JP5167577B2 - Non-aqueous electrolyte secondary battery - Google Patents

Description

  The present invention relates to a non-aqueous electrolyte secondary battery, and more particularly to a non-aqueous electrolyte secondary battery having a high power density per volume or weight.

A positive electrode plate in which a positive electrode active material mixture layer is formed on a positive electrode current collector and a negative electrode plate in which a negative electrode current collector is formed with a negative electrode active material mixture layer are alternately stacked via a separator and a container together with an electrolytic solution. A stacked type secondary battery enclosed in a battery is known (for example, see Patent Document 1). Non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries as one type of such secondary batteries are used in electric vehicles, hybrid vehicles, and the like as batteries capable of obtaining high output and high energy.
In an electric vehicle, in order to obtain a high voltage, a large number of batteries are usually connected in series, and a large current flows through each battery. Therefore, reducing the internal resistance of each battery is important for improving the output characteristics.

Various methods have been disclosed for improving the output characteristics of individual batteries. For example, the sum of the cross-sectional areas of the current collecting lead pieces directly derived from the positive electrode current collector is calculated as the positive electrode active material mixture layer. 0.006% to 0.048% with respect to the area of the coated surface, and the sum of the cross-sectional areas of the current collecting lead pieces directly derived from the negative electrode current collector is the amount of the coated surface of the negative electrode active material mixture layer It is disclosed that a non-aqueous electrolyte secondary battery having excellent assembly processability and excellent output characteristics can be realized by setting the content to 0.004% to 0.03% with respect to the area (for example, patents). Reference 2).
Japanese Patent Laid-Open No. 9-259859 JP 2002-270153 A

  However, for example, the conventional secondary battery as shown in Patent Document 2 is intended to reduce the internal resistance and improve the output characteristics, so that although the output characteristics are improved, the output with respect to the volume or weight is improved. That is, it is not configured to maximize the power density. In an electric vehicle or the like, there is a demand to install a large number of batteries to ensure sufficient output, but in order to effectively use a limited vehicle space and reduce power consumption when driving the vehicle, There is a desire to reduce the volume (volume) and weight as much as possible. Therefore, a battery mounted on an electric vehicle or the like not only has a large output, but also maximizes the output in relation to the volume (volume) and weight of the battery, that is, the battery volume, weight and output. It is very important to optimize the relationship, in other words to improve the power density.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a nonaqueous electrolyte secondary battery that maximizes (optimizes) the power density per volume or weight. is there.

In order to solve the above problems, a non-aqueous electrolyte secondary battery according to the present invention includes a positive electrode plate in which a positive electrode layer made of a positive electrode active material mixture is formed on a positive electrode current collector, and a negative electrode current collector. A non-aqueous electrolyte secondary battery having a negative electrode plate with a negative electrode layer formed of an agent, wherein the cross-sectional area of the positive electrode current collector is 0.003% or more and less than 0.006% of the formation area of the positive electrode layer It is characterized by being.
In the non-aqueous electrolyte secondary battery having such a configuration, the relationship between the electrode current collector and the cell volume is optimized with respect to the battery output, and the volume output density of the cell is improved.

Alternatively, the cross-sectional area of the positive electrode current collector is 0.004% or more and less than 0.006% of the formation area of the positive electrode layer.
In the non-aqueous electrolyte secondary battery having such a configuration, the relationship between the electrode current collector and the cell weight is optimized with respect to the battery output, and the weight output density of the cell is improved.

Further, another non-aqueous electrolyte secondary battery according to the present invention includes a positive electrode plate in which a positive electrode layer made of a positive electrode active material mixture is formed on a positive electrode current collector, and a negative electrode layer made of a negative electrode current collector made of a negative electrode active material mixture. A non-aqueous electrolyte secondary battery having a negative electrode plate formed with a positive electrode terminal (positive electrode tab) derived from the positive electrode current collector and a negative electrode terminal (negative electrode tab) derived from the negative electrode current collector The cross-sectional area of the positive electrode terminal is 0.003% or more and less than 0.006% of the formation area of the positive electrode layer.
Alternatively, the cross-sectional area of the positive electrode terminal is 0.004% or more and less than 0.006% of the formation area of the positive electrode layer.

