Battery cell

Abstract

The present application may provide an electric device comprising: a battery cell capable of securing excellent capacity retention, high current output, and appropriate capacity by combining an electrode responsible for high capacity and an electrode responsible for high current output, and capable of flexibly coping with rapidly changing current output conditions while having appropriate capacity; and an electric vehicle including the battery cell and having excellent output and an improved driving range.

Description

battery cell

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Republic of Korea Patent Application No. 10-2024-0008974, filed January 19, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] This application relates to a battery cell. Furthermore, this application relates to applications of the battery cell.

[0005] The performance of a battery can depend on the performance of its functional unit, the battery cell. This performance is determined by the electrodes (anode and cathode) and electrolyte that make up the battery cell. In particular, the type and content of the active material and other materials used in the electrodes can directly impact battery cell performance.

[0006] The present application provides a battery cell that can secure excellent capacity retention, high current output, and appropriate capacity by combining a high-capacity electrode with a high-current output electrode. Furthermore, the present application can provide a battery module or battery pack including the battery cell.

[0007] The present application can provide a battery cell that has an appropriate capacity while flexibly responding to rapidly changing current output conditions. Furthermore, the present application can provide an electric vehicle with excellent output and improved driving range, including a battery cell with these characteristics.

[0008] A battery cell according to one embodiment of the present application includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, wherein the positive electrode includes a first positive electrode and a second positive electrode, the first positive electrode includes a first positive electrode active material layer, the second positive electrode includes a second positive electrode active material layer, and the first positive electrode active material layer and the second positive electrode active material layer each include a positive electrode active material, a positive electrode binder, and a conductive material, and the first positive electrode and the second positive electrode can satisfy at least one of the following conditions.

[0009] [condition]

[0010] Condition i) The positive electrode active material included in the first positive electrode active material layer and the positive electrode active material included in the second positive electrode active material layer are different materials, or condition ii) the content ratios of at least one of the positive electrode active material, positive electrode binder and conductive material included in the first positive electrode active material layer and the second positive electrode active material layer are different, or condition iii) the loading amount (LW1) of the first positive electrode active material composition forming the first positive electrode active material layer and the loading amount (LW2) of the second positive electrode active material composition forming the second positive electrode active material layer are different.

[0011] In a battery cell according to one embodiment of the present application, the first positive electrode includes a first positive electrode tab, the second positive electrode includes a second positive electrode tab, and the first positive electrode tab and the second positive electrode tab can be connected to the same positive electrode lead.

[0012] In a battery cell according to one embodiment of the present application, the second positive electrode has a CP when n is 100 in the following formula R compared to the first positive electrode R,n This could be higher.

[0013] [Formula R]

[0014] CP R,n = CP n / CP1×100

[0015] In formula R, CP nrepresents the n-cycle discharge capacity, and CP1 represents the 1-cycle discharge capacity.

[0016] In a battery cell according to one embodiment of the present application, the ratio (N1 / N2) of the number of first positive electrodes (N1) and the number of second positive electrodes (N2) may be 10 or less.

[0017] In a battery cell according to one embodiment of the present application, the number of the first positive electrodes (N1) is the total number of positive electrodes (N T ) is less than 95% of the total number of anodes (N2), and the number of the second anodes (N2) is less than the total number of anodes (N T ) may be more than 5% (not including 100%).

[0018] In a battery cell according to one embodiment of the present application, the negative electrode includes a first negative electrode and a second negative electrode, the first negative electrode includes a first negative electrode active material layer, the second negative electrode includes a second negative electrode active material layer, the first negative electrode active material layer and the second negative electrode active material layer each include a negative electrode active material, a negative electrode binder, and a conductive material, and the first negative electrode and the second negative electrode may satisfy the following conditions.

[0019] [condition]

[0020] Condition iv) The main compound of the negative electrode active material included in the first negative electrode active material layer and the main compound of the negative electrode active material included in the second negative electrode active material layer have at least one different component element or a different content ratio, or Condition v) The content ratio of at least one of the negative electrode active material, negative electrode binder, and conductive material included in the first negative electrode active material layer and the second negative electrode active material layer is different, or Condition vi) The loading amount (LW3) of the first negative electrode active material composition forming the first negative electrode active material layer and the loading amount (LW4) of the second negative electrode active material composition forming the second negative electrode active material layer are different.

[0021] In a battery cell according to one embodiment of the present application, the first negative electrode includes a first negative electrode tab, the second negative electrode includes a second negative electrode tab, and the first negative electrode tab and the second negative electrode tab can be connected to the same negative electrode lead.

[0022] In a battery cell according to one embodiment of the present application, in condition i), the positive electrode active material included in the first positive electrode active material layer and the positive electrode active material included in the second positive electrode active material layer may be materials in which at least one or more constituent elements are different, or may be materials in which the composition ratios of the elements constituting the chemical formula are different even if they are expressed by the same chemical formula.

[0023] In a battery cell according to one embodiment of the present application, in condition i), the positive electrode active material included in the first positive electrode active material layer and the positive electrode active material included in the second positive electrode active material layer may each independently include at least one compound selected from the group consisting of a compound represented by the following chemical formula P1, a compound represented by the following chemical formula P2, and a compound represented by the following chemical formula P3, and the positive electrode active material included in the first positive electrode active material layer and the positive electrode active material included in the second positive electrode active material layer may differ in at least one element selected from the group consisting of A, M1, M2, and M3 in the following chemical formulas P1, P2, and P3, or may differ in at least one numerical value selected from the group consisting of a, x, y, and z.

[0024] [Chemical formula P1]

[0025] A a M 1x M 2y M 3z O2

[0026] [Chemical formula P2]

[0027] A a M 1x M 2y M 3z (PO4)

[0028] [Chemical formula P3]

[0029] Aa M 1x M 2y M 3z (CN)6

[0030] In the chemical formula P1, chemical formula P2 and chemical formula P3, A is lithium (Li), sodium (Na) or potassium (K), M1, M2 and M3 are at least one selected from the group consisting of nickel (Ni), cobalt (Co), manganese (Mn), iron (Fe), chromium (Cr), vanadium (V), niobium (Nb), boron (B), aluminum (Al), copper (Cu), zirconium (Zr), tungsten (W), titanium (Ti), zinc (Zn), gallium (Ga), germanium (Ge), molybdenum (Mo), tantalum (Ta), yttrium (Y), barium (Ba) and hafnium (Hf) without overlapping each other, x, y and z are each independently 0 or more and 1 or less, and satisfy x+y+z=1, and in the chemical formula P1, a is 0.5 or more and 1.8 or less, and in the chemical formula P2, a is 0.8 or more and 1.2 Below, in chemical formula P3, a is 0.8 or more and 2.2 or less.

[0031] In a battery cell according to one embodiment of the present application, in condition i), the content ratio (W) of the positive electrode active material included in the first positive electrode active material layer PA1 ) and the content ratio of the positive electrode active material contained in the second positive electrode active material layer (W PA2 ) difference (W PA1 -W PA2 ) may be less than or equal to 1 wt%.

[0032] In a battery cell according to one embodiment of the present application, in condition ii), the content ratio (W) of the conductive material included in the first positive electrode active material layer PC1 ) is the content ratio of the conductive material included in the second positive electrode active material layer (W PC2 ) can be greater than.

[0033] In a battery cell according to one embodiment of the present application, in condition ii), the content ratio (W) of the conductive material included in the first positive electrode active material layer PC1) and the content ratio of the conductive material included in the second positive electrode active material layer (W PC2 ) difference (W PC1 -W PC2 ) may be 3 wt% or more.

[0034] In a battery cell according to one embodiment of the present application, in condition ii), the content ratio (W) of the conductive material included in the first positive electrode active material layer PC1 ) and the content ratio of the conductive material included in the second positive electrode active material layer (W PC2 ) may each independently be 10 wt% or less.

[0035] In a battery cell according to one embodiment of the present application, in condition ii), the positive electrode active material included in the first positive electrode active material layer and the positive electrode active material included in the second positive electrode active material layer may include the same material.

[0036] In a battery cell according to one embodiment of the present application, in condition ii), the content ratio (W) of the positive electrode active material included in the first positive electrode active material layer PA1 ) and the content ratio of the positive electrode active material contained in the second positive electrode active material layer (W PA2 ) difference (W PA1 -W PA2 ) may be greater than or equal to 3 wt%.

[0037] In a battery cell according to one embodiment of the present application, in condition ii), the content ratio (W) of the positive electrode active material included in the first positive electrode active material layer PA1 ) and the content ratio of the positive electrode active material contained in the second positive electrode active material layer (W PA2 ) may each independently be 80 wt% or more.

[0038] A battery cell according to one embodiment of the present application includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, wherein the negative electrode includes a first negative electrode and a second negative electrode, the first negative electrode includes a first negative electrode active material layer, the second negative electrode includes a second negative electrode active material layer, and the first negative electrode active material layer and the second negative electrode active material layer each include a negative electrode active material, a negative electrode binder, and a conductive material, and the first negative electrode and the second negative electrode can satisfy at least one of the following conditions.

[0039] [condition]

[0040] Condition iv) The main compound of the negative electrode active material included in the first negative electrode active material layer and the main compound of the negative electrode active material included in the second negative electrode active material layer have at least one different component element or a different content ratio, or Condition v) The content ratio of at least one of the negative electrode active material, negative electrode binder, and conductive material included in the first negative electrode active material layer and the second negative electrode active material layer is different, or Condition vi) The loading amount (LW3) of the first negative electrode active material composition forming the first negative electrode active material layer and the loading amount (LW4) of the second negative electrode active material composition forming the second negative electrode active material layer are different.

[0041] In a battery cell according to one embodiment of the present application, in condition v), the content ratio (W) of the conductive material included in the first negative electrode active material layer NC1 ) and the content ratio of the conductive material included in the second negative electrode active material layer (W NC2 ) difference (W NC1 -W NC2 ) may be 3 wt% or more.

[0042] In a battery cell according to one embodiment of the present application, in condition v), the content ratio (W) of the negative electrode active material included in the first negative electrode active material layer NA1 ) and the content ratio of the negative electrode active material included in the second negative electrode active material layer (W NA2 ) difference (W NA1 -W NA2) may be greater than or equal to 3 wt%.

[0043] A battery cell according to an example of the present application can have excellent capacity retention, high current output, and appropriate capacity by combining electrodes capable of high capacity and electrodes capable of high current output. Furthermore, a battery cell according to an example of the present application can flexibly cope with rapidly changing current output conditions while maintaining an appropriate capacity.

[0044] The drawings presented in this application are based on examples of this application. Furthermore, the ratios of the width, depth, or thickness (or height) of each component are intended to further illustrate the present disclosure, and these ratios may differ from the actual ones. Furthermore, in the coordinate system presented in the drawings, each axis may be perpendicular to each other, with the direction indicated by the arrow being the positive direction, and the direction opposite to the direction indicated by the arrow (rotated 180 degrees) being the negative direction.

[0045] FIG. 1, FIG. 2 and FIG. 3 are each drawings showing at least a portion of a battery cell according to an example of the present application (unidirectional terminal battery cell).

[0046] FIGS. 4, 5 and 6 are each a drawing showing at least a portion of a battery cell according to an example of the present application (bidirectional terminal battery cell).

[0047] Figure 7 is a capacity retention rate graph obtained by performing tests based on battery cells manufactured in Examples 1 to 3, Comparative Examples 1 and 2.

[0048] Figure 8 is a charge / discharge graph obtained based on battery cells manufactured in Examples 1 to 3, Comparative Examples 1 and 2.

[0049] Figure 9 is a capacity retention rate graph obtained based on battery cells manufactured in Example 4, Example 5, and Comparative Example 3.

[0050] Figure 10 is a charge / discharge graph obtained based on battery cells manufactured in Example 4, Example 5, and Comparative Example 3.

[0051] Figure 11 is a capacity retention rate graph obtained based on battery cells manufactured in Example 6 and Comparative Example 4.

[0052] Figure 12 is a charge / discharge graph obtained based on the battery cells manufactured in Example 6 and Comparative Example 4.

[0053] Figure 13 is a graph showing current conditions that simulate the actual behavior of an electric vehicle or hybrid vehicle to evaluate the capacity maintenance rate in the present application.

[0054] Before proceeding with a detailed description of this application, it should be noted that terms and words used in this specification and claims may not be interpreted solely based on their conventional or dictionary meanings. Furthermore, inventors should interpret terms and concepts in a way that aligns with the technical concept of this application, based on the principle that the inventor can appropriately define the concepts of terms to best explain his or her invention. The embodiments described in this specification and the configurations depicted in the drawings represent only the most preferred embodiments of this application and do not necessarily represent the entire technical concept of this application. Therefore, various equivalents and variations may exist at the time of filing of this application.

[0055] The same reference numbers or symbols in each drawing attached to this specification may indicate parts or components that perform substantially the same functions. For convenience of explanation and understanding, the same reference numbers or symbols may be used in different embodiments. In other words, even if components with the same reference numbers are depicted in multiple drawings, they may not all represent a single embodiment.

