Art
[1]
Mutual citations and related applications
[2]
This application claims the benefit of priority based on the date of October 07, 2016 Korea Patent Application No. 10-2016-0130071, and all information disclosed in the literature of the Korea patent application are included as part of the specification.
[3]
Art
[4]
The present invention relates to an electrode unit and a method of manufacturing such an electrode unit.
BACKGROUND
[5]
Repeating the charge and discharge available rechargeable battery (secondary battery) is usually including an electrode assembly (electrode assembly). In this case, the electrode assembly may be prepared by combining the electrode unit (electrode unit).
[6]
1 is a side view illustrating an example of an electrode unit structure according to the prior art. The electrode unit as shown in Figure 1 may include a positive electrode, a separator and an anode. Electrode unit is formed by being laminated in such a positive electrode, a separator and an anode alternately, these electrode units together have an electrode assembly can be produced. On the other hand, the electrode units can be made by a variety of production methods. In one embodiment, the process for preparing the electrode unit may include applying heat to the positive electrode, separator and negative electrode. On the other hand, the positive electrode may be manufactured by coating a cathode active material on both surfaces or one surface of the current collector, the negative electrode may also be prepared by coating a negative electrode active material on both surfaces or one surface of the current collector.
[7]
2 is a side view illustrating an example of an electrode unit manufacturing method according to the prior art.
[8]
As the manufacturing method is lamination (lamination) step of the electrode unit shown in Figure 2, the lamination process is the separation membrane and to then arranged to, or as close to the electrodes abut each other using equipment such as roll heating and / or the pressure membrane and a step of attaching the electrode.
Detailed Description of the Invention
SUMMARY
[9]
On the other hand, when producing an electrode unit, including the step of heating, such as a lamination process, the finished electrode unit is cooled with time. Thus, when producing an electrode unit, including the step of heating the electrode unit is contracted over time. However, the electrode units to each other a plurality of materials including a plurality of different substances, and these are, respectively, because of different coefficients of thermal expansion (coefficient of expansion) are constructed of the electrode units are retracted, each having a different shrinkage as a result the electrode unit is bent this phenomenon will occur.
[10]
Removing step of heating in the process for preparing the electrode unit, or, but may consider a method to lower the degree of applying heat, in this case, the adhesive force and the problem that the strength (stiffness) is reduced in the electrode unit between the membrane and the electrode occurred.
[11]
Accordingly, it is an object to be solved by the present invention even if the electrode unit and the cooling after the step of applying heat producing an electrode unit does not experience the symptoms the electrode unit is bent to the electrode to minimize the developing unit bent.
Problem solving means
[12]
According to a first aspect of the present invention for achieving the above object, according to the manufacturing method of the electrode unit comprising a positive electrode, a negative electrode and a separator, selected for the entire negative electrode current collector included in the total and the negative electrode a positive electrode current collector included in the positive electrode selected steps of; The coating step for coating the active material on each of the entire positive electrode collector and the negative electrode current collector selection of the selection step; And the positive electrode, the separator by heating, and a bonding step for bonding the negative electrode; And wherein the selection step, the electrode unit after the manufacturing doemeuro cooling because of calculating stress (stress) applied to the inside of the whole of the positive electrode current collector and the anode current collector and then, by reflecting the calculation result of the anode the manufacturing method of the collector and the electrode unit for selecting the whole of the negative electrode current collector is provided.
[13]
The selection step, can then according to the positive electrode current collector or the total thickness of the negative electrode current collector calculate the stress applied to the inside of the whole of the positive electrode current collector or the negative electrode current collector is selected for the whole of the positive electrode current collector and the anode current collector have.
[14]
In the selection step, the ratio of the total thickness of the positive electrode current collector for the entire thickness of the negative electrode current collector may be selected for the whole of the positive electrode collector and the negative electrode current collector to be 1.8 to 3.1.
[15]
The cathode current collector may be aluminum, and the anode current collector is copper.
[16]
The bonding step may be bonded to the positive electrode, a separator, and a negative electrode by a lamination (lamination) processes.
[17]
According to a second aspect of the present invention for achieving the above object, according to the manufacturing method of the electrode unit comprising a positive electrode, a negative electrode and a separator, selected for the entire negative electrode current collector included in the total and the negative electrode a positive electrode current collector included in the positive electrode selected steps of; The coating step for coating the active material on each of the entire positive electrode collector and the negative electrode current collector selection of the selection step; And the positive electrode, the separator by heating, and a bonding step for bonding the negative electrode; And wherein the selection step, the electrode unit is then produced due doemeuro cooling the cathode current collector and the anode current collector is contracted by being changed or the cathode of the extent to which the electrode unit bends, the positive electrode collector of the total thickness of the after the calculation in accordance with the change of the thickness of the collector is the manufacturing method of electrode unit for selecting the whole of the positive electrode current collector and the anode current collector is provided.
