JP2009032398A - Electrode body for battery and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode body for a battery capable of managing to improve both energy density and high rate characteristics. <P>SOLUTION: The electrode body for a battery includes a standard collector layer, an electrode layer formed on one of the surfaces of the standard collector layer and containing an active material, and an inner side collector layer arranged inside the electrode layer and capable of permeating a metal ion. The standard collector layer and the inner side collector layer are electrically jointed outside the electrode layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a battery electrode body capable of achieving both improvement in energy density and high-rate characteristics, a lithium ion battery using the battery electrode body, and a method for producing the battery electrode body.

  An electrode body used for a lithium ion battery or the like is usually a structure including a current collector made of a metal foil and an electrode layer (positive electrode layer or negative electrode layer) formed on the current collector and containing an active material. have. Conventionally, in order to increase the energy density of batteries, attempts have been made to increase the film thickness of the electrode layer and relatively reduce the proportion of current collectors and separators that do not contribute to energy density improvement. On the other hand, when the film thickness of the electrode layer is increased, there is a problem that the internal resistance increases and the high-rate characteristics deteriorate. Thus, energy density and high rate characteristics are in a trade-off relationship, and it has been difficult to achieve both.

  Conventionally, various studies on current collectors have been made. For example, Patent Document 1 discloses a current collector for a lithium ion battery in which a number of holes are punched in a metal foil. This is to improve the energy density by using a current collector having a through hole to prevent the active material from falling off and improving the cycle performance, and also to fill the inside of the through hole with the active material. However, since the amount of active material that can be filled in the through-hole is limited, a significant improvement in energy density cannot be expected. In addition, when the energy density is increased by increasing the thickness of the electrode layer, As in the prior art, there is a problem of causing an increase in internal resistance.

Patent Document 2 discloses a non-aqueous electrolyte secondary battery in which internal current is reduced and cycle performance is improved by using a current collector as a foam metal. Patent Documents 3 to 5 disclose a current collector having a through hole, a lithium secondary battery using the current collector, and the like.
JP-A-11-67222 Japanese Patent Laid-Open No. 9-213307 JP-A-11-86869 JP-A-11-97035 JP-A-2005-38612

  This invention is made | formed in view of the said situation, and it aims at providing the battery electrode body which can make energy density improvement and high-rate characteristic improvement compatible.

  In order to solve the above problems, in the present invention, a reference current collector layer, an electrode layer formed on one surface of the reference current collector layer, containing an active material, and disposed inside the electrode layer And an internal current collector layer that is permeable to metal ions, wherein the reference current collector layer and the internal current collector layer are electrically joined outside the electrode layer. A battery electrode body is provided.

  According to the present invention, by providing the internal current collector layer inside the electrode layer, it is possible to prevent the rate characteristics from being deteriorated even when the electrode layer is thick. Thereby, both energy density improvement and rate characteristic improvement can be achieved.

  In the above invention, it is preferable that two or more layers of the internal current collector layer are disposed in the electrode layer at a predetermined interval. This is because a battery electrode body with even better current collection efficiency can be obtained.

  In the said invention, it is preferable that the said electrode layer is formed on both surfaces of the said reference | standard collector layer. This is because it can be used for, for example, a wound battery.

  In the said invention, it is preferable that the said reference | standard collector layer is a collector layer which can permeate | transmit a metal ion. This is because a battery electrode body with excellent current collection efficiency can be obtained.

  In the present invention, a lithium ion having a positive electrode having a positive electrode layer and a positive electrode current collector, a negative electrode having a negative electrode layer and a negative electrode current collector, and a separator disposed between the positive electrode layer and the negative electrode layer A battery is provided, wherein at least one of the positive electrode and the negative electrode is the above-described battery electrode body.

  According to the present invention, by using the battery electrode body described above for at least one of the positive electrode and the negative electrode, a lithium ion battery excellent in both energy density and high rate characteristics can be obtained.

  In the present invention, a reference current collector layer that forms a reference current collector layer-electrode layer composite by applying an electrode layer forming paste containing an active material to the surface of the reference current collector layer- The electrode layer composite forming step and the internal current collector layer-electrode layer composite forming the internal current collector layer by applying the electrode layer forming paste to the surface of the internal current collector layer through which metal ions can pass. The current collector layer-electrode layer composite forming step, the reference current collector layer-electrode layer composite, and the internal current collector layer-electrode layer composite, the internal current collector layer is disposed inside the electrode layer. A method of manufacturing a battery electrode body comprising: a laminating step of stacking as described above; and a joining step of electrically joining the reference current collector layer and the internal current collector layer are provided.