  Further, another non-aqueous electrolyte secondary battery according to the present invention includes a positive electrode plate in which a positive electrode layer made of a positive electrode active material mixture is formed on a positive electrode current collector, and a negative electrode layer made of a negative electrode current collector made of a negative electrode active material mixture. A non-aqueous electrolyte secondary battery having a negative electrode plate, wherein a cross-sectional area of the negative electrode current collector is 0.002% or more and 0.004% or less of a formation area of the negative electrode layer. Features.

  Further, another non-aqueous electrolyte secondary battery according to the present invention includes a positive electrode plate in which a positive electrode layer made of a positive electrode active material mixture is formed on a positive electrode current collector, and a negative electrode layer made of a negative electrode current collector made of a negative electrode active material mixture. A non-aqueous electrolyte secondary battery having a negative electrode plate, wherein a cross-sectional area of the negative electrode terminal is 0.002% or more and 0.004% or less of a formation area of the negative electrode layer. To do.

  The present invention can provide a non-aqueous electrolyte secondary battery that maximizes (optimizes) the power density per volume or weight.

A thin battery according to an embodiment of the present invention will be described with reference to FIGS.
First, the overall configuration of the thin battery will be described with reference to FIGS. 1 and 2.
FIG. 1 is an overall perspective view of the thin battery 10, and FIG. 2 is a cross-sectional view of the thin battery 10 taken along line II in FIG. 1.
The thin battery 10 of the present embodiment is a lithium-based flat laminated type thin secondary battery. By using the thin battery 10 as a unit battery and stacking a desired number of the unit batteries, an assembled battery having a desired capacity is formed at a desired output voltage.

  As shown in FIG. 2, the thin battery 10 includes three positive plates 101, five separators 102, three negative plates 103, a positive electrode tab 104, a negative electrode tab 105, an upper exterior member 106, a lower exterior member 107, and It has an electrolyte (not shown). In the following description, a laminate of the positive electrode plate 101, the separator 102, and the negative electrode plate 103 is referred to as an electrode group, and the electrode group and the electrolyte are referred to as a power generation element 108.

The positive electrode plate 101 includes a positive electrode current collector 101a extending to the positive electrode tab 104, and positive electrode layers (positive electrode active material mixture) 101b and 101c formed on both main surfaces of a part of the positive electrode current collector 101a. And have.
In the thin battery 10 of the present embodiment, the cross-sectional area of the positive electrode current collector 101a of the positive electrode plate 101 is 0.004% or more of the formation area of the positive electrode layers 101b and 101c in order to maximize the electrode output density. The positive electrode side so that it is either in the range of less than 0.006% (when the weight output density is optimized) or in the range of 0.003% to less than 0.006% (when the volume output density is optimized). The shapes of the current collector 101a and the positive electrode layers 101b and 101c are defined. The fact that the electrode output density can be optimized by such an area ratio will be described later.

The positive electrode side current collector 101a of the positive electrode plate 101 is formed of an electrochemically stable metal foil such as an aluminum foil, an aluminum alloy foil, a copper foil, or a nickel foil. Further, the positive electrode layers 101b and 101c of the positive electrode plate 101 are made of, for example, lithium composite oxide such as lithium nickelate (LiNiO ₂ ), lithium manganate (LiMnO ₂ ), or lithium cobaltate (LiCoO ₂ ), chalcogen (S, Se). , Te) A mixture of a positive electrode active material such as a compound, a conductive agent such as carbon black, and an adhesive such as an aqueous dispersion of polytetrafluoroethylene. It is formed by applying to the main surface, drying and rolling.