[0056] In the following description, singular expressions include plural expressions unless the context clearly indicates otherwise. Terms such as "comprise" or "comprises" are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but are to be understood as not excluding in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0057] In addition, in the description below, expressions such as upper, upper, lower, lower, side, front, and rear are expressed based on the direction shown in the drawing, and may be expressed differently if the direction of the object is changed.

[0058] Additionally, terms including ordinal numbers, such as "first," "second," etc., may be used in this specification and claims to distinguish between components. These ordinal numbers are used to distinguish identical or similar components from each other, and the use of these ordinal numbers should not be interpreted in a limited manner. For example, components associated with these ordinals should not be interpreted in a restricted manner, such as in the order of use or arrangement, based on their numbers. If necessary, each ordinal number may be used interchangeably.

[0059] Hereinafter, embodiments of the present application will be described in detail with reference to the attached drawings. However, the scope of the present application may not be limited to the presented embodiments. For example, those skilled in the art who understand the scope of the present application may propose other embodiments within the scope of the present application by adding, modifying, or deleting components, but such embodiments will also be considered within the scope of the present application. The shapes and sizes of elements in the drawings may be exaggerated for clarity.

[0060] In this specification, the term "battery" may be used interchangeably with "cell." Furthermore, the terms "battery" and "cell" may collectively refer to a battery cell, which is a unit thereof, or a battery module or battery pack containing a battery cell. Furthermore, the battery cell according to an example of the present application may be applied without limitation to any technical field that produces current through an electron transport material between an anode and a cathode. For example, the battery cell according to an example of the present application may be applied to the battery field as a secondary battery, as described above, and may also be applied to fuel cells, etc.

[0061] The term "room temperature" used herein refers to the natural temperature that is not heated or cooled. For example, room temperature may mean any temperature within the range of 10°C to 30°C, for example, about 15°C or higher, about 18°C ​​or higher, about 20°C or higher, about 23°C or higher, about 27°C or lower, or 25°C. Unless otherwise specified herein, the unit of temperature is Celsius (°C). In addition, among the physical properties mentioned herein, if the measurement temperature affects the physical property, the physical property is measured at 25°C unless otherwise specified.

[0062] The term "atmospheric pressure" used herein refers to natural pressure that has not been pressurized or depressurized, typically around 700 mmHg to 800 mmHg. Unless otherwise specified herein, the unit of pressure may be mmHg. In addition, if among the physical properties mentioned herein, the measurement pressure affects the physical property, the physical property is measured at atmospheric pressure unless otherwise specified.

[0063] The terms a to b used herein mean between a and b, including a and b. For example, a part by weight to b part by weight means between a part by weight and b part by weight, including a part by weight and b part by weight.

[0064] FIGS. 1, 2, and 3 are each drawings showing at least a portion of a battery cell (10) according to an example of the present application (unidirectional terminal battery cell). FIGS. 4, 5, and 6 are each drawings showing at least a portion of a battery cell according to an example of the present application (bidirectional terminal battery cell).

[0065] The present application can provide a battery cell (10) that can secure excellent capacity retention, high current output, and appropriate capacity by combining electrodes capable of high capacity and electrodes capable of high current output. In addition, the present application can provide a battery cell (10) that can flexibly cope with rapidly changing current output conditions while maintaining an appropriate capacity.

[0066] In addition, the present application can provide a battery module including a battery cell (10), and a battery pack including at least one selected from a group consisting of a battery cell (10) and a battery module. Meanwhile, the present application can provide a battery pack including a battery cell (10) without a battery module, in which case the battery pack can be referred to as a cell-to-pack. In addition, the present application can provide an electric vehicle including a battery cell (10) with excellent output and an improved driving range.

[0067] A battery cell (10) may include one or more positive electrodes (100) and one or more negative electrodes (200). In addition, the battery cell (10) may have a structure in which a separator (300) is interposed between the positive electrode (100) and the negative electrode (200). The battery cell (10) may include one or more electrode assemblies (1000). The electrode assembly (1000) may include a positive electrode (100), a negative electrode (200), and a separator (300).

[0068] The positive electrode (100) may refer to a reduction electrode through which an electron transfer material receives electrons when the battery cell (10) is discharged. The negative electrode (200) may refer to an oxidation electrode through which an electron transfer material transfers electrons when the battery cell (10) is discharged. The separator (300) refers to a membrane through which an electron transfer material can pass while preventing an electrical short circuit between the positive electrode (100) and the negative electrode (200). The electron transfer material may be, for example, lithium ions (Li). + ), sodium ions (Na + ) or potassium ions (K + ) may be.

[0069] The electrode assembly (1000) can be manufactured by winding a positive electrode (100), a negative electrode (200), and a separator (300) in the form of long sheets in the longitudinal direction (so-called winding method). Alternatively, the electrode assembly (1000) can be manufactured by zigzag-bending a separator in the form of a long sheet in the longitudinal direction and then alternately inserting a positive electrode (100) and a negative electrode (200) cut to an appropriate size into the space formed by the bending (so-called zigzag method). Although FIGS. 1 and 4 illustrate examples of electrode assemblies (1000) manufactured by the zigzag method, the electrode assembly (1000) can also be manufactured by the winding method, although not separately illustrated in the drawings. In addition to the winding method or the zigzag method, a method used in the art to manufacture the electrode assembly (1000) can be applied.

[0070] A battery cell (10) can be manufactured by electrically connecting each electrode tab and electrode lead (400) of an electrode assembly (1000) and embedding it in a case (500) together with an electrolyte. In the electrode assembly (1000), the positive electrode tab (110a, 120a) and the positive electrode lead (410) can be electrically connected, and the negative electrode tab (200a) and the negative electrode lead (420) can be electrically connected.

[0071] The battery cell (10) may include an electrode terminal (600) that is part of or electrically connected to the electrode lead (400) and has a structure protruding from the edge of the case (500). The electrode terminal (600) may include a positive terminal (610) that is part of or electrically connected to the positive lead (410) and a negative terminal (620) that is part of or electrically connected to the negative lead (420). FIGS. 1 to 3 illustrate a battery cell (10) in which the positive terminal (610) and the negative terminal (620) protrude in the same direction, and a battery cell (10) having such a structure may be referred to as a unidirectional terminal battery cell (10). FIGS. 4 to 6 illustrate a battery cell (10) in which the positive terminal (610) and the negative terminal (620) protrude in opposite directions, and a battery cell (10) having such a structure may be referred to as a bidirectional terminal battery cell (10). The direction of the terminal (600) is not particularly limited and its position may vary depending on need and design.

[0072] The positive electrode (100) may include a plurality of individual positive electrodes having distinct physical properties. The individual positive electrodes may be described herein as a first positive electrode (110) and a second positive electrode (120), etc. That is, the positive electrode (100) may include a first positive electrode (110) and a second positive electrode (120) having distinct physical properties. Distinct physical properties may mean that there is a difference in physical properties measured with the manufactured battery cells after manufacturing them. Specifically, this may mean that there is a difference in physical properties of the battery cells when only the positive electrode uses the first positive electrode (110) or the second positive electrode (120), and the negative electrode, electrolyte, and physical property measurement method are all the same. Meanwhile, it is obvious to those skilled in the art that the positive electrode (100) may further include a third positive electrode having distinct physical properties from the first positive electrode (110) and the second positive electrode (120). Hereinafter, the first anode (110) and the second anode (120) will be described, but additional individual anodes such as the third anode may include a configuration corresponding to the first anode (110) and the second anode (120), and their descriptions may be referred to.

[0073] One of the first anode (110) and the second anode (120) can generate a relatively high current output. Additionally, one of the first anode (110) and the second anode (120) can have a relatively high capacity.

[0074] Additionally, if one of the first anode (110) and the second anode (120) generates a relatively high current output, the other one may have a relatively high capacity. As will be described later, in the present specification, the first anode (110) may generate a higher current output than the second anode (120), and the second anode (120) may have a higher capacity than the first anode (110).

[0075] The first positive electrode (110) may include a first positive electrode active material layer (110b). The first positive electrode (110) may include a first positive electrode current collector (not shown) and a first positive electrode active material layer (110b) formed on one or both sides of the first positive electrode current collector. The first positive electrode active material layer (110b) may be independently formed on each side of the first positive electrode current collector in a single layer or multi-layer structure. In addition, a region of the first positive electrode (110) where the first positive electrode active material layer (110b) is not formed may be referred to as a first positive electrode non-coated region (110c). Meanwhile, the first positive electrode (110) may include a main body including the first positive electrode active material layer (110b) and the first positive electrode non-coated region (110c), and may include a first positive electrode tab (110a) extending from one edge of the main body.

[0076] Considering the process of the electrode process, the first positive electrode tab (110a) and the first positive electrode non-coated portion (110c) may be a part of the first positive electrode current collector. The material used for the first positive electrode tab (110a) and the first positive electrode non-coated portion (110c) may be the same as the material of the first positive electrode current collector. The type, size, and shape of the first positive electrode current collector are not particularly limited as long as it has electrical conductivity without causing a chemical change in the battery cell (10). The first positive electrode current collector may include at least one selected from the group consisting of aluminum, stainless steel, nickel, titanium, and a material surface-treated with a metal (for example, nickel, titanium, or silver) or carbon on the above materials, and preferably may include aluminum.

[0077] The first positive electrode collector may have an appropriate thickness considering the capacity of the battery cell (10), etc., and may be, for example, about 1 µm to 500 µm or less, about 5 µm to 100 µm or less, or about 8 µm to 30 µm or less.

[0078] The second positive electrode (120) may include a second positive electrode tab (120a), a second positive electrode active material layer (120b), and a second positive electrode non-conductive portion (120c), similar to the first positive electrode (110). The description of the configuration of the second positive electrode (120) may refer to the description of the corresponding configuration of the first positive electrode (110), unless it is contradictory.

[0079] The first anode tab (110a) of the first anode (110) and the second anode tab (120a) of the second anode (120) may be connected to the same anode lead (410). The first anode tab (110a) and the second anode tab (120a) may be electrically connected to the anode lead (410). When there are multiple numbers of at least one of the first anode (110) and the second anode (120), each first anode tab (110a) and each second anode tab (120a) may be electrically connected to the same anode lead (410). In this way, an electrode responsible for a high capacity and an electrode responsible for a high current output can be combined to secure excellent capacity retention, high current output, and appropriate capacity. The electrical connection may be made by aligning the first anode tab (110a) and the second anode tab (120a) and then welding them to the anode lead (410), and may also be pressurized during welding.

[0080] As used herein, "electrically connected" may refer to a state in which, when objects to be connected are connected by a connecting means, an electrical circuit is formed, allowing current to flow between each connected object. The connecting means is not particularly limited as long as it allows for electrical connection, but may be direct contact between the objects to be connected or a wire capable of conducting current.

[0081] The physical properties of the first positive electrode (110) and the second positive electrode (120) can be distinguished by the characteristics of their respective positive electrode active material layers (110b, 120b). The distinct physical properties of the first positive electrode (110) and the second positive electrode (120) can be attributed to their respective positive electrode active material layers (110b, 120b).

[0082] The first positive electrode active material layer (110b) and the second positive electrode active material layer (120b) may each include a positive electrode active material, a positive electrode binder, and a conductive material. The positive electrode active material may include lithium ions (Li + ), sodium ions (Na + ) or potassium ions (K + ) may include a compound capable of reversibly intercalating and deintercalating the positive electrode active material layer (110b, 120b). The positive electrode binder may include a compound capable of improving the internal bonding strength of each positive electrode active material layer (110b, 120b) and improving the adhesion strength of each positive electrode active material layer (110b, 120b) with each positive electrode current collector. The conductive material may include a compound capable of improving the conductivity and ion or electron mobility of each positive electrode active material layer (110b, 120b).

[0083] Meanwhile, each positive electrode active material layer (110b, 120b) is formed by each positive electrode active material composition, and the positive electrode active material composition may be applied onto each positive electrode current collector and then dried to form the positive electrode active material layer (110b, 120b). Unlike the positive electrode active material layer (110b, 120b), the positive electrode active material composition may further include a solvent for processability. In the present specification, drying may mean a process in which the solvent included in the positive electrode active material composition is removed so that the solvent is included in an amount of 1 wt% or less, 0.5 wt% or less, or 0.1 wt% or less relative to the total weight, or is not included at all (i.e., 0 wt%). That is, the positive electrode active material layer (110b, 120b) may mean a state in which the positive electrode active material composition is dried. The drying method is not particularly limited and may be performed by, for example, hot air or infrared irradiation. In addition, the coating can be performed according to a known method, for example, a method using a slot die, a doctor blade method, a dip method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, or a brush coating method. In addition, the positive electrode active material composition can be coated in an appropriate loading amount considering the thickness of the desired positive electrode active material layer (110b, 120b). In addition, the positive electrode active material layer (110b, 120b) can be rolled to miniaturize the battery cell (10) and achieve higher energy density. The rolling can be performed according to a known method, for example, can be performed using a rolling jig.