  According to the present invention, a battery electrode body excellent in energy density and rate characteristics can be obtained.

  In the present invention, even if the film thickness of the electrode layer is increased, the high rate characteristic is not deteriorated, and an effect is achieved in which both energy density improvement and high rate characteristic improvement can be achieved.

  Hereinafter, the battery electrode body, lithium ion battery, and battery electrode body manufacturing method of the present invention will be described.

A. Battery Electrode Body First, the battery electrode body of the present invention will be described. The battery electrode body of the present invention includes a reference current collector layer, an electrode layer formed on one surface of the reference current collector layer, containing an active material, and disposed inside the electrode layer. A transmissive internal current collector layer, wherein the reference current collector layer and the internal current collector layer are electrically joined to each other outside the electrode layer.

  According to the present invention, by providing the internal current collector layer inside the electrode layer, it is possible to prevent the rate characteristics from being deteriorated even when the electrode layer is thick. Thereby, both energy density improvement and rate characteristic improvement can be achieved. As a result, for example, by using the battery electrode body of the present invention for a lithium secondary battery, a battery suitable for rapid charging and capable of increasing output can be obtained. Furthermore, in the present invention, current is collected at the reference current collector layer and the internal current collector layer, and each is externally joined. Therefore, compared to a method of collecting current from only the end face of the current collector, There is an advantage that current can be collected efficiently.

  FIG. 1 is a schematic cross-sectional view showing an example of a battery electrode body of the present invention. The battery electrode body shown in FIG. 1 is formed on one surface of a reference current collector layer 1, a reference current collector layer 1, an electrode layer 2 containing an active material, and disposed inside the electrode layer 2. The electrical current collector 4 having a through-hole through which metal ions can be transmitted, and the electrical current junction 4 that electrically joins the reference current collector layer 1 and the internal current collector layer 2 outside the electrode layer 2 And.

1. Material of Battery Electrode Body The material of the battery electrode body of the present invention will be described separately for a reference current collector layer, an electrode layer, and an internal current collector layer.

(1) Reference current collector layer The reference current collector layer used in the present invention carries an electrode layer described later on at least one surface. The material of the reference current collector layer is not particularly limited as long as it has conductivity, and the same material as that of a current collector used for a general lithium ion battery or the like may be used. it can. Specific examples include aluminum, copper, stainless steel, nickel, iron, and titanium. For example, when the battery electrode body of the present invention is used as a positive electrode of a lithium ion battery, the material of the reference current collector layer is preferably aluminum. On the other hand, when the battery electrode body of the present invention is used as the negative electrode of a lithium ion battery, the material of the reference current collector layer is preferably copper.

  The reference current collector layer may be a foil-like current collector layer or a current collector layer through which metal ions can pass. The current collector layer through which metal ions can be transmitted will be described in detail in “(3) Internal current collector layer” described later.

  The thickness of the reference current collector layer is not particularly limited as long as the desired electronic conductivity can be ensured, but is usually in the range of 5 μm to 20 μm, and particularly in the range of 10 μm to 15 μm. Preferably there is.

(2) Electrode layer Next, the electrode layer used for this invention is demonstrated. The electrode layer used in the present invention is a layer formed on at least one surface of the reference current collector layer and containing an active material. The type of active material used is appropriately selected according to the type of battery in which the battery electrode body of the present invention is used.

For example, when the battery electrode body of the present invention is used as a positive electrode of a lithium secondary battery, the electrode layer (positive electrode layer) usually contains a positive electrode active material, a conductive material, and a binder. The positive electrode active material is not particularly limited as long as it can occlude and release lithium ions. Examples thereof include LiCoO ₂ , LiCoO ₄ , LiMn ₂ O ₄ , LiNiO ₂ , and LiFePO _4. Among these, LiCoO ₂ is preferable. Examples of the conductive material include carbon black and acetylene black. Examples of the binder include polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE).