The negative electrode plate 103 includes a negative electrode side current collector 103a extending to the negative electrode tab 105, and negative electrode layers 103b and 103c formed on both main surfaces of a part of the negative electrode side current collector 103a, respectively.
In the thin type battery 10 of this embodiment, in order to make the electrode power density maximum, the cross-sectional area of the negative electrode side current collector 103a of the negative electrode plate 103, 0.002% or more of the area for forming the negative electrode layer 103b and 103c 0 The shapes of the negative electrode side current collector 103a and the negative electrode plates 103b and 103c are defined so as to be in a range of less than 0.004%. The fact that the electrode output density can be optimized by such an area ratio will be described later.

The negative electrode side current collector 103a of the negative electrode plate 103 is formed of an electrochemically stable metal foil such as a nickel foil, a copper foil, a stainless steel foil, or an iron foil. Further, the negative electrode layers 103b and 103c of the negative electrode plate 103 are made of, for example, a negative electrode active material that absorbs and releases lithium ions of a positive electrode active material such as amorphous carbon, non-graphitizable carbon, graphitizable carbon, or graphite. An aqueous dispersion of a styrene butadiene rubber resin powder as a precursor material of an organic fired body is mixed, dried, pulverized, and carbonized surfaces carrying carbonized styrene butadiene rubber as a main material. The negative electrode plates 103b and 103c are formed by further mixing a binder such as an acrylic resin emulsion and applying the mixture to both main surfaces of a part of the negative electrode side current collector 103a, followed by drying and rolling. The
When amorphous carbon or non-graphitizable carbon is used as the negative electrode active material, there is no sudden decrease in output, so it is advantageous when used as a power source for electric vehicles.

The separator 102 of the power generation element 108 prevents a short circuit between the positive electrode plate 101 and the negative electrode plate 103 and may have a function of holding an electrolyte. The separator 102 is a microporous film made of polyolefin such as polyethylene (PE) or polypropylene (PP), for example. When an overcurrent flows, the pores of the layer are blocked by the heat generation, thereby blocking the current. It also has a function.
The separator 102 is not limited to a single-layer film such as polyolefin, but a film having a three-layer structure formed by sandwiching a polypropylene film with a polyethylene film or a film in which a polyolefin microporous film and an organic nonwoven fabric are laminated is used. You can also. Thus, by making the separator 102 into multiple layers, various functions such as an overcurrent prevention function, an electrolyte holding function, and a separator shape maintenance (stiffness improvement) function can be provided.

  As shown in FIG. 2, the above power generation element 108 has positive plates 101 and negative plates 103 alternately stacked with separators 102 interposed therebetween. The three positive electrode plates 101 are connected to the positive electrode tabs 104 made of metal foil through the margins of the positive electrode current collector 101a where the positive electrode layers 101b and 101c are not formed. Similarly, the three negative plates 103 are respectively connected to the negative tabs 105 made of metal foil through the margins of the negative current collector 103a where the negative plates 103b and 103c are not formed.

  The positive electrode tab 104 and the negative electrode tab 105 each have a cross-sectional area of the positive electrode plate 101 or the negative electrode plate 103 connected to the positive electrode side current collector 101a and the negative electrode side current collector, in order to ensure the output density of the thin battery 10. The shape is defined to be equal to the sum of the cross-sectional areas of the electric body 103a. That is, the positive electrode tab 104 has a cross-sectional area equal to the sum of the cross-sectional areas of the positive electrode-side current collectors 101 a of the three positive electrode plates 101, and the negative electrode tab 105 has the negative electrode side of the three negative electrode plates 103. Each is formed in a cross-sectional area equal to the sum of the cross-sectional areas of the current collector 103a.

  As described above, the cross-sectional area of each positive electrode side current collector 101a is 0.003% or more and less than 0.006%, or 0.004% or more and less than 0.006% of the total area of the positive electrode layers 101b and 101c. Therefore, the cross-sectional area of the positive electrode tab 104 is 0.003% to less than 0.006% of the total area of the positive electrode layers 101b and 101c of the three positive electrode plates 101, or 0.004% to 0. The area is less than 0.006%. Similarly, since the cross-sectional area of each negative electrode side current collector 103a is defined to be 0.002% or more and less than 0.004% of the total area of the negative electrode layers 103b and 103c, the cross-sectional area of the negative electrode tab 105 is The area is 0.002% or more and less than 0.004% of the total area of the negative electrode layers 103b and 103c of the three negative electrode plates 103.