[18]
In the selection step, the ratio of the total thickness of the positive electrode current collector for the entire thickness of the negative electrode current collector may be selected for the whole of the positive electrode collector and the negative electrode current collector to be 1.8 to 3.1.
[19]
The cathode current collector may be aluminum, and the anode current collector is copper.
[20]
The bonding step may be bonded to the positive electrode, negative electrode and separator by a lamination (lamination) processes.
[21]
According to a third aspect of the present invention for achieving the above object, the electrode unit comprising a positive electrode, a negative electrode and a separator, the positive electrode, the separator, and the negative electrode are bonded together, the positive electrode and the negative electrode is an anode include the entire collector and the anode current collector, and the ratio of the total thickness of the positive electrode current collector for the entire thickness of the negative electrode current collector is provided with an electrode unit from 1.8 to 3.1.
[22]
The cathode current collector may be aluminum, and the anode current collector is copper.
Effects of the Invention
[23]
According to the invention, even if the electrode unit and the cooling after the step of applying heat producing an electrode unit does not experience the symptoms the electrode unit is bent to minimize the phenomenon that the electrode unit bent.
Brief Description of the Drawings
[24]
1 is a side view illustrating an example of an electrode unit structure according to the prior art.
[25]
2 is a side view illustrating an example of an electrode unit manufacturing method according to the prior art.
[26]
Figure 3 is a side view due doemeuro after the manufacture of the electrode unit and the cooling unit has completed the electrode showing the electrode unit is bent appearance.
[27]
4 is a clean them after the experiment the degree of bending the electrode unit in accordance with the change in the ratio (Al / Cu thickness ratio) of the thickness of the aluminum of the copper thickness in the graph of the present invention.
Mode for the Invention
[28]
Reference to the drawings and the like will be described a method for manufacturing electrode unit according to an embodiment of the present invention.
[29]
On the other hand, when the electrode unit is then produced in the course of cooling the bent electrode unit phenomenon When applying heat producing an electrode unit is generated as described above. Developing the electrode unit is bent greatly affected as having a positive electrode collector and the negative electrode collector have different thermal expansion coefficients that make up the particular positive and negative electrodes.
[30]
Figure 3 is a side view due doemeuro after the manufacture of the electrode unit and the cooling unit has completed the electrode showing the electrode unit is bent appearance.
[31]
Electrodes (10, 20) of the electrode unit (1) may include a respective electrode active materials (not shown), and one or both electrode collector (not shown) is applied to the electrode active material. A positive electrode 10 and negative electrode 20 constituting the electrodes can be facing each other while sandwiching the separator 30, the anode 10 and the cathode 20 during the manufacturing process of an electrode unit (1), heat by being applied it can be adhered to the membrane (30). Electrode unit (1) can be produced, for example, by lamination (lamination) processes.
[32]
On the other hand, the positive electrode current collector and the anode current collector may be a different material. Thus, the positive electrode collector there whole and the anode current collector may have different physical properties, in particular, the positive electrode collector and negative electrode collector there is to each other because of having a different coefficient of thermal expansion (coefficient of expansion) shrinkage ratio is different from the cooling process, which because it may result in warpage of the electrode unit.
[33]
For example, the positive electrode collector of the positive electrode 10 may be aluminum, the anode current collector of the negative electrode 20 may be a copper, the coefficient of thermal expansion of aluminum, based on the linear expansion coefficient is 23.1μm * m -1 * K -1 (25 ° C basis), and the coefficient of thermal expansion of copper is 16.5μm * m -1 * K -1 a (25 ° C basis). The total aluminum in the positive electrode current collector to, for example, when the anode current collector is copper, but this description contents can be applied even if the positive electrode current collector or the negative electrode current collector of the other material.
[34]
After applying heat producing an electrode unit (1) the positive electrode collector of aluminum in the course of cooling is relatively much shrinkage as compared to the negative electrode current collector is copper. Thus, it becomes the bend toward the side ends of the electrode unit (1) of aluminum (that is, the positive electrode current collector) as shown in Fig.