[0084] The first positive electrode active material layer (110b) may be formed of a first positive electrode active material composition, and the second positive electrode active material layer (120b) may be formed of a second positive electrode active material composition. The first positive electrode active material composition and the second positive electrode active material composition may each independently include a positive electrode active material, a positive electrode binder, and a conductive material, and may also include a solvent. The solvent may be determined according to the materials included in the positive electrode active material composition, and is not particularly limited as long as it is used in the art. The solvent may include, for example, an aqueous solvent such as water (pure water or ultrapure water, etc.), an organic solvent, or a mixed solvent of two or more types.For example, the solvent may be N-methyl-2-pyrrolidone (NMP), propylene carbonate, ethylene carbonate, n-butylene carbonate, dimethyl carbonate, diethyl carbonate, ethylene oxide, gamma-Butyrolactone, 1,2-dimethoxy ethane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, formamide, dimethylformamide, dimethylacetamide, N,N-dimethylaminopropylamine, It may include an organic solvent such as acetonitrile, nitromethane, mMethyl formate, methyl acetate, triethyl phosphate, trimethoxymethane, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, methyl propionate, ethyl propionate, or alcohol, or it may include an aqueous solvent such as water.Preferably, the positive electrode active material composition may include an organic solvent, and specifically may include N-methyl-2-pyrrolinone.

[0085] Meanwhile, the positive electrode active material composition may further include a thickener and / or a dispersant, as needed. For example, the positive electrode active material composition may further include a thickener such as carboxymethyl cellulose (CMC).

[0086] The first anode (110) and the second anode (120) may satisfy at least one of the following conditions. However, if the first anode (110) and the second anode (120) have different physical properties, the first anode (110) and the second anode (120) are not limited to the following conditions and various conditions may be applied to them.

[0087] [condition]

[0088] Condition i) The positive electrode active material included in the first positive electrode active material layer (110b) of the first positive electrode (110) and the positive electrode active material included in the second positive electrode active material layer (120b) of the second positive electrode (120) are different materials.

[0089] Condition ii) The content ratios of at least one of the positive electrode active material, positive electrode binder, and conductive material included in the first positive electrode active material layer (110b) of the first positive electrode (110) and the second positive electrode active material layer (120b) of the second positive electrode (120) are different.

[0090] Condition iii) The loading amount (LW1) of the first positive electrode active material composition forming the first positive electrode active material layer (110b) of the first positive electrode (110) and the loading amount (LW2) of the second positive electrode active material composition forming the second positive electrode active material layer (120b) of the second positive electrode (120) are different.

[0091] As described above, in addition to the above conditions, there may be conditions such as the types of the positive electrode binder included in the first positive electrode active material layer (110b) being different from those of the positive electrode binder included in the second positive electrode active material layer (120b), or the types of the conductive material being different. In addition, there may also be conditions such as the thickness (D1) of the first positive electrode active material layer (110b) of the first positive electrode (110) being different from the thickness (D2) of the second positive electrode active material layer (120b) of the second positive electrode (120). In the present specification, the thickness may be measured using a contact or non-contact (e.g., ultrasonic or laser) thickness measuring device. When the thickness is constant, the value of the constant thickness may mean the thickness of the present specification, and when the thickness is not constant depending on the location, the value of the average thickness may mean the thickness of the present specification. The above average thickness may mean a value obtained by obtaining a thickness profile according to a position, and dividing the area obtained through the profile (a value obtained by integrating the thickness function according to a position over all positions when the vertical axis is thickness and the horizontal axis is position) by the distance moved for the thickness measurement. That is, as long as the properties of the first anode (110) and the second anode (120) can be distinguished, the conditions are not particularly limited.

[0092] In condition i), the fact that the positive electrode active material included in the first positive electrode active material layer (110b) and the positive electrode active material included in the second positive electrode active material layer (120b) of the second positive electrode (120) are different materials may mean materials in which at least one or more constituent elements are different, or may mean materials in which the composition ratios (e.g., molar ratios) of the elements constituting the chemical formula are different even if they are expressed by the same chemical formula.

[0093] Meanwhile, the lithium compound, sodium compound or potassium compound used as the positive electrode active material in the present specification may have a layered structure, a crystal structure or a combination thereof. In addition, the lithium compound in the present specification may be a concept encompassing all compounds in which auxiliary elements, coating elements and doping elements are introduced or substituted with the main active element. The main active element may include, for example, one or more selected from the group consisting of nickel (Ni), cobalt (Co), manganese (Mn) and aluminum (Al). The auxiliary elements, coating elements and doping elements are elements that can improve the structural and chemical stability of the positive electrode active material by combining with the main active element, and may be distinguished according to the method of combining with the main active element. Here, combining with the main active element may include forming a chemical bond with the main active element, or existing on the surface of the positive electrode active material or penetrating from the surface. In addition, for example, the auxiliary elements, the coating elements, and the doping elements may each independently include at least one selected from the group consisting of elements of Group 1, Group 2, Group 13, Group 14, Group 15, Group 16, and transition metals, excluding lithium in the periodic table. Specifically, for example, the auxiliary elements, the coating elements, and the doping elements may each independently include at least one selected from the group consisting of sodium (Na), magnesium (Mg), calcium (Ca), yttrium (Y), titanium (Ti), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), iron (Fe), copper (Cu), silver (Ag), zinc (Zn), boron (B), gallium (Ga), carbon (C), silicon (Si), tin (Sn), strontium (Sr), barium (Ba), radium (Ra), phosphorus (P), and zirconium (Zr).

[0094] In the present specification, the positive electrode active material may include at least one compound selected from the group consisting of a compound represented by the following chemical formula P1, a compound represented by the following chemical formula P2, and a compound represented by the following chemical formula P3.

[0095] [Chemical formula P1]

[0096] A a M 1x M 2y M 3z O2

[0097] In chemical formula P1, A is lithium (Li), sodium (Na), or potassium (K), a is 0.5 or more and 1.8 or less, M1, M2, and M3 are at least one selected from the group consisting of nickel (Ni), cobalt (Co), manganese (Mn), iron (Fe), chromium (Cr), vanadium (V), niobium (Nb), boron (B), aluminum (Al), copper (Cu), zirconium (Zr), tungsten (W), titanium (Ti), zinc (Zn), gallium (Ga), germanium (Ge), molybdenum (Mo), tantalum (Ta), yttrium (Y), barium (Ba), and hafnium (Hf) so as not to overlap each other, and x, y, and z are each independently 0 or more and 1 or less, and satisfy x+y+z=1.

[0098] [Chemical formula P2]

[0099] A a M 1x M 2y M 3z (PO4)

[0100] In chemical formula P2, A is lithium (Li), sodium (Na), or potassium (K), a is 0.8 or more and 1.2 or less, M1, M2, and M3 are at least one selected from the group consisting of nickel (Ni), cobalt (Co), manganese (Mn), iron (Fe), chromium (Cr), vanadium (V), niobium (Nb), boron (B), aluminum (Al), copper (Cu), zirconium (Zr), tungsten (W), titanium (Ti), zinc (Zn), gallium (Ga), germanium (Ge), molybdenum (Mo), tantalum (Ta), yttrium (Y), barium (Ba), and hafnium (Hf) so as not to overlap each other, and x, y, and z are each independently 0 or more and 1 or less, and satisfy x+y+z=1.

[0101] [Chemical formula P3]

[0102] A a M 1x M 2y M 3z (CN)6

[0103] In chemical formula P3, A is lithium (Li), sodium (Na), or potassium (K), a is 0.8 or more and 2.2 or less, M1, M2, and M3 are at least one selected from the group consisting of nickel (Ni), cobalt (Co), manganese (Mn), iron (Fe), chromium (Cr), vanadium (V), niobium (Nb), boron (B), aluminum (Al), copper (Cu), zirconium (Zr), tungsten (W), titanium (Ti), zinc (Zn), gallium (Ga), germanium (Ge), molybdenum (Mo), tantalum (Ta), yttrium (Y), barium (Ba), and hafnium (Hf) so as not to overlap each other, and x, y, and z are each independently 0 or more and 1 or less, and satisfy x+y+z=1.

[0104] In condition i), the positive electrode active material included in the first positive electrode active material layer (110b) and the positive electrode active material included in the second positive electrode active material layer (120b) may each independently include at least one compound selected from the group consisting of a compound represented by the following chemical formula P1, a compound represented by the following chemical formula P2, and a compound represented by the following chemical formula P3. In addition, the positive electrode active material included in the first positive electrode active material layer (110b) and the positive electrode active material included in the second positive electrode active material layer (120b) may differ in at least one element selected from the group consisting of A, M1, M2, and M3 in the following chemical formulas P1, P2, and P3, or may differ in at least one numerical value selected from the group consisting of a, x, y, and z. Through this, the physical properties of the first positive electrode (110) and the second positive electrode (120) can be distinguished.

[0105] [Chemical formula P1]

[0106] A a M 1x M 2y M 3z O2

[0107] [Chemical formula P2]

[0108] A a M 1x M 2y M 3z (PO4)

[0109] [Chemical formula P3]

[0110] A a M 1x M 2y M 3z (CN)6

[0111] In chemical formula P1, chemical formula P2 and chemical formula P3, A is lithium (Li), sodium (Na) or potassium (K), M1, M2 and M3 are at least one selected from the group consisting of nickel (Ni), cobalt (Co), manganese (Mn), iron (Fe), chromium (Cr), vanadium (V), niobium (Nb), boron (B), aluminum (Al), copper (Cu), zirconium (Zr), tungsten (W), titanium (Ti), zinc (Zn), gallium (Ga), germanium (Ge), molybdenum (Mo), tantalum (Ta), yttrium (Y), barium (Ba) and hafnium (Hf) without overlapping each other, x, y and z are each independently 0 or more and 1 or less, and satisfy x+y+z=1, a in chemical formula P1 is 0.5 or more and 1.8 or less, and a in chemical formula P2 is 0.8 or more and 1.2 Below, in chemical formula P3, a is 0.8 or more and 2.2 or less.

[0112] In condition i), the positive electrode active material included in the first positive electrode active material layer (110b) may not be included in the second positive electrode active material layer (120b). For example, the positive electrode active material included in the first positive electrode active material layer (110b) may include a lithium compound, sodium compound, or potassium compound that includes nickel (Ni) as a constituent element. In addition, the positive electrode active material included in the second positive electrode active material layer (120b) may include a lithium compound, sodium compound, or potassium compound that does not include nickel (Ni) as a constituent element.

[0113] In condition i), the positive electrode active material included in the first positive electrode active material layer (110b) may include at least one selected from the group consisting of nickel-cobalt-manganese oxide (NCM), nickel-cobalt-aluminum oxide (NCA), and nickel-cobalt-manganese-aluminum oxide (NCMA). Nickel-cobalt-manganese oxide (NCM), nickel-cobalt-aluminum oxide (NCA), and nickel-cobalt-manganese-aluminum oxide (NCMA) may each be independently combined with lithium (Li), sodium (Na), or potassium (K).

[0114] Nickel (Ni) is one of the transition metals related to the output and capacity of a battery cell, and the positive electrode active material included in the first positive electrode active material layer (110b) may have a high nickel content (so-called high nickel). However, if only the nickel (Ni) content is increased, there is a problem that the storage stability and lifespan stability of the battery cell rapidly deteriorate, and side reactions with the electrolyte may increase, causing electrolyte consumption. Therefore, an appropriate content of cobalt (Co), manganese (Mn), or aluminum (Al) may be used as the main active element as the positive electrode active material.

[0115] A high nickel content ratio may mean that when the total number of moles of the main active element in the positive electrode active material is 1 mole (mol), nickel (Ni) is 0.6 mole or more, 0.65 mole or more, 0.7 mole or more, 0.75 mole or more, 0.8 mole or more, 0.82 mole or more, 0.83 mole or more, 0.84 mole or more, 0.85 mole or more, or 0.88 mole or more, or 0.95 mole or less, 0.94 mole or less, 0.93 mole or less, 0.92 mole or less, 0.91 mole or less, or 0.9 mole or less.

[0116] In condition i), the positive electrode active material included in the second positive electrode active material layer (120b) may include at least one selected from the group consisting of cobalt oxide (LCO), manganese oxide (LMO), and iron phosphate (LFP). The cobalt oxide (LCO), manganese oxide (LMO), and iron phosphate (LFP) may each be independently combined with lithium (Li), sodium (Na), or potassium (K).

[0117] It is known that the positive electrode active material that can be included in the first positive electrode active material layer (110b) can generate a relatively high current output compared to the positive electrode active material that can be included in the second positive electrode active material layer (120b). Therefore, the first positive electrode (110) can generate a high current output compared to the second positive electrode (120).

[0118] Meanwhile, it is known that the positive electrode active material that can be included in the second positive electrode active material layer (120b) can have a relatively high capacity compared to the positive electrode active material that can be included in the first positive electrode active material layer (110b). Therefore, the second positive electrode (120) can have a high capacity compared to the first positive electrode (110). By combining the first positive electrode (110) and the second positive electrode (120) having such characteristics and electrically connecting them with the same positive electrode lead (410), excellent capacity retention, high current output, and appropriate capacity can be secured.

[0119] Although not particularly limited, for example, in condition i), the positive electrode active material included in the first positive electrode active material layer (110b) and the positive electrode active material included in the second positive electrode active material layer (120b) may be different, and other conditions may be substantially the same.