  If the cross-sectional areas of the positive electrode tab 104 and the negative electrode tab 105 are made smaller than the sum of the cross-sectional areas of the positive electrode side current collector 101a or the negative electrode side current collector 103a, the internal resistance of the tab becomes larger than the resistance of the current collector. The internal resistance increases and the output density decreases. Further, when the cross-sectional areas of the positive electrode tab 104 and the negative electrode tab 105 are made larger than the sum of the cross-sectional areas of the positive electrode side current collector 101a or the negative electrode side current collector 103a, the weight of the tab becomes larger than necessary. Therefore, as described above, the cross-sectional areas of the positive electrode tab 104 and the negative electrode tab 105 are preferably equal to the sum of the cross-sectional areas of the positive electrode side current collector 101a and the negative electrode side current collector 103a, respectively.

  The positive electrode tab 104 and the negative electrode tab 105 are not particularly limited as long as they are electrochemically stable metal materials, but as the positive electrode tab 104, for example, an aluminum foil, an aluminum alloy foil, A copper foil, nickel foil, etc. can be mentioned. Moreover, as the negative electrode tab 105, nickel foil, copper foil, stainless steel foil, iron foil, etc. can be mentioned similarly to the above-mentioned negative electrode side collector 103a, for example.

  The number of the positive electrode plate 101, the separator 102, and the negative electrode plate 103 of the power generation element 108 is not limited to the above number. For example, the power generation element 108 can also be configured with one positive plate 101, three separators 102, and one negative plate 103, and the number of positive plates, separators, and negative plates can be selected as necessary. can do.

  In the present embodiment, the metal foil itself constituting the current collectors 101 a and 103 a of the electrode plates 101 and 103 is extended to the electrode tabs 104 and 105, so that the electrode plates 101 and 103 are directly attached to the electrode tabs 104 and 105. Although connected, the current collectors 101a and 103a of the electrode plates 101 and 103 and the electrode tabs 104 and 105 are connected by materials and parts different from the metal foils constituting the current collectors 101a and 103a. Also good.

The power generation elements 108 of these thin batteries 10 are sealed in a state where they are covered with an upper exterior member 106 and a lower exterior member 107 (exterior member). In other words, the power generation element 108 is enclosed in the internal space 111 of the thin battery 10 formed by the upper exterior member 106 and the lower exterior member 107.
The upper exterior member 106 and the lower exterior member 107 in this embodiment are a metal foil, an inner resin sheet formed of a resin excellent in electrolytic solution resistance, and a surface resin sheet formed of a resin excellent in electrical insulation. And a laminate film having a three-layer structure. Specifically, for example, an aluminum foil is preferable as the internal metal foil, and a polyamide-based resin such as nylon or a polyester-based resin is preferable as the surface resin sheet as the outer layer. Further, as the inner resin sheet, for example, polyethylene, modified polyethylene, polypropylene, modified polypropylene, or ionomer is suitable. Since these resins are excellent in heat weldability, they are more suitable in the case of a structure in which the upper exterior member 106 and the lower exterior member 107 are thermally welded.
The thin battery 10 has such a configuration.

In the thin battery 10 having such a configuration, in order to optimize the electrode output density (electrode weight output density, electrode volume output density), as described above, the positive electrode side current collector 101a has the cross-sectional area of the positive electrode. The layers 101b and 101c are formed so as to be in a range of 0.003% to less than 0.006%, or in a range of 0.004% to less than 0.006%. Further, the negative electrode side current collector 103a is formed so that its cross-sectional area is in the range of 0.002% or more and less than 0.004% of the formation area of the negative electrode layers 103b and 103c.
The optimization of the electrode output density with such a configuration will be described with reference to FIGS.