[35]
At this time, the degree of aluminum and copper is retracted to aluminum and copper, the generation stress (stress) due to the tension force or shrinking force is different and the degree of the electrode unit is retracted entirely. In other words, aluminum (i.e., a positive electrode collector), a tensile stress due to tensile forces acting in the opposite ends in the negative direction to the shrinkage degree is larger than the extent to which the electrode unit is retracted entirely inside of the aluminum is from the center of the aluminum (tensile stress) is It is generated. In contrast, copper (that is, the anode current collector), the extent of the electrode unit is smaller than the contraction of a whole due to the shrinking force acting inside the copper is in the copper center direction shrinkage stress (compressive stress) contraction is to act.
[36]
Put to sleep, aluminum and copper are more aluminum is greater than a linear expansion coefficient different from the thermal deformation due to temperature changes accordingly copper additional description for clarity. Thus, copper can be seen that applying a tensile stress to the aluminum, the aluminum can be understood conceptually by applying a shrinking stress in the copper.
[37]
This will be described by a formula as follows:
[38]
Stress (stress in the letter, the following, the specification will be referred to as 'σ'.) Is defined as the resistance (P) in a material which acts per unit area (A) of the material. That is, the stress,
[39]
[40]
(Hereinafter referred to as "Equation 1] ')
[41]
[42]
It is defined as.
[43]
In addition, the stress is there also can be expressed in another way, when the material is deformed within the elastic limit (elastic limit) stress, Young's modulus (modulus of elasticity) or the Young's modulus (characters in Young's modulus, hereinafter this specification It will be indicated as 'E'.) and is a strain (strain, unit characters from the deformation amount, or less, the specification of the material per unit length is expressed by the product of will be denoted by 'ε'.). That is, the stress,
[44]
[45]
(Hereinafter, "[Equation 2]")
[46]
[47]
As it may be represented.
[48]
At this time, after the [formula 2] a summary for ε, Substituting Equation 1],
[49]
[50]
(Hereinafter, "[Equation 3]")
[51]
[52]
This is derived.
[53]
On the other hand, the length deformation amount of the material (with the letter in the displacement, or less, this specification will be referred to as 'λ'.) Has a length (characters in length, or less, the specification of that definition, strains and materials with 'L' It is defined as the product of it) to the title. therefore,
[54]
[55]
(Hereinafter, "[Equation 4]")
[56]
[57]
It is derived.
[58]
[59]
On the other hand, the contraction length of the positive electrode collector and the negative full cooling of the house forming the electrode unit (1) shall also be considered together as well as the effects of shrinkage as a function of temperature influence of the stress acting on the material.
[60]
That is, look with reference to Figure 3, aluminum is the value obtained by subtracting the amount of increase in length by the tensile stress in the amount of shrinkage in length depending on the amount of temperature change of the contracted length (i.e., the positive electrode current collector), copper (i. E. , in the amount of shrinkage in length depending on the amount of temperature change of the contracted length of the negative electrode current collector) is a value obtained by adding the amount of contraction in length by shrinkage stress. However, the positive and negative electrodes is so bonded to the same separator can be assumed to be the same as the amount of shrinkage of the length of the retracted length of the aluminum amount of copper. If therefore, the coefficient of thermal expansion of the material relative to the linear expansion coefficient α d and, ΔT the temperature change of the material referred to,
[61]
[62]
(Hereinafter, "[Equation 5]")
[63]
[64]
It is derived.
[65]
At this time, the cathode current collector of its length to the length of the negative electrode current collector is the same (L al = L cu Assuming), and cleanup for the [formula 5] to P,
[66]
[67]
(Hereinafter, "[Equation 6]")
[68]
[69]
This is derived.
[70]
That is, to obtain the resistivity P is applied to the inside of the electrode unit by the [formula 6], the P-resistant α by substituting in Equation 1] al and α cu can be obtained.
[71]
On the other hand, the cathode current collector is aluminum and the negative electrode current collector when the whole copper warping toward the aluminum each end portion of the electrode unit 1 to reduce the degree of bending the electrode unit (1) the amount of deformation of the aluminum λ al is reduced, or the copper deformation [lambda] Cu needs to be increased. In this case, [Formula 2] and [Expression 4] According deformation λ of the aluminum in al to reduce a stress σ of aluminum al be reduced, and the copper amount of deformation λ cu stress σ of copper in order to increase cu necessary to increase a.
[72]
That is, the manufacturing method of the electrode unit including the step of heating the electrode unit in accordance with one embodiment of the present invention, an anode and a doemeuro cathode is cooled stress due applied to the entire interior of the positive electrode collector and the negative electrode current collector (stress) calculating the post, it is possible to reflect the result of the calculation to include the entirety of the selection of the positive electrode collector and negative electrode current collector. That is, it is possible to prevent or minimize the positive electrode collector and the negative electrode collector by the step of selecting the whole so as to include calculating the stress applied to the inside of the positive electrode collector and the negative electrode collector electrode unit is bent by the cooling.