[0120] For example, one or more or all of the positive electrode active material, the binder, and the conductive material included in each of the first positive electrode active material layer (110b) and the second positive electrode active material layer (120b) may have substantially the same content ratio. Here, the substantially same content ratio means that the absolute value of the difference in the content ratio of each component included in the first positive electrode active material layer (110b) and the second positive electrode active material layer (120b) may be 1% or less, 0.5% or less, or 0.1% or less. In the present specification, the content ratio may mean the weight % of the corresponding material included relative to the total weight.

[0121] For example, in condition i), the content ratio (W) of the positive electrode active material included in the first positive electrode active material layer (110b) PA1 ) and the content ratio (W) of the positive electrode active material included in the second positive electrode active material layer (120b) PA2 ) difference (W PA1 -W PA2) may be 1% or less, 0.5% or less, or 0.1% or less. In addition, the content ratio (W) of the positive electrode binder included in the positive electrode active material layer (110b) in condition i) PB1 ) and the content ratio (W) of the positive electrode binder included in the second positive electrode active material layer (120b) PB2 ) difference (W PB1 -W PB2 ) may be 1% or less, 0.5% or less, or 0.1% or less. In addition, the content ratio (W) of the conductive material included in the 1 positive electrode active material layer (110b) in condition i) PC1 ) and the content ratio of the conductive material included in the second positive electrode active material layer (120b) (W PC2 ) difference (W PC1 -W PC2 ) may be less than or equal to 1%, less than or equal to 0.5%, or less than or equal to 0.1%.

[0122] Although not particularly limited, for example, in condition i), the positive electrode active material included in the first positive electrode active material layer (110b) and the second positive electrode active material layer (120b) may independently be included in an amount of 80 wt% or more, 81 wt% or more, 82 wt% or more, 83 wt% or more, 84 wt% or more, 85 wt% or more, 86 wt% or more, 87 wt% or more, 88 wt% or more, 89 wt% or more, 90 wt% or more, 91 wt% or more, 92 wt% or more, 93 wt% or more, 94 wt% or more, 95 wt% or more, or 96 wt% or more, or 99 wt% or less or 98 wt% or less, based on the total weight. The content ratio of the positive electrode active material may be within a range formed by appropriately selecting the above-mentioned upper and lower limits. When the content ratio of the positive electrode active material satisfies the above range, it is possible to secure an appropriate energy capacity while generating excellent current output. In addition, when using a single anode (100) without an individual anode, the content of the anode active material included in the anode active material layer may refer to the aforementioned content. Hereinafter, when using a single anode (100), the type and content of each component included in the anode active material layer may be referred to.

[0123] Although not particularly limited, for example, in condition i), the positive electrode binder included in the first positive electrode active material layer (110b) and the second positive electrode active material layer (120b) may be independently included in an amount of 0.1 part by weight or more, 0.5 parts by weight or more, 1 part by weight or more, 2 parts by weight or more, 3 parts by weight or more, 4 parts by weight or more, or 5 parts by weight or more, or 20 parts by weight or less, 19 parts by weight or less, 18 parts by weight or less, 17 parts by weight or less, 16 parts by weight or less, 15 parts by weight or less, 14 parts by weight or less, 13 parts by weight or less, 12 parts by weight or less, 11 parts by weight or less, or 10 parts by weight or less, based on 100 parts by weight of the positive electrode active material. The content ratio of the positive electrode binder may be within a range formed by appropriately selecting the above-mentioned upper and lower limits. When the content ratio of the positive electrode binder satisfies the above range, the internal bonding force of the positive electrode active material layer can be increased, the adhesion with the positive electrode current collector can be improved, and stability can be secured.

[0124] In addition, for example, in condition i), the positive electrode binders included in the first positive electrode active material layer (110b) and the second positive electrode active material layer (120b) are each independently selected from the group consisting of polyvinylidene fluoride (PVDF), polyvinyl alcohol, styrene butadiene rubber (SBR), polyethylene oxide, carboxyl methyl cellulose (CMC), cellulose acetate, cellulose acetate butylate, cellulose acetate propionate, cyanoethylpullulan, cyanoethyl polyvinylalcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, It may include at least one selected from the group consisting of polymethylmethacrylate, polybutylacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, and polyarylate, but is not limited thereto.It may be preferable that the positive electrode binder included in the first positive electrode active material layer (110b) and the second positive electrode active material layer (120b) each independently include at least one selected from the group consisting of polyvinylidene fluoride (PVDF), polyvinyl alcohol, styrene butadiene rubber (SBR), and polyethylene oxide. Here, polyvinylidene fluoride (PVDF) may include not only mono-polyvinylidene fluoride but also a copolymer copolymerized with hexafluoropropene (HFP) or chlorotrifluoroethylene (CTFE).

[0125] Although not particularly limited, for example, in condition i), the conductive material included in the first positive electrode active material layer (110b) and the second positive electrode active material layer (120b) may be independently included in an amount of 0.1 part by weight or more, 0.5 part by weight or more, 1 part by weight or more, 2 parts by weight or more, 3 parts by weight or more, 4 parts by weight or more, or 5 parts by weight or more, or 20 parts by weight or less, 19 parts by weight or less, 18 parts by weight or less, 17 parts by weight or less, 16 parts by weight or less, 15 parts by weight or less, 14 parts by weight or less, 13 parts by weight or less, 12 parts by weight or less, 11 parts by weight or less, or 10 parts by weight or less, based on 100 parts by weight of the positive electrode active material. The content ratio of the conductive material may be within a range formed by appropriately selecting the above-mentioned upper and lower limits. When the content ratio of the conductive material satisfies the above range, better conductivity can be provided.

[0126] In addition, for example, the conductive materials included in the first positive electrode active material layer (110b) and the second positive electrode active material layer (120b) in condition i) are not particularly limited as long as they are independently used in the art, and may include carbon-based conductive materials such as graphite, carbon black, acetylene black, Ketjen black, graphene, carbon nanotubes (CNTs), vapor-grown carbon fibers (VGCFs), and carbon fibers, and / or metal-based conductive materials including perovskite materials such as tin, tin oxide, titanium oxide, LaSrCoO3, and LaSrMnO3. The carbon nanotubes (CNTs) may include one or more selected from the group consisting of multi-walled carbon nanotubes (MWCNTs) and single-walled carbon nanotubes (SWCNTs) depending on the number of walls.

[0127] In condition ii), the content ratio (W) of the conductive material included in the first positive electrode active material layer (110b) of the first positive electrode (110) PC1 ) is the content ratio (W) of the conductive material included in the second positive electrode active material layer (120b) of the second positive electrode (120). PC2 ) may be greater than that. As described above, the conductive material can improve conductivity and ion or electron mobility, so that an increase in the content of the conductive material may be advantageous for current output. On the other hand, an increase in the content of the conductive material may be disadvantageous in terms of capacity because, conversely, the content ratio of the positive electrode active material decreases as a result. That is, the physical properties of the first positive electrode (110) and the second positive electrode (120) can be distinguished by varying the content of the conductive material included in each positive electrode active material layer (110b, 120b).

[0128] In condition ii), the content ratio (W) of the conductive material included in the first positive electrode active material layer (110b) of the first positive electrode (110) PC1) and the content ratio (W) of the conductive material included in the second positive electrode active material layer (120b) of the second positive electrode (120) PC2 ) difference (W PC1 -W PC2 ) may be 3 wt% or more, 3.2 wt% or more, 3.4 wt% or more, 3.6 wt% or more, 3.8 wt% or more, or 4 wt% or more, or 9.5 wt% or less, 9 wt% or less, 8 wt% or less, 7 wt% or less, 6 wt% or less, or 5 wt% or less. The difference in the content ratio of the conductive material (W PC1 -W PC2 ) may be within a range formed by appropriately selecting the upper and lower limits described above. That is, the properties of the first positive electrode (110) and the second positive electrode (120) may be distinguished by varying the content of the conductive material included in each positive electrode active material layer (110b, 120b).

[0129] In condition ii), the content ratio (W) of the conductive material included in the first positive electrode active material layer (110b) of the first positive electrode (110) PC1 ) and the content ratio (W) of the conductive material included in the second positive electrode active material layer (120b) of the second positive electrode (120) PC2 ) may be independently 10 wt% or less, 9.5 wt% or less, 9 wt% or less, 8.5 wt% or less, 8 wt% or less, 7.5 wt% or less, 7 wt% or less, 6.5 wt% or less, 6 wt% or less, 5.5 wt% or less, or 5 wt% or less, or 0.1 wt% or more, 0.5 wt% or more, or 1 wt% or more. The content ratio of the conductive material may be within a range formed by appropriately selecting the above-mentioned upper and lower limits. The type of the conductive material may refer to the contents described in the above-mentioned condition i).

[0130] In condition ii), the positive electrode active material included in the first positive electrode active material layer (110b) of the first positive electrode (110) and the positive electrode active material included in the second positive electrode active material layer (120b) of the second positive electrode (120) may include the same material. Here, the same material may mean a lithium compound having the same main active element. That is, even if the ratio (e.g., molar ratio) between elements in the lithium compound is different, if the main active elements are the same, they may be viewed as the same material. For example, lithium nickel-cobalt-manganese oxide (NCM) having nickel (Ni):cobalt (Co):manganese (Mn) in a ratio of 8:1:1 (mol) and lithium nickel-cobalt-manganese oxide (NCM) having nickel (Ni):cobalt (Co):manganese (Mn) in a ratio of 6:2:2 (mol) can be viewed as the same material in condition ii) because the main active elements are nickel, cobalt, and manganese.

[0131] In condition ii), the positive electrode active material included in the first positive electrode active material layer (110b) of the first positive electrode (110) and the positive electrode active material included in the second positive electrode active material layer (120b) of the second positive electrode (120) are the same material, and may include at least one selected from the group consisting of lithium nickel-cobalt-manganese oxide (NCM), lithium nickel-cobalt-aluminum oxide (NCA), lithium nickel-cobalt-manganese-aluminum oxide (NCMA), lithium cobalt oxide (LCO), lithium manganese oxide (LMO), and lithium iron phosphate (LFP). For details on the positive electrode active material, refer to the contents described in the aforementioned condition i).

[0132] In condition ii), the content ratio (W) of the positive electrode active material included in the first positive electrode active material layer (110b) of the first positive electrode (110) PA1 ) and the content ratio (W) of the positive electrode active material contained in the second positive electrode active material layer (120b) of the second positive electrode (120) PA2 ) difference (W PA1 -W PA2) may be 3 wt% or more, 3.5 wt% or more, 4 wt% or more, 4.5 wt% or more, 5 wt% or more, 5.5 wt% or more, 6 wt% or more, 6.5 wt% or more, 7 wt% or more, 7.5 wt% or more or 8 wt% or more, or may be 9.5 wt% or less, 9 wt% or less or 8.5 wt% or less, but is not particularly limited. In condition ii), the difference in the content ratio of the positive electrode active material (W PA1 -W PA2 ) can be within a range formed by appropriately selecting the upper and lower limits described above.

[0133] Although not particularly limited, for example, in condition ii), the positive electrode active material included in the first positive electrode active material layer (110b) and the second positive electrode active material layer (120b) may independently be included in an amount of 80 wt% or more, 81 wt% or more, 82 wt% or more, 83 wt% or more, 84 wt% or more, 85 wt% or more, 86 wt% or more, 87 wt% or more, 88 wt% or more, 89 wt% or more, 90 wt% or more, 91 wt% or more, 92 wt% or more, 93 wt% or more, 94 wt% or more, 95 wt% or more, or 96 wt% or more, or 99 wt% or less or 98 wt% or less, based on the total weight. The content ratio of the positive electrode active material may be within a range formed by appropriately selecting the above-mentioned upper and lower limits. When the content ratio of the positive electrode active material satisfies the above range, it is possible to secure an appropriate energy capacity while generating excellent current output.

[0134] Although not particularly limited, for example, in condition ii), the positive electrode binder included in the first positive electrode active material layer (110b) and the second positive electrode active material layer (120b) may be independently included in an amount of 0.1 part by weight or more, 0.5 parts by weight or more, 1 part by weight or more, 2 parts by weight or more, 3 parts by weight or more, 4 parts by weight or more, or 5 parts by weight or more, or 20 parts by weight or less, 19 parts by weight or less, 18 parts by weight or less, 17 parts by weight or less, 16 parts by weight or less, 15 parts by weight or less, 14 parts by weight or less, 13 parts by weight or less, 12 parts by weight or less, 11 parts by weight or less, or 10 parts by weight or less, based on 100 parts by weight of the positive electrode active material. The content ratio of the positive electrode binder may be within a range formed by appropriately selecting the above-mentioned upper and lower limits. When the content ratio of the positive electrode binder satisfies the above range, the internal bonding force of the positive electrode active material layer can be increased, the adhesion with the positive electrode current collector can be improved, and stability can be secured. The type of positive electrode binder can be referred to as described in condition i) above.

[0135] Meanwhile, the first anode (110) and the second anode (120) are CP when n is 100 in the following formula R R,n can be distinguished. The second anode (120) has a CP when n is 100 in the following formula R compared to the first anode (110). R,n This could be higher.