Generally, the configuration of the positive electrode plate 101 and the negative electrode plate 103 used in the thin battery 10 can be considered as a configuration like the electrode plate 201 shown in FIG. FIG. 3A is a plan view of the electrode plate 201, and FIG. 3B is a side view of the electrode plate 201.
An electrode plate 201 shown in FIG. 3 includes a current collector 203a formed of a metal foil, and electrode layers 203b and 203c formed by applying an electrode material on both main surfaces thereof. On one side of the current collector 203a, there is formed a current collector blank portion 211 where the electrode layers 203b and 203c are not formed and the current collector 203a is exposed, and an electrode tab 204 is connected to the current collector blank portion 211. Is done.

  In the electrode plate 201 having such a configuration, the electrode weight output density or the electrode volume output density (output density per weight or per volume) is the total of the electrode plate 201 as shown in the equations (1) and (2). It can be considered that the reciprocal of the resistance R is divided by the total electrode plate weight Tw or the total electrode plate volume Tv. The total resistance R of the electrode plate 201 is obtained by adding the internal resistance Ra of the electrode layers 203b and 203c to the internal resistance Rc of the current collector 203a, as shown in Expression (3).

(Equation 1)
Electrode weight output density = (1 / R) / Tw (1)
(Equation 2)
Electrode volume output density = (1 / R) / Tv (2)
(Equation 3)
R = Rc + Ra (3)

For example, in the electrode plate 201 shown in FIG. 3, the electrode width (width of the electrode plate 201) W is 120 mm, the length of the electrode layer forming part (electrode application part) (length of the electrode layers 203b and 203c) La is 200 mm, The length Lb of the electrode non-formation portion (total blank portion) including the current collector blank portion 211 and the electrode tab 204 is 20 mm, the electrode thickness (thickness of the electrode plate 201) H is 60 μm, and the thickness Hc of the current collector 203a is 20 μm.
And considering the case where the electrode plate 201 is a positive electrode plate, the weight of the electrode layers (positive electrode layers) 203b and 203c is 3 g, the resistance (Ra) of the electrode layers (positive electrode layers) 203b and 203c is 20 mΩ, An aluminum foil (Al foil) is used as the current collector 203a. The Al foil has a specific resistance of 0.025 mΩ · mm and a density of 0.0027 g / mm ³ .

  In this case, the internal resistance Rc of the current collector 203a is obtained by the following equation (4), and the total weight Tw and the total volume Tv of the electrode plate 201 are obtained by the following equations (5) and (6), respectively.

(Equation 4)
Rc = specific resistance / cross-sectional area × length / 2 (4)
= 0.025 / 120 / (20/1000) x (200 + 20) / 2
= 1.146
(Equation 5)
Tw = current collector density × current collector volume + electrode layer weight (5)
= 0.0027 × 120 × (20/1000) × (200 + 20) +3
= 4.426
(Equation 6)
Tv = electrode width × total electrode thickness × total electrode length (6)
= 120 × (60/1000) × (200 + 20)
= 1584

Accordingly, when Expression (3) to Expression (6) are substituted into Expression (1) and Expression (2), the electrode plate (positive electrode plate) 201 in this case is expressed as Expression (7) and Expression (8), respectively. Electrode weight output density and electrode volume density are determined.
(Equation 7)
Electrode weight output density = (1 / (1.146 + 20)) / 4.426
= 0.0106
(Equation 8)
Electrode volume output density = (1 / (1.146 + 20)) / 1588
= 0.00003

  The electrode weight output density or the electrode volume output density is detected for each condition and each component in which various parameters related to the configuration of the electrode plate 201 are changed, and each condition and the current collector 203a in each configuration are detected. The ratio of the cross-sectional area to the formation area (coating area) of the electrode layers 203b and 203c is detected. Then, by detecting the ratio between the cross-sectional area of the current collector 203a at which the electrode output density is sufficiently high and the coating area of the electrode layers 203b and 203c, the optimal cross-sectional area of the current collector 203a and the electrode layer 203b and The relationship with the coating area 203c is detected.