  In the present invention, an internal current collector layer described later is disposed inside the electrode layer. By disposing the internal current collector layer, the rate characteristics can be improved even when the electrode layer is thickened, and both the rate characteristics and the energy density can be improved. The total film thickness of the electrode layer is not particularly limited, but for example, it is preferably in the range of 50 μm to 200 μm, and more preferably in the range of 100 μm to 150 μm.

(3) Internal current collector layer Next, the internal current collector layer used in the present invention will be described. The internal current collector layer used in the present invention is a current collector layer disposed inside the electrode layer and capable of transmitting metal ions. In the present invention, “disposed inside the electrode layer” means that at least a part of the internal current collector layer exists inside the electrode layer. Therefore, for example, the internal current collector layer may be completely embedded in the electrode layer, or the surface of the internal current collector layer may be exposed from the electrode layer.

  The material of the internal current collector layer is not particularly limited as long as it has conductivity, and the same material as that of a current collector used for a general lithium ion battery or the like may be used. it can. The specific example is the same as the content described in the above “(1) Reference current collector layer”, and thus the description thereof is omitted here. In the present invention, the internal current collector layer and the reference current collector layer may be formed from the same material or may be formed from different materials.

  In the present invention, the internal current collector layer is a current collector layer capable of transmitting metal ions. In addition, metal ion here means the metal ion which moves between electrodes within a battery. Specifically, Li ion, Na ion, Al ion, Mg ion, Cs ion, etc. can be mentioned. Specific examples of the current collector layer that can transmit metal ions include those having a penetrating portion. Specifically, as shown in FIG. 2, the internal current collector layer having such a through portion has a circular through portion (FIG. 2 (a)), and has a slit-like through portion. And the like (FIG. 2B), those having a mesh-like through portion (FIG. 2C), and those having a comb-like through portion (FIG. 2D).

  The size of the penetrating portion is not particularly limited as long as metal ions can sufficiently permeate. For example, when the penetrating portion is circular, the diameter of the penetrating portion is preferably in the range of 100 μm to 1 mm, and more preferably in the range of 300 μm to 0.5 mm.

  The thickness of the internal current collector layer is not particularly limited as long as desired electronic conductivity can be ensured, but is usually in the range of 10 μm to 40 μm, and in particular in the range of 20 μm to 30 μm. Preferably there is.

2. Next, the configuration of the battery electrode body of the present invention will be described. The battery electrode body of the present invention has a reference current collector layer, an electrode layer formed on one surface of the reference current collector layer, and an internal current collector layer disposed inside the electrode layer. The reference current collector layer and the internal current collector layer are electrically connected to each other outside the electrode layer.

  Note that a method for performing electrical joining is not particularly limited, and a method of directly joining the reference current collector layer and the internal current collector layer may be used. The reference current collector layer and the internal current collector may be used. A method of joining the body layers with a joining lead or the like may be used. Specific examples of the joining method include a welding method.

  In the present invention, it is preferable that two or more layers of the internal current collector layer are disposed inside the electrode layer with a predetermined interval. This is because a battery electrode body with even better current collection efficiency can be obtained. Specifically, as shown in FIG. 3A, a battery electrode body having two internal current collectors 3 a and 3 b with a predetermined interval inside the electrode layer 2 can be exemplified. In FIG. 3A, the description of some reference numerals overlapping with those in FIG. 1 is omitted (the same applies to FIGS. 3B to 3D described later).

  In the battery electrode body as described above, the distance between the reference current collector layer and the internal current collector layer closest to the reference current collector layer is not particularly limited, and is, for example, 25 μm to 100 μm. It is preferable that it is in the range, especially in the range of 50 μm to 75 μm. The distance between adjacent internal current collector layers is preferably the same as the above range. Further, the number of the internal current collector layers arranged inside the electrode layer is at least one layer, preferably two layers or more, particularly preferably two layers or three layers.

  In the present invention, the electrode layer is preferably formed on both sides of the reference current collector layer. This is because it can be used for, for example, a wound battery. Specifically, as shown in FIG. 3 (b), the reference current collector layer 1 and an electrode layer 2a formed on one surface of the reference current collector layer 1 and having the internal current collector layer 3 disposed thereon. And an electrode layer 2 b formed on the other surface of the reference current collector layer 1.