[0136] [Formula R]

[0137] CP R,n = CP n / CP1×100

[0138] In formula R, CP nmeans n-cycle discharge capacity, and CP1 means 1-cycle discharge capacity. The method of measuring the cycle discharge capacity is not particularly limited as long as it is used in the art. For example, the cycle discharge capacity can be measured by charging at 0.3C to a voltage (charge voltage) corresponding to SOC98 under constant current / constant voltage (CC / CV) conditions under the condition that 25 ℃ is maintained, then cutting off at 0.05C, discharging at 0.3C to a voltage (discharge voltage) corresponding to SOC4 under constant current (CC) conditions, and measuring the discharge capacity. Alternatively, for example, the cycle discharge capacity can be measured according to the capacity retention evaluation method in the [Method for Measuring Physical Properties] below (see FIG. 13). In addition, the cycle discharge capacity according to the formula R can be measured for a battery cell including a first positive electrode (110) or a second positive electrode (120). Here, for comparison, a battery cell is manufactured by changing only the type of positive electrode and the negative electrode and electrolyte as well as the physical property measurement method, and then the cycle discharge capacity can be measured by referring to the method described above.

[0139] The second anode (120) has a CP when n is 100 in the following formula R compared to the first anode (110). R,n To make this higher, the constituent elements or content ratios of the positive electrode active material included in the first positive electrode active material layer (110b) and the positive electrode active material included in the second positive electrode active material layer (120b) can be appropriately selected to be different. In addition, the content ratios of at least one of the positive electrode active material, positive electrode binder, and conductive agent included in each of the first positive electrode active material layer (110b) and the second positive electrode active material layer (120b) can be appropriately selected to be different.

[0140] The ratio (N1 / N2) of the number of first anodes (N1) to the number of second anodes (N2) may be 10 or less, 9 or less, 8 or less, 7 or less, 6 or less, or 5 or less, or 0.1 or more, 0.5 or more, 1 or more, 2 or more, 3 or more, or 4 or more. The ratio (N1 / N2) of the number of first anodes (110) and second anodes (120) may be within a range formed by appropriately selecting the above-mentioned upper and lower limits. When the ratio (N1 / N2) of the number of first anodes (110) and second anodes (120) satisfies the above-mentioned range, individual anodes having distinct physical properties can be combined to secure excellent capacity retention, high current output, and appropriate capacity. Meanwhile, the number of the first anode (N1) and the number of the second anode (N2) can be measured for the first anode (110) and the second anode (120) connected to the same anode lead (410).

[0141] The number of the first anode (N1) is the total number of anodes (N T ) may be 95% or less, 90% or less, 85% or less, 80% or less, 75% or less, 70% or less, 65% or less, 60% or less, 55% or less, or 50% or less, or 5% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, or 45% or more (excluding 100%). The number of first anodes (N1) may be within a range formed by appropriately selecting the above-mentioned upper and lower limits. The total number of anodes (N T ) means the total number of anodes, including the first anode (110) and the second anode (120) connected to the same anode lead (410), and the number of first anodes (N1) means the number of first anodes (110) connected to the anode lead (410).

[0142] The number of second anodes (N2) is the total number of anodes (N T) may be 95% or less, 90% or less, 85% or less, 80% or less, 75% or less, 70% or less, 65% or less, 60% or less, 55% or less, or 50% or less, or 5% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, or 45% or more (excluding 100%). The number of second anodes (N2) may be within a range formed by appropriately selecting the above-mentioned upper and lower limits. The total number of anodes (N T ) means the total number of anodes, including the first anode (110) and the second anode (120) connected to the same anode lead (410), and the number of second anodes (N2) means the number of second anodes (120) connected to the anode lead (410).

[0143] The total number of positive poles (N) T ) The number of the first anode (N1) and the number of the second anode (N2) are naturally affected by the number of the first anode (110) and the second anode (120). For example, in an anode (100) including only the first anode (110) and the second anode (120), the first anode (110) is the number of the total anodes (N T ) is provided in a quantity of about 60% of the total number of anodes (N), the second anode (120) is T ) is prepared in a quantity of about 40% of the total.

[0144] The negative electrode (200) may include a negative electrode active material layer (200b). The negative electrode (200) may include a negative electrode current collector (not shown) and a negative electrode active material layer (200b) formed on one or both sides of the negative electrode current collector. The negative electrode active material layer (200b) may be independently formed on each side of the negative electrode current collector in a single layer or multi-layer structure. In addition, a region of the negative electrode (200) where the negative electrode active material layer (200b) is not formed may be referred to as a negative electrode non-conductive region (200c). Meanwhile, the negative electrode (200) may include a main body including the negative electrode active material layer (200b) and the negative electrode non-conductive region (200c), and may include a negative electrode tab (200a) extending from one edge of the main body.

[0145] Considering the process of the electrode manufacturing process, the negative electrode tab (200a) and the negative electrode non-coated portion (200c) may be a part of the negative electrode current collector. The material used for the negative electrode tab (200a) and the negative electrode non-coated portion (200c) may be the same as the material of the negative electrode current collector. The type, size, and shape of the negative electrode current collector are not particularly limited as long as it has electrical conductivity without causing a chemical change in the battery cell (10). The negative electrode current collector may include at least one selected from the group consisting of copper, stainless steel, nickel, titanium, and materials surface-treated with a metal (for example, nickel, titanium, or silver) or carbon on the above materials, and preferably may include copper.

[0146] The negative electrode current collector may have an appropriate thickness considering the capacity of the battery cell (10), etc., and may be, for example, about 1 ㎛ to 500 ㎛ or less, 5 ㎛ to 100 ㎛ or less, or 8 ㎛ to 50 ㎛ or less.

[0147] The negative electrode (200) may include a plurality of individual negative electrodes having distinct physical properties. The individual negative electrodes may be described herein as a first negative electrode and a second negative electrode, etc. That is, the negative electrode (200) may include a first negative electrode and a second negative electrode having distinct physical properties. Distinct physical properties may mean that there is a difference in the physical properties measured with the manufactured battery cells after they are manufactured. Specifically, this may mean that there is a difference in the physical properties of the battery cells when only the negative electrode uses the first negative electrode or the second negative electrode, and the positive electrode, electrolyte, and physical property measurement method are all the same. Meanwhile, it is obvious to those skilled in the art that the negative electrode (200) may further include a third negative electrode having distinct physical properties from the first negative electrode and the second negative electrode. Hereinafter, the first negative electrode and the second negative electrode will be described, but additional individual negative electrodes such as the third negative electrode may include a configuration corresponding to the first negative electrode and the second negative electrode, and reference may be made to their descriptions.

[0148] One of the first cathode and the second cathode may have a relatively high capacity. Furthermore, one of the first cathode and the second cathode may generate a relatively high current output. Furthermore, if one of the first cathode and the second cathode generates a relatively high current output, the other may have a relatively high capacity. For example, in the present specification, the first cathode may generate a higher current output than the second cathode, and the second cathode may have a higher capacity than the first cathode.

[0149] The first negative electrode and the second negative electrode may refer to the structure of the aforementioned negative electrode (200) as long as they are not contradictory, and may each independently include a negative electrode active material layer. That is, the first negative electrode may include a first negative electrode active material layer, and the second negative electrode may include a second negative electrode active material layer.

[0150] The first negative electrode may include a first negative electrode tab, and the second negative electrode may include a second negative electrode tab. The first negative electrode tab and the second negative electrode tab may be connected to the same negative electrode lead (420). The first negative electrode tab and the second negative electrode tab may be electrically connected to the negative electrode lead (420). When there are multiple first and second negative electrodes, each first negative electrode tab and each second negative electrode tab may be electrically connected to the same negative electrode lead (420). Thus, by combining negative electrodes with different physical properties, excellent capacity retention, high current output, and appropriate capacity can be secured. The electrical connection may be achieved by aligning the second negative electrode tab and the second negative electrode tab and then welding them to the negative electrode lead (420), and may be performed under pressure during welding.

[0151] The first negative electrode and the second negative electrode can have different physical properties depending on the characteristics of their respective negative electrode active material layers. The different physical properties of the first negative electrode and the second negative electrode can be attributed to their respective negative electrode active material layers.

[0152] The first negative electrode active material layer and the second negative electrode active material layer may each include a negative electrode active material, a negative electrode binder, and a conductive material. The negative electrode active material may include a compound capable of reversibly intercalating and deintercalating lithium ions, sodium ions, or potassium ions. The negative electrode binder may include a compound capable of improving the internal cohesion of each negative electrode active material layer and improving the adhesion of each negative electrode active material layer to each negative electrode current collector. The conductive material may include a compound capable of improving the conductivity and ion or electron mobility of each negative electrode active material layer.

[0153] Each negative electrode active material layer is formed by each negative electrode active material composition, and the negative electrode active material composition can be formed by coating and drying on each negative electrode current collector. Unlike the negative electrode active material, the negative electrode active material composition may further include a solvent for processability. The negative electrode active material layer may refer to a state in which the negative electrode active material composition is dried. The drying method is not particularly limited and may be performed by, for example, hot air or infrared irradiation. In addition, the coating may be performed according to a known method, and may be performed by, for example, a method using a slot die, a doctor blade method, a dip method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, or a brushing method. In addition, the negative electrode active material composition may be coated in an appropriate loading amount considering the desired thickness of the negative electrode active material layer. In addition, the negative electrode active material layer may be rolled for miniaturization of the battery cell (10) and higher energy density. The above rolling can be performed in a known manner, for example, through a rolling jig.

[0154] The first negative electrode active material layer may be formed of a first negative electrode active material composition, and the second negative electrode active material layer may be formed of a second negative electrode active material composition. The first negative electrode active material composition and the second negative electrode active material composition may each independently include a negative electrode active material, a negative electrode binder, and a conductive agent, and may also include a solvent. The solvent may include, for example, an aqueous solvent such as water (pure water or ultrapure water, etc.), an organic solvent, or a mixed solvent of two or more types.For example, the solvent may include an aqueous solvent such as water, or may include a solvent such as N-methyl-2-pyrrolidone (NMP), propylene carbonate, ethylene carbonate, n-butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma-Butyrolactone, 1,2-dimethoxy ethane, tetrahydrofuran, 2-methyltetrahydrofuran, diMethyl sulfoxide, formamide, dimethylformamide, acetonitrile, nitromethane, mMethyl formate, It may include an organic solvent such as methyl acetate, triethyl phosphate, trimethoxymethane, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, methyl propionate, ethyl propionate, or alcohol. Preferably, the negative active material composition may include an aqueous solvent, and specifically, may include water (pure water or ultrapure water).

[0155] Meanwhile, the negative active material composition may further include a thickener and / or a dispersant, as needed. For example, the negative active material composition may include a cellulose-based compound as a thickener, and the cellulose-based compound may include at least one selected from the group consisting of, for example, carboxyl methyl cellulose (CMC), cellulose acetate, cellulose acetate butylate, and cellulose acetate propionate.

[0156] The first cathode and the second cathode may satisfy at least one of the following conditions. However, if the first cathode and the second cathode can have different physical properties, the first cathode and the second cathode are not limited to the following conditions and various conditions may be applied to them.

[0157] [condition]

[0158] Condition iv) The main compound of the negative active material included in the first negative active material layer of the first negative electrode and the main compound of the negative active material included in the second negative active material layer of the second negative electrode are different in at least one component element or have different content ratios.

[0159] Condition v) The content ratios of at least one of the negative electrode active material, negative electrode binder, and conductive material included in the first negative electrode active material layer of the first negative electrode and the second negative electrode active material layer of the second negative electrode are different.

[0160] Condition vi) The loading amount (LW3) of the first negative electrode active material composition forming the first negative electrode active material layer of the first negative electrode and the loading amount (LW4) of the second negative electrode active material composition forming the second negative electrode active material layer of the second negative electrode are different.

[0161] As described above, in addition to the above conditions, there may be conditions such as the types of the negative electrode binder included in the first negative electrode active material layer and the negative electrode binder included in the second negative electrode active material layer being different, or the types of the conductive material being different. In addition, there may also be a condition such that the thickness (D3) of the first negative electrode active material layer of the first negative electrode and the thickness (D4) of the second negative electrode active material layer of the second negative electrode are different. In other words, as long as the physical properties of the first negative electrode and the second negative electrode can be distinguished, the conditions are not particularly limited.

[0162] Meanwhile, in the present specification, the negative electrode active material may include at least one selected from the group consisting of a silicon-based compound, a carbon-based compound, and an additional negative electrode active material, and these may include a state in which a metal is doped or coated. The metal element used for doping or coating may include, for example, at least one selected from the group consisting of lithium (Li), magnesium (Mg), calcium (Ca), iron (Fe), titanium (Ti), vanadium (V), and aluminum (Al). In the present specification, a silicon-based compound may mean a compound that is capable of reversible intercalation and deintercalation of lithium ions, sodium ions, or potassium ions and includes a silicon element (Si), unless limited thereto. In addition, in the present specification, a carbon-based compound may mean a compound that is capable of reversible intercalation and deintercalation of lithium ions, sodium ions, or potassium ions and includes a carbon element (C), unless limited thereto. If it contains both silicon elements (Si) and carbon elements (C), it can be classified as a silicon compound.

