein The thickness ratio of the positive electrode active material layer and the mixture layer is a lithium secondary battery, characterized in that 15: 1 to 4: 1. The method of claim 7, wherein The lithium secondary battery, characterized in that the weight ratio of lithium carbonate in the mixture layer is 25% to 55%. The method of claim 7, wherein The lithium secondary battery is a lithium secondary battery, characterized in that used in hybrid electric vehicles (HEV). A cathode slurry manufacturing step of producing a cathode slurry containing a cathode active material; Mixture manufacturing step of producing a mixture containing a conductive material and lithium carbonate; A cathode active material layer coating step of coating the cathode slurry on one side of a cathode current collector; A mixture coating step of coating the mixture on the other side of the positive electrode current collector; A cathode plate manufacturing method comprising a drying step of drying the cathode active material layer and the mixture. The method of claim 14, Said mixture manufacturing step is a positive electrode plate manufacturing method characterized in that the weight ratio of the lithium carbonate is made from 25% to 55%. The method of claim 14, In the mixture manufacturing step, the lithium carbonate is a positive electrode plate manufacturing method, characterized in that mixed in the form of a powder.

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