  Furthermore, in the present invention, it is preferable that an internal current collector layer is disposed in each of the electrode layers formed on both surfaces of the reference current collector layer. This is because a battery electrode body with even better current collection efficiency can be obtained. Specifically, as shown in FIG. 3 (c), internal current collector layers 3a and 3b are arranged inside electrode layers 2a and 2b formed on both surfaces of the reference current collector layer 1, respectively. A battery electrode body can be mentioned. Two or more internal current collector layers may be disposed in the electrode layers 2a and 2b with a predetermined interval therebetween.

  In the present invention, the reference current collector layer may be a current collector layer capable of transmitting metal ions. Specifically, as shown in FIG. 3D, a reference current collector layer 1 that is a current collector layer through which metal ions can be transmitted, and one of the surfaces of the reference current collector layer 1 are formed. A battery electrode body having an electrode layer 2a on which the current collector layer 3 is disposed and an electrode layer 2b formed on the other surface of the reference current collector layer 1 can be exemplified.

  The shape of the battery electrode body of the present invention may be a flat plate type or a wound type. Furthermore, the battery electrode body of the present invention may be used for a battery that uses an electrolytic solution, or may be used for a battery that does not use an electrolytic solution. Specific examples of the battery using the electrolytic solution include an aqueous solvent battery and a nonaqueous solvent battery. Specific examples of the battery that does not use the electrolyte include an all-solid battery. Moreover, the battery electrode body of the present invention may be used for a primary battery or a secondary battery. In particular, the battery electrode body of the present invention is preferably used for lithium ion batteries (lithium primary batteries and lithium secondary batteries).

B. Next, the lithium ion battery of the present invention will be described. The lithium ion battery of the present invention includes a positive electrode having a positive electrode layer and a positive electrode current collector, a negative electrode having a negative electrode layer and a negative electrode current collector, and a separator disposed between the positive electrode layer and the negative electrode layer. In the lithium ion battery, at least one of the positive electrode and the negative electrode is the above-described battery electrode body.

  According to the present invention, by using the battery electrode body described above for at least one of the positive electrode and the negative electrode, a lithium ion battery excellent in both energy density and high rate characteristics can be obtained. Furthermore, since the battery electrode body is excellent in electronic conductivity, it has an advantage that a lithium secondary battery suitable for rapid charging and capable of high output can be obtained.

  FIG. 4 is a schematic cross-sectional view showing an example of the lithium ion battery of the present invention. The lithium ion battery shown in FIG. 4 includes a reference current collector layer 1, an electrode layer (negative electrode layer) 2 formed on one surface of the reference current collector layer 1 and containing a negative electrode active material, and an electrode layer 2. , An internal current collector layer 3 that is permeable to metal ions, and an electrical junction 4 that electrically joins the reference current collector layer 1 and the internal current collector layer 3 outside the electrode layer 2. More specifically, a battery electrode body 10, a positive electrode having a positive electrode layer 11 and a positive electrode current collector 12, an electrode layer 2, and a positive electrode layer 11 are used. And a separator 13 disposed between the two.

  The battery electrode body used in the present invention and other members constituting the lithium ion battery are the same as the contents described in the above-mentioned “A. Battery electrode body”, and thus the description thereof is omitted here. Further, since the electrolytic solution used is the same as that of a general lithium ion battery, description thereof is omitted here. In the present invention, at least one of the positive electrode and the negative electrode may be the above-described battery electrode body. Among them, both the positive electrode and the negative electrode are preferably the above-described battery electrode bodies.

  The lithium ion battery of the present invention may be a primary battery or a secondary battery. Furthermore, the shape of the lithium ion battery of the present invention is not particularly limited, and examples thereof include a cylindrical shape, a square shape, a laminate shape, and a coin shape.

C. Manufacturing method of battery electrode body Next, the manufacturing method of the battery electrode body of this invention is demonstrated. In the method for producing a battery electrode body according to the present invention, a reference current collector layer-electrode layer composite is formed by applying an electrode layer forming paste containing an active material to the surface of a reference current collector layer. By forming the reference current collector layer-electrode layer composite forming step and applying the electrode layer forming paste to the surface of the internal current collector layer through which metal ions can pass, the internal current collector layer-electrode layer composite An internal current collector layer-electrode layer composite forming step for forming a body, the reference current collector layer-electrode layer composite and the internal current collector layer-electrode layer composite, and the internal current collector layer It has a laminating process of stacking so as to be disposed inside the electrode layer, and a joining process of electrically joining the reference current collector layer and the internal current collector layer.