[0163] Silicon compounds are, for example, SiOx(0 <x≤2)의 구조식을 가진 화합물을 포함할 수 있다. 또한, 실리콘계 화합물은 전술한 바와 같이 결정질 탄소 또는 비정질 탄소와 실리콘이 결합된 실리콘 탄화물을 포함할 수 있다. 상기 결정질 탄소는 무정형, 판상, 플레이크(flake), 구형 또는 섬유형의 천연 흑연 또는 인조 흑연과 같은 흑연을 예로 들 수 있다. 또한, 상기 비정질 탄소는 소프트 카본, 하드 카본 또는 소성된 코크스로 예를 들 수 있다. 탄소계 화합물은 예를 들면, 인조 흑연, 천연 흑연 또는 흑연화 탄소 섬유와 같은 흑연 재료를 포함할 수 있고, 다른 분류로써 연화 탄소(soft carbon) 또는 경화 탄소(hard carbon)과 같은 저결정성 탄소; 및 무정형, 판상, 인편상, 구형 또는 섬유형의 천연 흑연 또는 인조 흑연, 키시흑연(Kish graphite), 열분해 탄소(pyrolytic carbon), 액정피치계 탄소섬유(mesophase pitch based carbon fiber), 탄소 미소구체(mesocarbon microbeads), 액정피치 (Mesophase pitches) 또는 석유와 석탄계 코크스(petroleum or coal tar pitch derived cokes)와 같은 고결정성 탄소로 이루어지는 군에서 선택된 하나 이상을 포함할 수 있다. 부가 음극 활물질은 알루미늄(Al), 주석(Sn), 납(Pb), 아연(Zn), 비스무트(Bi), 인듐(In), 마그네슘(Mg), 갈륨(Ga), 카드뮴(Cd) 및 실리콘(Si)으로 이루어지는 군에서 선택된 둘 이상의 원소를 포함하는 합금과 같은 금속 합금 화합물; 또는 바나듐 산화물 또는 리튬 바나듐 산화물과 같이 리튬을 도프(dope) 및 탈도프할 수 있는 금속 산화물(실리콘계 화합물 및 탄소계 화합물로 분류된 화합물은 제외함)로 이루어지는 군에서 선택된 하나 이상을 포함할 수 있다.In addition, when using a single cathode (200) without an individual cathode, the type of cathode active material included in the cathode active material layer (200b) can refer to the above-described content.

[0164] In condition iv), the main compound refers to the compound having the largest weight ratio among the compounds included in the negative electrode active material. The physical properties of the first negative electrode and the second negative electrode can be distinguished by varying the type of the main compound of the negative electrode active material included in each negative electrode active material layer. For example, the main compound of the negative electrode active material included in the first negative electrode active material layer may be a silicon-based compound, and the main compound of the negative electrode active material included in the second negative electrode active material layer may be a carbon-based compound.

[0165] In condition iv), even if the main compounds of the negative active material included in the first negative active material layer and the negative active material included in the second negative active material layer are the same, the physical properties can be distinguished by making the content ratios of these with respect to the total weight of the negative active materials different. For example, the negative active material included in the first negative active material layer may be a silicon-based compound at 40 wt% and a carbon-based compound at 60 wt%, and the negative active material included in the second negative active material layer may be a silicon-based compound at 10 wt% and a carbon-based compound at 90 wt%.

[0166] Although not particularly limited, for example, in condition iv), the negative active material included in the first negative active material layer and the negative active material included in the second negative active material layer may be different, and other conditions may be substantially the same. For example, one or more or all of the negative active material, the binder, and the conductive material included in each of the first negative active material layer and the second negative active material layer may have substantially the same content ratio. Here, the substantially same content ratio may mean that the absolute value of the difference in the content ratio of each component included in the first negative active material layer and the second negative active material layer may be 1% or less, 0.5% or less, or 0.1% or less. Here, the content ratio may mean the weight % of the content of the corresponding material relative to the total weight.

[0167] For example, in condition iv), the content ratio (W) of the negative electrode active material included in the first negative electrode active material layer NA1 ) and the content ratio of the negative electrode active material included in the second negative electrode active material layer (W NA2 ) difference (W NA1 -W NA2 ) may be 1% or less, 0.5% or less, or 0.1% or less. In addition, the content ratio (W) of the negative electrode binder included in the first negative electrode active material layer in condition iv) NB1 ) and the content ratio of the negative electrode binder included in the second negative electrode active material layer (W NB2 ) difference (W NB1 -W NB2 ) may be 1% or less, 0.5% or less, or 0.1% or less. In addition, in condition iv), the content ratio of the conductive material included in the 1 negative electrode active material layer (W PC1 ) and the content ratio of the conductive material included in the second negative electrode active material layer (W NC2 ) difference (W NC1 -W NC2 ) may be less than or equal to 1%, less than or equal to 0.5%, or less than or equal to 0.1%.

[0168] Although not particularly limited, for example, in condition iv), the negative active materials included in the first negative active material layer and the second negative active material layer may each independently be included in an amount of 80 wt% or more, 81 wt% or more, 82 wt% or more, 83 wt% or more, 84 wt% or more, 85 wt% or more, 86 wt% or more, 87 wt% or more, 88 wt% or more, 89 wt% or more, 90 wt% or more, 91 wt% or more, 92 wt% or more, 93 wt% or more, 94 wt% or more, 95 wt% or more, or 96 wt% or more, or 99 wt% or less or 98 wt% or less, based on the total weight. The content ratio of the negative active material may be within a range formed by appropriately selecting the above-mentioned upper and lower limits. When the content ratio of the negative active material satisfies the above range, it is possible to secure an appropriate energy capacity while generating excellent current output. In addition, when using a single negative electrode (200) without an individual negative electrode, the content of the negative electrode active material included in the negative electrode active material layer (200b) may refer to the aforementioned content. Hereinafter, when using a single negative electrode (200), the type and content of each component included in the negative electrode active material layer (200b) may be referred to.

[0169] Although not particularly limited, for example, in condition iv), the negative electrode binder included in the first negative electrode active material layer and the second negative electrode active material layer may be independently included in an amount of 0.01 parts by weight or more, 0.05 parts by weight or more, 0.1 parts by weight or more, 0.5 parts by weight or more, 1 part by weight or more, or 1.5 parts by weight or more, or 10 parts by weight or less, 9 parts by weight or less, 8 parts by weight or less, 7 parts by weight or less, 6 parts by weight or less, 5 parts by weight or less, 4 parts by weight or less, 3 parts by weight or less, or 2 parts by weight or less, based on 100 parts by weight of the negative electrode active material. The content ratio of the negative electrode binder may be within a range formed by appropriately selecting the above-mentioned upper and lower limits. When the content ratio of the negative electrode binder satisfies the above range, the internal bonding force of the negative electrode active material layer can be increased, the adhesive force with the negative electrode current collector can be improved, and stability can be secured.

[0170] In addition, for example, in condition iv), the negative electrode binder included in the first negative electrode active material layer and the second negative electrode active material layer is each independently selected from the group consisting of styrene butadiene rubber (SBR), polyvinylidene fluoride (PVDF), polyvinyl alcohol, polyethylene oxide, cyanoethylpullulan, cyanoethyl polyvinylalcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, polymethylmethacrylate, polybutylacrylate, polyacrylonitrile, polyvinylpyrrolidone, It may include at least one selected from the group consisting of polyvinylacetate, polyethylene-co-vinyl acetate, and polyarylate. Preferably, the negative electrode active material layer may include at least one selected from the group consisting of styrene butadiene rubber (SBR), polyvinylidene fluoride (PVDF), and polyvinyl alcohol as a negative electrode binder. However, the present invention is not limited thereto. In addition, it may be preferable that the negative electrode binders included in the first negative electrode active material layer and the second negative electrode active material layer each independently include styrene butadiene rubber (SBR).

[0171] In addition, when using a single cathode (200) without an individual cathode, the type and content of the cathode binder included in the cathode active material layer (200b) may refer to the above-mentioned content.

[0172] Although not particularly limited, for example, in condition iv), the first negative electrode active material layer and the second negative electrode active material layer may further include a thickener together with the negative electrode binder. The thickener included in the first negative electrode active material layer and the second negative electrode active material layer may be independently included in an amount of 0.01 parts by weight or more, 0.05 parts by weight or more, 0.1 parts by weight or more, 0.5 parts by weight or more, 1 part by weight or more, or 1.5 parts by weight or more, or 10 parts by weight or less, 9 parts by weight or less, 8 parts by weight or less, 7 parts by weight or less, 6 parts by weight or less, 5 parts by weight or less, 4 parts by weight or less, 3 parts by weight or less, or 2 parts by weight or less, based on 100 parts by weight of the negative electrode active material. Alternatively, the thickener included in the first negative electrode active material layer and the second negative electrode active material layer may be independently included in an amount of 50 parts by weight or more, 55 parts by weight or more, 60 parts by weight or more, 65 parts by weight or more, 70 parts by weight or more, 75 parts by weight or more, 80 parts by weight or more, 85 parts by weight or more, 90 parts by weight or more, 95 parts by weight or more, 100 parts by weight or more, or 200 parts by weight or less, 190 parts by weight or less, 180 parts by weight or less, 170 parts by weight or less, 160 parts by weight or less, 150 parts by weight or less, 140 parts by weight or less, 130 parts by weight or less, 120 parts by weight or less, or 110 parts by weight or less, based on 100 parts by weight of the negative electrode binder. The content ratio of the thickener may be within a range formed by appropriately selecting the above-mentioned upper and lower limits. When the content ratio of the thickener satisfies the above range, it can be combined with the negative electrode binder to increase the internal bonding force of the negative electrode active material layer and improve the adhesive force with the negative electrode current collector, thereby ensuring stability.

[0173] Although not particularly limited, for example, in condition iv), the conductive material included in the first negative electrode active material layer and the second negative electrode active material layer may be independently included in an amount of 0.1 part by weight or more, 0.5 part by weight or more, 1 part by weight or more, 2 parts by weight or more, 3 parts by weight or more, 4 parts by weight or more, or 5 parts by weight or more, or 20 parts by weight or less, 19 parts by weight or less, 18 parts by weight or less, 17 parts by weight or less, 16 parts by weight or less, 15 parts by weight or less, 14 parts by weight or less, 13 parts by weight or less, 12 parts by weight or less, 11 parts by weight or less, or 10 parts by weight or less, based on 100 parts by weight of the negative electrode active material. The content ratio of the conductive material may be within a range formed by appropriately selecting the above-mentioned upper and lower limits. When the content ratio of the conductive material satisfies the above range, better conductivity can be provided.

[0174] In addition, for example, the conductive materials included in the first negative electrode active material layer and the second negative electrode active material layer in condition iv) are not particularly limited as long as they are independently used in the art, and may include carbon-based conductive materials such as graphite, carbon black, acetylene black, Ketjen black, graphene, carbon nanotubes (CNTs), vapor-grown carbon fibers (VGCFs), and carbon fibers, and / or metal-based conductive materials including perovskite materials such as tin, tin oxide, titanium oxide, LaSrCoO3, and LaSrMnO3. The carbon nanotubes (CNTs) may include at least one selected from the group consisting of multi-walled carbon nanotubes (MWCNTs) and single-walled carbon nanotubes (SWCNTs) depending on the number of walls.

[0175] In addition, when using a single cathode (200) without an individual cathode, the type and content of the conductive material included in the cathode active material layer (200b) may refer to the above-described content.

[0176] In condition v), the content ratio of the conductive material included in the first negative electrode active material layer of the first negative electrode (W NC1 ) and the content ratio of the conductive material included in the second negative electrode active material layer of the second negative electrode (W NC2 ) difference (W NC1 -W NC2 ) may be 3 wt% or more, 3.2 wt% or more, 3.4 wt% or more, 3.6 wt% or more, 3.8 wt% or more, or 4 wt% or more, or 9.5 wt% or less, 9 wt% or less, 8 wt% or less, 7 wt% or less, 6 wt% or less, or 5 wt% or less. The difference in the content ratio of the conductive material (W NC1 -W NC2 ) can be within a range formed by appropriately selecting the upper and lower limits described above. That is, the physical properties of the first negative electrode and the second negative electrode can be distinguished by varying the content of the conductive material included in each negative electrode active material layer.

[0177] In condition v), the content ratio of the conductive material included in the first negative electrode active material layer of the first negative electrode (W NC1 ) and the content ratio of the conductive material included in the second negative electrode active material layer of the second negative electrode (W NC2 ) may be independently 10 wt% or less, 9.5 wt% or less, 9 wt% or less, 8.5 wt% or less, 8 wt% or less, 7.5 wt% or less, 7 wt% or less, 6.5 wt% or less, 6 wt% or less, 5.5 wt% or less, or 5 wt% or less, or 0.1 wt% or more, 0.5 wt% or more, or 1 wt% or more. The content ratio of the conductive material may be within a range formed by appropriately selecting the above-mentioned upper and lower limits. The type of the conductive material may refer to the content described in the above-mentioned condition iv).

[0178] In condition v), the negative active material included in the first negative active material layer of the first negative electrode and the negative active material included in the second negative active material layer of the second negative electrode may include the same material. Here, the same material may mean a compound of the same series. That is, even if the ratio of elements in the compound (e.g., molar ratio) is different, if it belongs to the same series when classified according to whether it is a silicon series, a carbon series, a metal alloy compound excluding these, or a metal oxide, it can be considered the same material.