For the positive electrode plate, the thickness Hc of the Al foil as the current collector 203a is in the range of 10 μm to 30 μm, and the length Lb of the electrode non-formation part (total blank part) including the current collector blank part 211 and the electrode tab 204 is in the range of 10 mm to 50 mm, the electrode layer 203b and 203c coating amount in the range of ^{10mg / cm 2 ~40mg / cm 2} , the entire electrode plate 201 including the thickness of the current collector 203a and the thickness H of 50μm~150μm The electrode plate (positive electrode plate) 201 is configured by changing the specific resistance of the electrode layers 203b and 203c within a range of 10Ω to 50Ω. The specific resistance of the Al foil is 0.025 mΩ · mm, and the density of the Al foil is 0.0027 g / mm ³ .

  Under each condition, the electrode output density is obtained by the above-described equation, and the ratio between the cross-sectional area of the current collector 203a and the coating area of the electrode layers 203b and 203c in the configuration is detected. At this time, by selecting parameters sequentially so that only the cross-sectional area of the current collector 203a and the coating area of the electrode layers 203b and 203c change with respect to a certain condition and other conditions do not change as much as possible. It is possible to directly detect the influence of the electrode output density on the ratio of the cross-sectional area of the electric body and the coating area of the electrode layer.

FIG. 4 shows the relationship between the electrode weight output density and the ratio between the cross-sectional area of the current collector thus obtained and the coating area of the electrode layer.
In FIG. 4, a series of two types of consecutively arranged dots A ₁ and B ₁ are respectively applied to the cross-sectional area of the current collector 203a and the coating of the electrode layers 203b and 203c under specific conditions. The value of the electrode weight output density detected when the ratio with the area is changed is shown. Two series of dots A ₁ and B ₁ are the ratio of the cross-sectional area of the current collector to the coating area of the electrode layer in the peak value of the electrode weight output density in the series of electrode weight output density values. It is a column which shows the case where is the largest and the smallest. The dots other than the series of dots A ₁ and B ₁ are a series of electrode weight output densities when the ratio between the cross-sectional area of the current collector and the coating area of the electrode layer is changed under various conditions. It shows the peak value among the values.

  As is apparent from FIG. 4, the ratio of the cross-sectional area of the current collector that gives the highest electrode weight output density to the coating area of the electrode layer is concentrated between 0.004% and 0.006%. . Therefore, even if other parameters change to some extent, the ratio between the cross-sectional area of the current collector and the coating area of the electrode layer is between 0.004% and 0.006%. Thus, with respect to the positive electrode plate, an electrode plate (positive electrode plate) having the highest electrode weight output density or nearly the highest electrode density can be configured.

FIG. 5 shows the relationship of the electrode volume output density with respect to the ratio between the cross-sectional area of the current collector and the coating area of the electrode layer obtained by similarly changing the parameters for the positive electrode plate.
Also in FIG. 5, two types of dot arrays A ₂ and B ₂ arranged continuously are respectively the cross-sectional area of the current collector 203a and the coating area of the electrode layers 203b and 203c under specific conditions. And the ratio of the cross-sectional area of the current collector and the coating area of the electrode layer at the peak value of the electrode volume output density is the largest. This is a column indicating the smallest case. Further, dots other than these continuous dot rows A ₂ and B ₂ are peaks in the value of the electrode volume output density with respect to the ratio between the cross-sectional area of the current collector and the coating area of the electrode layer under various conditions. Value.

  As is apparent from FIG. 5, the ratio between the cross-sectional area of the current collector and the coating area of the electrode layer, at which the electrode volumetric power density is highest under various conditions, is between 0.003% and 0.006%. Concentrate on. From this, even if other parameters change to some extent, the ratio between the cross-sectional area of the current collector and the coating area of the electrode layer is in the range of 0.003% to 0.006%. As for the positive electrode plate, an electrode plate (positive electrode plate) having the highest or almost the highest electrode volume output density can be configured.