[73]
This method of controlling the whole of the positive electrode collector and negative electrode collector cooling stresses applied to the interior of the can have several. Among these, the inventors of the present invention was identified as a positive electrode collector or negative electrode collector factor is the total thickness of giving a great influence on the stress applied to the inside of the positive electrode collector or negative electrode collector. Table 1 is a cathode current collector is aluminum and the table showing the test results measuring the stress of the stress of the aluminum or copper according to the change in the anode current collector when the total thickness of the copper-aluminum or copper.
[74]
Table 1: measurement of the stress of the stress of the aluminum and copper in accordance with the change in thickness of the aluminum or copper results
The thickness of the aluminum (μm) Copper thickness (μm) Resistance is applied to the inside of the electrode unit (kgf) Stress is applied to the interior of the aluminum (kgf / mm 2 ) Stress is applied to the inside of the copper (kgf / mm 2 )
Reference value (Reference) 12 10 1.5 1.4 1.6
If the thickness of copper decreased by 5 μm 12 5 1.1 1.0 2.3
If the thickness of copper, up 5 μm 12 15 1.8 1.6 1.3
When the thickness of the aluminum down 5 μm 7 10 1.1 1.7 1.2
When the thickness of the aluminum, up 5 μm 17 10 1.8 1.2 2.0

[75]
[76]
Referring to the above table, the thickness of the copper 5μm stress of the aluminum reduction if decreased and became a warpage of the electrode unit alleviated by the stress of the copper is increased, if an increase of the thickness of the aluminum 5μm stress of aluminum decreases and the stress of the copper increase can be confirmed that the warpage phenomenon of the electrode unit by relaxation.
[77]
In particular, if, according to the experimental results, the positive electrode current collector is aluminum and the anode current collector is copper, when the thickness of copper decreased 5μm stress of the aluminum is 1.4kgf / mm 2 at 1.0kgf / mm 2 decreased by about 28%, and stress of the copper is 1.6kgf / mm 2 at 2.3kgf / mm 2 , whereas, up to about 44%, when an increase of the thickness of the aluminum 5μm stress of the aluminum is 1.4kgf / mm 2 at 1.2kgf / mm 2 decreased by about 14% in the stress of the copper is 1.6kgf / mm 2 at 2.0kgf / mm 2 can be confirmed that the increase of about 25%. That is, the inventors of the present invention to reduce the stress of the aluminum and adjust the thickness of the copper rather than to increase the stress of the copper, and to control the thickness of the aluminum alloy in order to mitigate the warpage of the electrode unit through the experiment of the it was found that the more effective.
[78]
To control the copper thickness to effective reason to alleviate the electrode unit warpage than to adjust the thickness of the aluminum is about 1.6 times the Young's modulus of aluminum Young's modulus of copper (Young's modulus) greater (Young's modulus of copper is 110Gpa, the Young's modulus of aluminum is 69Gpa), plate (plate) bending moment (bending moment) across the mold material is that is proportional to the cube of the thickness.
[79]
However, it is not the thickness of the copper is to increase indefinitely the indefinite reduced or the thickness of the aluminum in order to mitigate the warpage of the electrode unit. Because when the thickness of the copper is too low or the thickness of the aluminum increases excessively it can rather be bent portion at both ends of the electrode unit but rather toward the copper (i.e., the negative electrode current collector). Therefore, in order to minimize warpage of the electrode unit it can be confirmed that the ratio is also an important factor of the thickness of the aluminum and the copper thickness.
[80]
4 is a clean them after the experiment the degree of bending the electrode unit in accordance with the change in the ratio (Al / Cu thickness ratio) of the thickness of the aluminum of the copper thickness in the graph of the present invention.
[81]
It can be seen that Figure 4 of the aluminum to the thickness of the copper thickness ratio of the deflection electrode unit when within a predetermined region is substantially prevented as shown in Fig. The inventors of the present invention in the case of aluminum to a thickness of the copper thickness ratio is 1.8 to 3.1 as shown in Figure 4 through the experiment the electrode unit is confirmed that the degree is significantly reduced deflection.