[0179] In condition v), the content ratio (W) of the negative electrode active material included in the first negative electrode active material layer of the first negative electrode NA1 ) and the content ratio of the negative electrode active material contained in the second negative electrode active material layer of the second negative electrode (W NA2 ) difference (W NA1 -W NA2 ) may be 3 wt% or more, 3.5 wt% or more, 4 wt% or more, 4.5 wt% or more, 5 wt% or more, 5.5 wt% or more, 6 wt% or more, or may be 9.5 wt% or less, 9 wt% or less, 8.5 wt% or less, or 8 wt% or less, but is not particularly limited thereto. In condition v), the difference in the content ratio of the negative electrode active material (W NA1 -W NA2 ) can be within a range formed by appropriately selecting the upper and lower limits described above.

[0180] Although not particularly limited, for example, in condition v), the negative active materials included in the first negative active material layer and the second negative active material layer may each independently be included in an amount of 80 wt% or more, 81 wt% or more, 82 wt% or more, 83 wt% or more, 84 wt% or more, 85 wt% or more, 86 wt% or more, 87 wt% or more, 88 wt% or more, 89 wt% or more, 90 wt% or more, 91 wt% or more, 92 wt% or more, 93 wt% or more, 94 wt% or more, 95 wt% or more, or 96 wt% or more, or 99 wt% or less or 98 wt% or less, based on the total weight. The content ratio of the negative active material may be within a range formed by appropriately selecting the above-mentioned upper and lower limits. When the content ratio of the negative active material satisfies the above range, it is possible to secure an appropriate energy capacity while generating excellent current output.

[0181] Although not particularly limited, for example, in condition v), the negative electrode binder included in the first negative electrode active material layer and the second negative electrode active material layer may be independently included in an amount of 0.01 parts by weight or more, 0.05 parts by weight or more, 0.1 parts by weight or more, 0.5 parts by weight or more, 1 part by weight or more, or 1.5 parts by weight or more, or 10 parts by weight or less, 9 parts by weight or less, 8 parts by weight or less, 7 parts by weight or less, 6 parts by weight or less, 5 parts by weight or less, 4 parts by weight or less, 3 parts by weight or less, or 2 parts by weight or less, based on 100 parts by weight of the negative electrode active material. The content ratio of the negative electrode binder may be within a range formed by appropriately selecting the upper and lower limits described above. When the content ratio of the negative electrode binder satisfies the above range, the internal bonding force of the negative electrode active material layer can be increased and the adhesive force with the negative electrode current collector can be improved, thereby ensuring stability. The type of the negative electrode binder can refer to the contents described in condition iv) described above.

[0182] Meanwhile, the first cathode and the second cathode are CP when n is 100 in the following formula R R,ncan be distinguished. The second cathode has a CP when n is 100 in the following formula R compared to the first cathode. R,n This could be higher.

[0183] [Formula R]

[0184] CP R,n = CP n / CP1×100

[0185] In formula R, CP n represents the n-cycle discharge capacity, and CP1 represents the 1-cycle discharge capacity. The method of measuring the cycle discharge capacity can be referred to the above.

[0186] The second cathode has a CP when n is 100 in the following formula R compared to the first cathode R,n To achieve this higher level, the types or mixing ratios of the negative electrode active material included in the first negative electrode active material layer and the negative electrode active material included in the second positive electrode active material layer can be appropriately varied and selected. In addition, the content ratios of at least one of the negative electrode active material, negative electrode binder, and conductive material included in each of the first negative electrode active material layer and the second negative electrode active material layer can be appropriately varied and selected.

[0187] Number of first cathodes (N) n1 ) and the number of second cathodes (N n2 ) ratio (N) n1 / N n2 ) may be 10 or less, 9 or less, 8 or less, 7 or less, 6 or less, or 5 or less, or 0.1 or more, 0.5 or more, 1 or more, 2 or more, 3 or more, or 4 or more. The ratio of the number of the first cathode and the second cathode (N n1 / N n2 ) can be within a range formed by appropriately selecting the upper and lower limits described above. The ratio of the number of the first cathode and the second cathode (N n1 / N n2) If the above-mentioned range is satisfied, excellent capacity retention, high current output, and appropriate capacity can be secured by combining individual cathodes with distinct properties. Meanwhile, the number of first cathodes (N n1 ) and the number of second cathodes (N n2 ) can be measured by targeting the first cathode and the second cathode connected to the same cathode lead (420).

[0188] Number of first cathodes (N) n1 ) is the total number of cathodes (N nT ) may be 95% or less, 90% or less, 85% or less, 80% or less, 75% or less, 70% or less, 65% or less, 60% or less, 55% or less, or 50% or less, or 5% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, or 45% or more (excluding 100%) of the first cathode. The number of first cathodes (N n1 ) can be within the range formed by appropriately selecting the upper and lower limits mentioned above. The total number of cathodes (N nT ) means the total number of cathodes, including the first cathode and the second cathode, connected to the same cathode lead (420), and the number of first cathodes (N n1 ) means the number of first cathodes connected to the cathode lead (420).

[0189] Number of second cathodes (N) n2 ) is the total number of cathodes (N nT ) may be 95% or less, 90% or less, 85% or less, 80% or less, 75% or less, 70% or less, 65% or less, 60% or less, 55% or less, or 50% or less, or 5% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, or 45% or more (excluding 100%). The number of second cathodes (N n2 ) can be within the range formed by appropriately selecting the upper and lower limits mentioned above. The total number of cathodes (N nT) means the total number of cathodes, including the first cathode and the second cathode, connected to the same cathode lead (420), and the number of second cathodes (N n2 ) refers to the number of second cathodes connected to the cathode lead (420).

[0190] Total number of cathodes (N) nT ) Number of first cathodes (N) n1 ) and the number of second cathodes (N n2 ) is naturally affected by the number of the first cathode and the second cathode. For example, in a cathode (200) including only the first cathode and the second cathode, the first cathode is the number of the total cathodes (N nT ) is provided in a quantity of about 60% of the total number of cathodes (N). nT ) is prepared in a quantity of about 40% of the total.

[0191] The battery cell (10) may include a separator (300). The separator is not particularly limited as long as it is one used in the art, and it is preferable that it has low resistance to ion movement of the electrolyte and excellent wettability of the electrolyte (particularly, electrolyte solution). The separator may be, for example, a porous polymer film, for example, a porous polymer film made of a polyolefin material such as an ethylene polymer, a propylene polymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, or an ethylene / methacrylate copolymer, or a laminated structure of two or more layers thereof.

[0192] The battery cell (10) may include a case (500). In the battery cell (10), the electrode assembly may be housed in an internal space formed by the case (500). In addition, the battery cell (10) may include an electrolyte, and the electrolyte may be housed in the internal space formed by the case (500).

[0193] The case (500) may have various shapes, and depending on the shape, the battery cell (10) may be classified into a cylindrical shape, a square shape, a coin shape, a pouch shape, etc. The case (500) is not particularly limited, but may include aluminum (Al) to ensure rigidity, and when including aluminum, the built-in electrode assembly can be protected from external shock or vibration.

[0194] An electrolyte is a substance that enables the movement of electron transport substances between the anode (100) and cathode (200). The electrolyte may be liquid or solid at room temperature. If the electrolyte is liquid at room temperature, it can be called an electrolyte solution.

[0195] The electrolyte may include a lithium salt used in the art unless specifically limited. For example, in the lithium salt, the anion is F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - ,　 CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - and (CF3CF2SO2)2N- It may include one or more selected from the group consisting of. If necessary, the electrolyte may include a sodium salt, and the anion in the sodium salt may refer to the anion in the lithium salt described above. Hereinafter, the lithium salt will be described as a representative example.

[0196] The electrolyte may contain a lithium salt having a concentration of 0.1 M or more, 0.2 M or more, 0.3 M or more, 0.4 M or more, 0.5 M or more, 0.6 M or more, 0.7 M or more, 0.8 M or more, 0.9 M or more, or 1 M or more, or 10 M or less, 9 M or less, 8 M or less, 7 M or less, 6 M or less, 5 M or less, 4 M or less, 3 M or less, 2 M or less, or 1.5 M or less at 25°C. Here, M represents molar concentration (mol / L). The electrolyte may contain a lithium salt so as to have a concentration within a range formed by appropriately selecting the above-mentioned upper and lower limits.

[0197] The electrolyte may further comprise an organic solvent. The organic solvent may comprise at least one selected from the group consisting of carbonate solvents, ether solvents, and ester solvents. The electrolyte may further comprise an appropriate solvent considering appropriate viscosity and electrical conductivity.

[0198] The carbonate solvent may include at least one selected from the group consisting of cyclic carbonate solvents and linear carbonate solvents. The cyclic carbonate solvent may include, for example, at least one selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate (1,2-BC), 2,3-butylene carbonate (2,3-BC), 1,2-pentylene carbonate (1,2-PTC), 2,3-pentylene carbonate (2,3-PTC), and vinylene carbonate (VC). The linear carbonate solvent may include, for example, at least one selected from the group consisting of methyl carbonate, ethyl carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), ethylmethyl carbonate (EMC), methylpropyl carbonate (MPC), and ethylpropyl carbonate (EPC).

[0199] The ether solvent may include at least one selected from the group consisting of dimethyl ether, diethyl ether, dipropyl ether, methylethyl ether, methylpropyl ether, and ethylpropyl ether.

[0200] The ester solvent may include at least one selected from the group consisting of linear ester solvents and cyclic ester solvents. For example, the linear ester compound may include at least one selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, and butyl propionate. Furthermore, for example, the cyclic ester compound may include at least one selected from the group consisting of, for example, gamma-buturolactone, gamma-valerolactone, gamma-caprolactone, sigma-valerolactone, and epsilon-caprolactone.

[0201] The electrolyte may further include one or more selected from the group consisting of sulfite compounds, sulfone compounds, nitrile compounds, and borate compounds, as needed.

[0202] Meanwhile, if the electrolyte is solid at room temperature, a solid electrolyte layer containing the solid electrolyte can be interposed between the positive electrode (100) and the negative electrode (200) to simultaneously perform the function of a separator while transmitting an electron transfer material. In this case, the battery cell (10) can be referred to as an all-solid-state battery. The solid electrolyte can include, without limitation, those used in the art.

[0203] The battery cell (10) can be manufactured by a conventional method. In addition, the battery cell (10) can be manufactured by a conventional method including all of the above-described configurations.

[0204] A battery module or battery pack according to an example of the present application may include one or more battery cells (10). In addition, an electric device according to an example of the present application may include a battery cell (10), and the electric device is a device that operates through power generated from the battery cell (10), and may be, for example, a mobile phone, a home appliance, an electric vehicle, a hybrid vehicle, or an energy storage system (ESS).

[0205] The battery cell (10) can be widely applied to green technology fields such as electric vehicles, battery charging stations, and other battery-powered solar and wind power generation. Furthermore, the cell (10) according to an example of the present application can be applied to eco-friendly electric vehicles or hybrid vehicles, etc., to prevent climate change by suppressing air pollution and greenhouse gas emissions.

[0206]

[0207] [Method of measuring physical properties]

[0208] The properties mentioned below were measured as follows.

[0209] 1. Capacity retention evaluation

[0210] The manufactured battery cell was wrapped around the front and back of the battery cell with an aluminum (Al) plate jig, and the plate jig was fastened with bolts to fix the battery cell so that it does not move. Here, the battery cell was charged and discharged according to the current conditions as shown in Fig. 13 under the condition that 25℃ was maintained, and the discharge capacity was measured (1 cycle discharge capacity). Fig. 13 shows the current conditions that simulate the behavior of an electric vehicle or hybrid vehicle in a similar way to the actual one, and through this, the results can be derived closer to the actual one compared to measuring the capacity retention rate under the existing constant current / constant voltage (CC / CV) conditions. Fig. 13 shows an enlarged view of the dotted line area (continuous measurement time: 5,000 to 9,000 seconds). After that, charge and discharge were repeated n times (n>1, n is an integer) under the same current conditions, and the n cycle discharge capacity was measured. In addition, the capacity retention rate (CP), which is the ratio of the n cycle discharge capacity to the 1 cycle discharge capacity, was measured. R,n ) was measured using the following formula R and represented in a graph.

[0211] [Formula R]

[0212] CP R,n = CP n / CP1×100

[0213] In formula R, CP n represents the n-cycle discharge capacity, and CP1 represents the 1-cycle discharge capacity. The unit of the discharge capacity is mAh.

[0214] 2. Charge / discharge graph

[0215] The manufactured battery cell was charged and discharged under 0.5 C constant current / constant voltage (CC / CV) conditions in a voltage range of 2.5 V to 4.3 V at a temperature of 25°C, and a charge / discharge graph was presented.

[0216] Below, embodiments of the present application are further described with reference to specific examples. The embodiments and comparative examples are intended to exemplify the present application and do not limit the scope of the appended claims. It will be apparent to those skilled in the art that various modifications and variations of the embodiments are possible within the scope and technical spirit of the present application. Furthermore, it is also understood that such modifications and variations fall within the scope of the appended claims.