  According to the present invention, a battery electrode body excellent in energy density and rate characteristics can be obtained. Further, for example, a battery having excellent energy density and rate characteristics can be obtained by simultaneously laminating a plurality of internal current collector layer-electrode layer composites with respect to one reference current collector layer-electrode layer composite. The electrode body can be manufactured with an arbitrary film thickness.

FIG. 5 is a schematic cross-sectional view showing an example of the method for producing the battery electrode body of the present invention. In the method for manufacturing the battery electrode body shown in FIG. 5, the electrode layer 2 is formed on the surface of the reference current collector layer 1 by applying an electrode layer forming paste containing an active material. A reference current collector layer-electrode layer composite forming step (FIG. 5A) for forming the layer-electrode layer composite 21 and an electrode layer forming surface on the surface of the internal current collector 3 through which metal ions can pass. An electrode layer 2 is formed by applying a paste, and an internal current collector layer-electrode layer composite forming step (FIG. 5A) for forming an internal current collector layer-electrode layer composite 22 (FIG. 5A), a reference current collection A laminating step (FIG. 5 (c)) for stacking the electric current layer-electrode layer composite 21 and the internal current collector layer-electrode layer composite 22 so that the internal current collector layer 3 is disposed inside the electrode layer; After the laminating process, the reference current collector layer 1 and the internal current collector layer 3 are electrically joined to form an electrical joint 4 That the bonding step (FIG. 5 (d)), and has a.
Hereafter, the manufacturing method of the electrode layer for batteries of this invention is demonstrated for every process. In addition, since it is the same as that of the content described in said "A. battery electrode body" about each member used for this invention, description here is abbreviate | omitted.

1. Reference current collector layer-electrode layer composite formation step In the reference current collector layer-electrode layer composite formation step in the present invention, an electrode layer forming paste containing an active material is applied to the surface of the reference current collector layer. This is a step of forming a reference current collector layer-electrode layer composite.

  The electrode layer forming paste contains at least an active material, and may contain a conductive material, a binder, and the like as necessary. As the solvent used for the electrode layer forming paste, the same solvent as used for forming an electrode layer of a general lithium ion battery or the like can be used.

  In the present invention, the electrode layer forming paste is applied to at least one surface of the reference current collector layer. Depending on the configuration of the target battery electrode body, electrode layer forming paste may be applied to both surfaces of the reference current collector layer. The method for applying the electrode layer forming paste is not particularly limited as long as a desired electrode layer can be obtained. For example, a spray method, a dipping method, a dispensing method, a blade coating method, etc. Can be mentioned. In this invention, after apply | coating the paste for electrode layer formation, it is preferable to perform the drying process which dries an electrode layer, and the press process which improves an electrode density.

  In the reference current collector layer-electrode layer composite obtained by this step, the film thickness of the electrode layer formed on the reference current collector layer is not particularly limited, but is, for example, in the range of 25 μm to 100 μm. Especially, it is preferable that it exists in the range of 50 micrometers-75 micrometers.

2. Internal current collector layer-electrode layer composite formation step The internal current collector layer-electrode layer composite formation step in the present invention comprises the above electrode layer forming paste on the surface of the internal current collector layer through which metal ions can permeate. Is a step of forming an internal current collector layer-electrode layer composite.

  In the present invention, the electrode layer forming paste is applied to at least one surface of the internal current collector layer. If necessary, an electrode layer forming paste may be applied to both surfaces of the internal current collector layer. The method for applying the electrode layer forming paste, the drying process, and the pressing process are the same as those in the above-described reference current collector layer-electrode layer complex forming step, and thus the description thereof is omitted here.

  In the internal current collector layer-electrode layer composite obtained by this step, the thickness of the electrode layer formed on the reference current collector layer is not particularly limited, but for example within the range of 25 μm to 100 μm. Especially, it is preferable that it exists in the range of 50 micrometers-75 micrometers.

3. Laminating step The laminating step in the present invention is carried out by using the reference current collector layer-electrode layer composite and the internal current collector layer-electrode layer composite so that the internal current collector layer is disposed inside the electrode layer. It is a process of overlapping.