For the negative electrode plate, by using a Cu foil as the current collector 203a and using a desired negative electrode material as the electrode layers 203b and 203c, the electrode gravity output density and the electrode volume output are the same as in the case of the positive electrode plate described above. Can detect density.
For the negative electrode plate, the Cu foil thickness Hc is in the range of 10 μm to 15 μm, and the length Lb of the electrode non-formation portion (total blank portion) including the current collector blank portion 211 and the electrode tab 204 is in the range of 10 mm to 50 mm. , the range of coverage of the electrode layer 203b and 203c of ^{5mg / cm 2 ~30mg / cm 2} , the thickness H of the entire electrode plate 201 including the thickness of the current collector 203a in the range of 60Myuemu～180myuemu, also, the electrode The electrode plate (negative electrode plate) 201 is configured by changing the specific resistance of the layers 203b and 203c between 2Ω and 20Ω.
Under each condition, the electrode output density is obtained by the above-described equation, and the ratio between the cross-sectional area of the current collector 203a and the coating area of the electrode layers 203b and 203c in the configuration is detected.

FIG. 6 shows the relationship between the electrode weight output density and the ratio between the cross-sectional area of the current collector thus obtained and the coating area of the electrode layer.
In FIG. 6, a series of two types of dot arrays A ₃ and B ₃ arranged in succession are respectively applied to the cross-sectional area of the current collector 203a and the coating of the electrode layers 203b and 203c under specific conditions. The value of the electrode weight output density detected when the ratio with the area is changed is shown. Two series of dots A ₃ and B ₃ are the ratio of the cross-sectional area of the current collector to the coating area of the electrode layer in the peak value of electrode weight output density in the series of electrode weight output density values. It is a column which shows the case where is the largest and the smallest. Further, these dots other than the series of dots A ₃ and B ₃ are a series of electrode weight output densities when the ratio between the cross-sectional area of the current collector and the coating area of the electrode layer is changed under various conditions. It shows the peak value among the values.

  As is apparent from FIG. 6, the ratio of the cross-sectional area of the current collector and the coated area of the electrode layer where the electrode weight output density is maximum under various conditions is between 0.002% and 0.004%. Concentrate on. Therefore, even if other parameters change to some extent, the ratio between the cross-sectional area of the current collector and the coating area of the electrode layer is between 0.002% and 0.004%. Thus, with respect to the negative electrode plate, an electrode plate (negative electrode plate) having the highest electrode weight output density or almost the highest value can be configured.

FIG. 7 shows the relationship of the electrode volume output density with respect to the ratio between the cross-sectional area of the current collector obtained by similarly changing the parameters and the coating area of the electrode layer for the negative electrode plate.
In FIG. 7, a series of two series of dots A ₄ and B ₄ arranged in succession are respectively applied to the cross-sectional area of the current collector 203a and the coating of the electrode layers 203b and 203c under specific conditions. The value of the electrode volume output density when the ratio with the area is changed is shown. Two series of dots A ₄ and B ₄ are the ratio of the cross-sectional area of the current collector to the coating area of the electrode layer in the peak value of the electrode volume output density in the series of electrode volume output density values. It is a column which shows the case where is the largest and the smallest. Further, dots other than these continuous dot rows A ₄ and B ₄ are peaks in the value of the electrode volume output density with respect to the ratio between the cross-sectional area of the current collector and the coating area of the electrode layer under various conditions. Value.

  As is apparent from FIG. 7, the ratio of the cross-sectional area of the current collector and the coated area of the electrode layer, at which the electrode volumetric power density is the highest, under various conditions is between 0.002% and 0.004%. Concentrate on. From this, by setting the ratio of the cross-sectional area of the current collector to the coating area of the electrode layer in the range of 0.002% to 0.004%, even if other parameters change to some extent As for the negative electrode plate, an electrode plate (negative electrode plate) having the highest or almost the highest electrode volume output density can be formed.

  In addition, this embodiment is described in order to make an understanding of this invention easy, and does not limit this invention at all. Each element disclosed in the present embodiment includes all design changes and equivalents belonging to the technical scope of the present invention, and various suitable modifications can be made.