[82]
Will now be described below, the manufacturing method of the electrode unit according to an embodiment of the present invention with reference to the contents of the following:
[83]
Manufacturing method of the electrode unit comprising a positive electrode, a negative electrode and a separator in accordance with one embodiment of the present invention, selection of the positive electrode collector and the selection step, the selection step of selecting the entire negative electrode current collector included in the negative electrode includes a positive electrode a coating step for coating the positive electrode current collector and the anode current collector to the active material, respectively; And the positive electrode, the separator by heating, and may include a bonding step of bonding the negative electrode. In this case, the selection step, then after the bonding step due doemeuro the anode and the cathode is cooled calculating stress (stress) applied to the inside of the whole of the positive electrode collector and the negative electrode current collector, the positive electrode to reflect the result of the calculation the collector and may include selecting the entirety of the negative electrode current collector. In this way as in order to control the stresses applied to the entire interior of the positive electrode collector and the negative electrode current collector, to control the thickness of the positive electrode current collector or the negative electrode current collector in the thickness has the foregoing.
[84]
[85]
The present invention in the above Although the detailed description and specific examples, the invention is not limited thereto, the substrate under the technical scope of the present invention by one of ordinary skill in the art various embodiments within the equivalent scope of the claims to be possible as a matter of course.

Claims
[Claim 1]
In the production method of the electrode unit comprising a positive electrode, a negative electrode and a separator, selecting step of selecting the whole of the anode current collector and the negative electrode included in the total of the positive electrode current collector included in the positive electrode; The coating step for coating the active material on each of the entire positive electrode collector and the negative electrode current collector selection of the selection step; And the positive electrode, the separator by heating, and a bonding step for bonding the negative electrode; And wherein the selection step, the electrode unit after the manufacturing doemeuro cooling because of calculating stress (stress) applied to the inside of the whole of the positive electrode current collector and the anode current collector and then, by reflecting the calculation result of the anode the collector and the method of manufacturing an electrode unit for selecting the whole of the negative electrode current collector.
[Claim 2]
The method according to claim 1, wherein said selection step, said positive electrode current collector or the negative electrode current collector with the thickness of the after calculating the positive electrode current collector or the stress applied to the entire interior of the negative electrode current collector The positive electrode current collector and the anode current collector method for manufacturing an electrode unit for selection of the whole.
[Claim 3]
The method according to claim 2, wherein in the selection step, the manufacturing method of the negative electrode current collector is the ratio of the total thickness of the positive electrode current collector for the entire thickness of the to be 1.8 to 3.1, the cathode current collector and an electrode unit for selecting the whole of the negative electrode current collector.
[Claim 4]
The method according to claim 1, wherein the cathode current collector to the total of aluminum, a method of manufacturing the anode current collector is the copper of the electrode unit.
[Claim 5]
The method according to claim 1, wherein the bonding step is a method of producing an electrode unit for bonding the positive electrode, a separator, and a negative electrode by a lamination (lamination) processes.
[Claim 6]
In the production method of the electrode unit comprising a positive electrode, a negative electrode and a separator, selecting step of selecting the whole of the anode current collector and the negative electrode included in the total of the positive electrode current collector included in the positive electrode; The coating step for coating the active material on each of the entire positive electrode collector and the negative electrode current collector selection of the selection step; And the positive electrode, the separator by heating, and a bonding step for bonding the negative electrode; And wherein the selection step, the electrode unit is then produced due doemeuro cooling the cathode current collector and the anode current collector is contracted by being changed or the cathode of the extent to which the electrode unit bends, the positive electrode collector of the total thickness of the after the calculation in accordance with the change of the thickness of the current collector method for manufacturing an electrode unit for selecting the whole of the positive electrode collector and the negative electrode collector.
[Claim 7]
The method according to claim 6, wherein in the selection step, the manufacturing method of the negative electrode current collector is the ratio of the total thickness of the positive electrode current collector for the entire thickness of the to be 1.8 to 3.1, the cathode current collector and an electrode unit for selecting the whole of the negative electrode current collector.
[Claim 8]
According to claim 6, wherein said positive electrode collector to the total of aluminum, a method of manufacturing the anode current collector is the copper of the electrode unit.
[Claim 9]
The method according to claim 6, wherein the bonding step is a method of producing an electrode unit for bonding the positive electrode, negative electrode and separator by a lamination (lamination) processes.
[Claim 10]
In the electrode unit comprising a positive electrode, a negative electrode and a separator, the total of the positive electrode, the separator, and the negative electrode are bonded to each other, and the positive electrode and the negative electrode comprises the entire respective positive electrode current collector and negative electrode current collector, the anode current collector the ratio of the total thickness of the positive electrode collector to a thickness of 1.8 to 3.1, the electrode unit.
[Claim 11]
The method according to claim 10, wherein the cathode current collector to the total of aluminum, the anode current collector is the copper of the electrode unit.