  In the present invention, the heating temperature for laminating the reference current collector layer-electrode layer composite and the internal current collector layer-electrode layer composite is not particularly limited, but is usually 100 ° C to 250 ° C. It is preferable that it is in the range of 150 to 200 degreeC. Furthermore, the pressure applied when laminating is not particularly limited, but is usually in the range of 0.1 MPa to 1 MPa, and preferably in the range of 0.3 MPa to 0.7 MPa. The laminating time is not particularly limited, and it is preferable that the lamination is performed until the composite is bonded to a degree having a desired adhesive strength.

  In the present invention, it is preferable to laminate a plurality of internal current collector layer-electrode layer composites simultaneously with respect to one reference current collector layer-electrode layer composite. This is because it is possible to obtain an electrode layer in which two or more internal current collector layers are arranged at a predetermined interval. Specifically, as shown in FIG. 6A, two internal current collector layer-electrode layer composites 22 are used for one reference current collector layer-electrode layer composite 21, and the internal current collector is used. Lamination is performed so that the electric conductor layer 3 is disposed inside the electrode layer 2. Thereby, as shown in FIG.6 (b), the electrode layer 2 by which the internal collector layer 3 was arrange | positioned two layers at predetermined intervals can be obtained.

4). Joining Step The joining step in the present invention is a step of electrically joining the reference current collector layer and the internal current collector layer. The joining step in the present invention is usually performed in the laminating step.

  The method of performing electrical joining is not particularly limited, and may be a method of directly joining the reference current collector layer and the internal current collector layer. The reference current collector layer and the internal current collector layer may be used. It is also possible to use a method of joining these with a joining lead or the like. Specific examples of the joining method include a welding method.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

Hereinafter, the present invention will be described in more detail with reference to examples.
[Example 1]
5 parts by weight of polyvinylidene fluoride (PVDF) as a binder was added to 5 parts by weight of the n-methylpyrrolidone solution, and propeller stirring was performed for 3 minutes. Next, 2 parts by weight of acetylene black as a conductive material was added, and propeller stirring was performed for 10 minutes. Next, 8 parts by weight of mesoporous silica was added, and propeller stirring was performed for 10 minutes. Next, 85 parts by weight of LiNiO ₂ powder as the positive electrode active material was added, and propeller stirring was performed for 10 minutes. Thus, a positive electrode layer forming paste was obtained.

Next, the positive electrode layer forming paste was applied onto a 15 μm thick Al current collector with a doctor blade and dried at 80 ° C. for 30 minutes. Next, it pressed with the roll press machine. Finally, punching was performed so as to have an electrode area of 3 cm ² to obtain a reference current collector layer-electrode layer composite (electrode A).

Next, the positive electrode layer forming paste was applied onto a 15 μm thick Al punching metal current collector with a doctor blade and dried at 80 ° C. for 30 minutes. Next, it pressed with the roll press machine. Finally, punching was performed so that the electrode area was 2 cm ² to obtain an internal current collector layer-electrode layer composite (electrode B).

Next, using the obtained electrode A, the electrode area was left at the center for 2 cm ² and the surrounding electrode layers were peeled off. The electrode A thus obtained and the above-mentioned electrode B were overlapped and laminated as shown in FIG. Finally, the reference current collector layer of the electrode A and the internal current collector layer of the electrode B were joined by ultrasonic welding to obtain the battery electrode body (positive electrode) of the present invention.

A measurement cell was obtained using the obtained positive electrode, Li metal prepared as the negative electrode, and a commercially available cell (manufactured by Nippon Tom Cell). The separator was a microporous film made of polyethylene (PE) having a thickness of 25 μm. In the electrolytic solution, lithium hexafluorophosphate (LiPF ₆ ) was dissolved as a supporting salt at a concentration of 1 mol / L in a mixed solvent in which ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed at a volume ratio of 3: 7. Things were used.

[Comparative Examples 1-3]
A measurement cell was obtained in the same manner as in Example 1, except that the composition and basis weight of the positive electrode layer forming paste were changed as shown in Table 1, and only the electrode A was used without using the electrode B. .

[Evaluation]
The energy density and capacity retention rate of the measurement cells obtained in Example 1 and Comparative Examples 1 to 3 were evaluated. First, the following SOC (state of charge) adjustment was performed, and then the energy density and capacity retention rate were measured.