FIG. 1 is an overall perspective view of a thin battery according to an embodiment of the present invention. 2 is a cross-sectional view of the thin battery shown in FIG. 1, and is a cross-sectional view taken along the line II of FIG. FIG. 3 is a diagram showing a general configuration of electrode plates such as a positive electrode plate and a negative electrode plate used in the thin battery shown in FIG. FIG. 4 is a diagram showing the relationship of the electrode weight output density with respect to the ratio between the cross-sectional area of the current collector and the coating area of the electrode layer for the positive electrode plate. FIG. 5 is a diagram showing the relationship of the electrode volume output density with respect to the ratio between the cross-sectional area of the current collector and the coating area of the electrode layer for the positive electrode plate. FIG. 6 is a diagram showing the relationship of the electrode weight output density with respect to the ratio between the cross-sectional area of the current collector and the coating area of the electrode layer for the negative electrode plate. FIG. 7 is a diagram showing the relationship of the electrode volume output density with respect to the ratio between the cross-sectional area of the current collector and the coating area of the electrode layer for the negative electrode plate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Thin battery 101 ... Positive electrode plate 101a ... Positive electrode side collector 101b, 101c ... Positive electrode layer 102 ... Separator 103 ... Negative electrode plate 103a ... Negative electrode side collector 103b, 103c ... Negative electrode layer 104 ... Positive electrode tab (positive electrode terminal)
105 ... Negative electrode tab (negative electrode terminal)
DESCRIPTION OF SYMBOLS 106 ... Upper exterior member 107 ... Lower exterior member 108 ... Electric power generation element 111 ... Internal space 201 ... Electrode plate 203a ... Current collector 203b, 203c ... Electrode layer 204 ... Electrode tab 211 ... Current collector blank part

Claims (8)

A positive electrode plate in which a positive electrode layer made of a positive electrode active material mixture is formed on a rectangular positive electrode current collector;
A negative electrode plate in which a negative electrode layer made of a negative electrode active material mixture is formed on a rectangular negative electrode current collector;
A positive electrode terminal connected to a current collector blank portion of the positive electrode current collector;
A secondary battery having a negative terminal connected to the collector margin of the negative electrode current collector,
The cross-sectional area of the positive electrode terminal, Ri 0.006% or less der 0.003% or more of the total formation area of the positive electrode layer per cell,
The cross-sectional area of the positive electrode current collector, a non-aqueous electrolyte secondary battery, wherein said less than 0.006% or der Rukoto 0.003% or more of the total formation area of the positive electrode layer per current collector. 2. The nonaqueous electrolyte secondary battery according to claim 1, wherein a cross-sectional area of the positive electrode terminal is 0.004% or more and less than 0.006% of a total formation area of the positive electrode layer per cell. . 3. The non-aqueous electrolyte 2 according to claim 1 , wherein a cross-sectional area of the negative electrode terminal is 0.002% or more and 0.004% or less of a total formation area of the negative electrode layer per cell. Next battery. The cross-sectional area of the positive electrode current collector, any one of the preceding claims, characterized in that less than 0.004% or more 0.006% or the total formation area of the positive electrode layer per current collector one The non-aqueous electrolyte secondary battery according to item . Sectional area of the negative electrode collector is, non of claim 3 or 4 wherein the per current collector is not more than 0.004% or 0.002% or more of the total formation area of the negative electrode layer Water electrolyte secondary battery. The cross-sectional area of the positive electrode terminal, a non-aqueous electrolyte secondary battery according to any one of claims 1 to 5, characterized in that equal to the sum of the cross-sectional area of the positive electrode current collector. The cross-sectional area of the negative electrode terminal, a non-aqueous electrolyte secondary battery according to any one of claims 1 to 6, characterized in that equal to the sum of the cross-sectional area of the negative electrode current collector. The assembled battery for electric vehicles in which the nonaqueous electrolyte secondary battery as described in any one of Claims 1-7 was connected two or more.

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