(1) SOC adjustment Conditions for SOC adjustment are shown below.
(A) Charging: Current (15 mA for 1 g of active material), voltage 4.3 V, CC mode (b) Pause: 5 minutes (c) Discharge: Current (15 mA for 1 g of active material), voltage 3.0 V CC mode (d) Pause: 5 minutes These (a) to (d) were performed for 3 cycles. Then, in order to evaluate an energy density and a capacity | capacitance maintenance factor, charging / discharging (cycle 1 and cycle 2) was performed on the following conditions, respectively.

(2) Energy density Cycle 1
(E) Charging: Current (15 mA for 1 g of active material), voltage 4.3 V, CCCV mode, 24 hours (f) Pause: 2 hours (g) Discharge: Current (15 mA for 1 g of active material), voltage 3.0 V, CC mode (h) Pause: 5 minutes The amount of energy was calculated from the charge / discharge curve of this cycle 1, and the energy density (mWh / cc) was determined by the following formula.

(2) Capacity maintenance rate Cycle 2
(E) Charging: current (15 mA for 1 g of active material), voltage 4.3 V, CCCV mode, 24 hours (f) pause: 2 hours (g) Discharge: current (1500 mA for 1 g of active material), voltage 3.0 V, CC mode (h) Pause: 5 minutes Using the discharge capacity of cycle 2 and the discharge capacity of cycle 1 described above, the capacity retention rate (%) was determined by the following equation. The obtained results are shown in Table 1.

  Example 1 was excellent in both energy density and capacity retention rate (rate characteristics). Comparative Example 1 and Comparative Example 2 resulted in a low capacity retention rate. In Comparative Example 3, the energy density was small. From this, in Example 1, it became clear that an energy density can be improved and these can be made compatible, without reducing a capacity | capacitance maintenance factor.

It is a schematic sectional drawing which shows an example of the battery electrode body of this invention. It is explanatory drawing explaining the internal electrical power collector layer used for this invention. It is a schematic sectional drawing which shows the other example of the battery electrode body of this invention. It is a schematic sectional drawing which shows an example of the lithium ion battery of this invention. It is a schematic sectional drawing which shows an example of the manufacturing method of the battery electrode body of this invention. It is a schematic sectional drawing which shows the other example of the manufacturing method of the battery electrode body of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Reference | standard collector layer 2 ... Electrode layer 3 ... Internal collector layer 4 ... Electrical junction 10 ... Battery electrode body 11 ... Positive electrode layer 12 ... Positive electrode collector 13 ... Separator

Claims (6)

A reference current collector layer, an electrode layer formed on one surface of the reference current collector layer, containing an active material, an internal current collector layer disposed inside the electrode layer and capable of transmitting metal ions; Have
The battery electrode body, wherein the reference current collector layer and the internal current collector layer are electrically joined to each other outside the electrode layer.   2. The battery electrode body according to claim 1, wherein two or more layers of the internal current collector layer are disposed in the electrode layer at a predetermined interval.   The battery electrode body according to claim 1, wherein the electrode layer is formed on both surfaces of the reference current collector layer.   The battery electrode body according to any one of claims 1 to 3, wherein the reference current collector layer is a current collector layer through which metal ions can be transmitted. A positive electrode having a positive electrode layer and a positive electrode current collector, a negative electrode having a negative electrode layer and a negative electrode current collector, and a separator disposed between the positive electrode layer and the negative electrode layer,
5. The lithium ion battery according to claim 1, wherein at least one of the positive electrode and the negative electrode is the battery electrode body according to claim 1. Reference current collector layer-electrode layer composite forming step of forming a reference current collector layer-electrode layer composite by applying an electrode layer forming paste containing an active material to the surface of the reference current collector layer When,
Internal current collector layer-electrode layer composite that forms an internal current collector layer-electrode layer composite by applying the electrode layer forming paste to the surface of the internal current collector layer that is permeable to metal ions Forming process;
Laminating the reference current collector layer-electrode layer composite and the internal current collector layer-electrode layer composite so that the internal current collector layer is disposed inside the electrode layer; and
A bonding step of electrically bonding the reference current collector layer and the internal current collector layer;
The manufacturing method of the battery electrode body characterized by having.

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