[0217] [Manufacturing example]

[0218] Manufacturing Example 1 - Manufacturing of the first anode

[0219] The first positive electrode was manufactured by applying an appropriate loading amount of a first positive electrode active material composition that forms a first positive electrode active material layer on both sides of aluminum foil, drying the aluminum foil on which the first positive electrode active material composition was applied at about 120° C. to form a first positive electrode active material layer, and rolling and cutting to form a first positive electrode tab.

[0220] The above first positive electrode active material composition was prepared by mixing a positive electrode active material (A), a positive electrode binder (B), and a conductive material (C) in a sufficient amount of solvent at a weight ratio of 96:2:2 (A:B:C).

[0221] The positive electrode active material (A) used lithium nickel-cobalt-manganese oxide (NCM) having a molar ratio of nickel (Ni): cobalt (Co): manganese (Mn) = 8:1:1. The positive electrode binder (B) used polyvinylidene fluoride (PVdF). The conductive material (C) used carbon black. In addition, the solvent used was N-methyl-2-pyrrolidone (NMP).

[0222] Manufacturing Example 2 - Manufacturing of the first anode

[0223] A first positive electrode was manufactured in the same manner as in Manufacturing Example 1, except that the first positive electrode active material composition was manufactured by mixing a positive electrode active material (A), a positive electrode binder (B), and a conductive material (C) in a sufficient amount of solvent at a weight ratio of 90:5:5 (A:B:C).

[0224] Manufacturing Example 3 - Manufacturing of the second anode

[0225] The second positive electrode was manufactured by applying a second positive electrode active material composition forming a second positive electrode active material layer on both sides of aluminum foil at an appropriate loading amount, drying the aluminum foil to which the second positive electrode active material composition was applied at about 120° C. to form a second positive electrode active material layer, and rolling and cutting to form a second positive electrode tab.

[0226] The above second positive electrode active material composition was prepared by mixing a positive electrode active material (A), a positive electrode binder (B), and a conductive material (C) in a sufficient amount of solvent at a weight ratio of 96:2:2 (A:B:C).

[0227] The positive electrode active material (A) used was lithium iron phosphate (LFP), and the positive electrode binder (B), conductive material (C), and solvent were the same as those used in Manufacturing Example 1.

[0228] Manufacturing Example 4 - Manufacturing of the second anode

[0229] The second positive electrode was manufactured by applying a second positive electrode active material composition forming a second positive electrode active material layer on both sides of aluminum foil at an appropriate loading amount, drying the aluminum foil to which the second positive electrode active material composition was applied at about 120° C. to form a second positive electrode active material layer, and rolling and cutting to form a second positive electrode tab.

[0230] The above second positive electrode active material composition was prepared by mixing a positive electrode active material (A), a positive electrode binder (B), and a conductive material (C) in a sufficient amount of solvent at a weight ratio of 98:1:1 (A:B:C).

[0231] The positive electrode active material (A) used was lithium nickel-cobalt-manganese oxide (NCM) having a molar ratio of nickel (Ni): cobalt (Co): manganese (Mn) = 8:1:1. The positive electrode binder (B), conductive material (C), and solvent were the same as those used in Manufacturing Example 1.

[0232] Manufacturing Example 5 - Manufacturing of the second anode

[0233] A second positive electrode was manufactured in the same manner as in Manufacturing Example 4, except that the second positive electrode active material composition was manufactured by mixing the second positive electrode active material (A), the first positive electrode binder (B), and the conductive material (C) in a sufficient amount of solvent at a weight ratio of 96:2:2 (A:B:C).

[0234] Manufacturing Example 6 - Manufacturing of the cathode

[0235] The negative electrode was manufactured by applying an appropriate loading amount of a negative electrode active material composition that forms a negative electrode active material layer on both sides of a copper foil, drying the copper foil on which the negative electrode active material composition was applied at about 80° C. to form a negative electrode active material layer, and rolling and cutting to form a negative electrode tab.

[0236] The above negative active material composition was prepared by mixing artificial graphite (A), negative electrode binder (B), conductive agent (C), and thickener (D) in a weight ratio of 95:1.5:2:1.5 (A:B:C:D) in a sufficient amount of deionized water.

[0237] The above negative electrode binder (B) used styrene-butadiene rubber. The above conductive material (C) used carbon black. The above thickener (D) used carboxymethyl cellulose.

[0238] Manufacturing Example 7 - Manufacturing of the first cathode

[0239] The first negative electrode was manufactured by applying an appropriate loading amount of a first negative electrode active material composition that forms a first negative electrode active material layer on both sides of a copper foil, drying the copper foil on which the first negative electrode active material composition was applied at about 80° C. to form a first negative electrode active material layer, and rolling and cutting to form a first negative electrode tab.

[0240] The above first negative electrode active material composition was prepared by mixing artificial graphite (A), negative electrode binder (B), conductive agent (C), and thickener (D) in a weight ratio of 92:1.5:5:1.5 (A:B:C:D) in a sufficient amount of deionized water.

[0241] The above negative electrode binder (B) used styrene-butadiene rubber. The above conductive material (C) used carbon black. The above thickener (D) used carboxymethyl cellulose.

[0242] Manufacturing Example 8 - Manufacturing of the second cathode

[0243] The second negative electrode was manufactured by applying a second negative electrode active material composition forming a second negative electrode active material layer on both sides of a copper foil at an appropriate loading amount, drying the copper foil on which the second negative electrode active material composition was applied at about 80° C. to form a second negative electrode active material layer, and rolling and cutting to form a second negative electrode tab.

[0244] The above second negative electrode active material composition was prepared by mixing artificial graphite (A), negative electrode binder (B), conductive agent (C), and thickener (D) in a weight ratio of 98:0.5:1:0.5 (A:B:C:D) in a sufficient amount of deionized water.

[0245] The above negative electrode binder (B) used styrene-butadiene rubber. The above conductive material (C) used carbon black. The above thickener (D) used carboxymethyl cellulose.

[0246] Manufacturing Example 9 - Manufacturing of a cathode

[0247] A negative electrode was manufactured in the same manner as in Manufacturing Example 6, except that the negative electrode active material composition was manufactured by mixing artificial graphite (A), negative electrode binder (B), conductive agent (C), and thickener (D) in a sufficient amount of deionized water at a ratio of 94:1.5:3:1.5 (A:B:C:D).

[0248] [Example]

[0249] Example 1.

[0250] An electrode assembly was manufactured by interposing a polyolefin separator (thickness: 15 ㎛, porosity: 40%) between the first positive electrode manufactured in Manufacturing Example 1 or the second positive electrode manufactured in Manufacturing Example 3 and the negative electrode manufactured in Manufacturing Example 6. Meanwhile, the second positive electrode manufactured in Manufacturing Example 3 had a CP according to Formula R compared to the first positive electrode manufactured in Manufacturing Example 1. R,100 This had a larger value. In addition, the first positive tab of the first positive electrode and the second positive tab of the second positive electrode were welded to the same positive electrode lead to be fixed and electrically connected, and the negative tab of the negative electrode was welded to the negative electrode lead to be fixed and electrically connected. The electrode assembly with the electrode leads connected was placed in a pouch case, and an electrolyte was injected into the pouch case and then sealed to manufacture a pouch-type battery cell.

[0251] Here, the ratio of the number of the first anode (N1) and the number of the second anode (N2) is set to 1:3 (N1:N2), and the number of the first anode (N1) is the total number of anodes (N T) was about 25% of the total number of anodes (N2), and the number of the second anodes (N2) was about 25% of the total number of anodes (N T ) was about 75% of the original.

[0252] Specifically, the manufactured electrode assembly includes a structure in which the first anode-cathode-second anode-cathode-second anode-cathode-second anode are stacked in that order, and a separator is interposed between the first anode and the cathode and the second anode and the cathode.

[0253] In addition, the electrolyte was prepared to be liquid at room temperature, and was prepared by dissolving LiPF6, a lithium salt, in an organic solvent containing ethylene carbonate (EC) and ethylmethyl carbonate (EMC) mixed in a volume ratio of 25:75 (EC:EMC) to have a concentration of 1.0 M (based on 25°C).

[0254] Example 2.

[0255] The ratio of the number of the first anode (N1) and the number of the second anode (N2) was set to 2:2 (N1:N2), and the number of the first anode (N1) was set to the total number of anodes (N T ) was about 50% of the total number of anodes (N2), and the number of the second anodes (N2) was about 50% of the total number of anodes (N T ) A battery cell was manufactured in the same manner as in Example 1, except that the electrode assembly was manufactured at approximately 50% of the original weight.

[0256] In addition, the specifically manufactured electrode assembly includes a structure (so-called zigzag structure) in which the first anode-cathode-second anode-cathode-first anode-cathode-second anode are stacked in that order, and a separator is interposed between the first anode and the cathode and the second anode and the cathode.

[0257] Example 3.

[0258] The ratio of the number of the first anode (N1) and the number of the second anode (N2) was set to 3:1 (N1:N2), and the number of the first anode (N1) was set to the total number of anodes (N T) was about 75% of the total number of anodes (N2), and the number of the second anodes (N2) was about 75% of the total number of anodes (N T ) A battery cell was manufactured in the same manner as in Example 1, except that the electrode assembly was manufactured at a ratio of about 25%.

[0259] In addition, the specifically manufactured electrode assembly includes a structure in which the first anode-cathode-first anode-cathode-first anode-cathode-second anode is laminated in that order, and a separator is interposed between the first anode and the cathode and the second anode and the cathode.

[0260] Comparative Example 1.

[0261] An electrode assembly was manufactured by interposing a polyolefin separator (thickness: 20 ㎛, porosity: 40%) between the first positive electrode manufactured in Manufacturing Example 1 and the negative electrode manufactured in Manufacturing Example 6. In addition, the first positive electrode tab of the first positive electrode was welded to the positive electrode lead to be fixed and electrically connected, and the negative electrode tab of the negative electrode was welded to the negative electrode lead to be fixed and electrically connected. The electrode assembly with the electrode leads connected was placed in a pouch case, and an electrolyte was injected into the pouch case and then sealed to manufacture a pouch-type battery cell. The total number of positive electrodes (N) T ) was the same as in Example 1. In addition, the same electrolyte as that used in Example 1 was used.

[0262] Comparative Example 2.

[0263] An electrode assembly was manufactured by interposing a polyolefin separator (thickness: 20 ㎛, porosity: 40%) between the second positive electrode manufactured in Manufacturing Example 3 and the negative electrode manufactured in Manufacturing Example 6. In addition, the second positive electrode tab of the second positive electrode was welded to the positive electrode lead to be fixed and electrically connected, and the negative electrode tab of the negative electrode was welded to the negative electrode lead to be fixed and electrically connected. The electrode assembly with the electrode leads connected was placed in a pouch case, and an electrolyte was injected into the pouch case and then sealed to manufacture a pouch-type battery cell. The total number of positive electrodes (N) T ) was the same as in Example 1. In addition, the same electrolyte as that used in Example 1 was used.

[0264]

[0265] Example 4.

[0266] An electrode assembly was manufactured by interposing a polyolefin separator (thickness: 20 ㎛, porosity: 40%) between the first positive electrode manufactured in Manufacturing Example 2 or the second positive electrode manufactured in Manufacturing Example 4 and the negative electrode manufactured in Manufacturing Example 6. Meanwhile, the second positive electrode manufactured in Manufacturing Example 4 had a CP according to Formula R compared to the first positive electrode manufactured in Manufacturing Example 2. R,100 This had a larger value. In addition, the first positive tab of the first positive electrode and the second positive tab of the second positive electrode were welded to the same positive electrode lead to be fixed and electrically connected, and the negative tab of the negative electrode was welded to the negative electrode lead to be fixed and electrically connected. The electrode assembly with the electrode leads connected was placed in a pouch case, and an electrolyte was injected into the pouch case and then sealed to manufacture a pouch-type battery cell.

[0267] Here, the ratio of the number of the first anode (N1) and the number of the second anode (N2) is set to 2:2 (N1:N2), and the number of the first anode (N1) is the total number of anodes (N T ) was about 50% of the total number of anodes (N2), and the number of the second anodes (N2) was about 50% of the total number of anodes (NT ) was about 50% of the original.

[0268] Specifically, the manufactured electrode assembly includes a structure (so-called zigzag structure) in which the first anode-cathode-second anode-cathode-first anode-cathode-second anode are stacked in that order, and a separator is interposed between the first anode and the cathode and the second anode and the cathode.

[0269] In addition, the electrolyte was prepared to be liquid at room temperature, and was prepared by dissolving LiPF6, a lithium salt, in an organic solvent containing ethylene carbonate (EC) and ethylmethyl carbonate (EMC) mixed in a volume ratio of 25:75 (EC:EMC) to have a concentration of 1.0 M (based on 25°C).

[0270] Example 5.

[0271] The ratio of the number of the first anode (N1) and the number of the second anode (N2) was set to 3:1 (N1:N2), and the number of the first anode (N1) was set to the total number of anodes (N T ) was about 75% of the total number of anodes (N2), and the number of the second anodes (N2) was about 75% of the total number of anodes (N T ) A battery cell was manufactured in the same manner as in Example 4, except that the electrode assembly was manufactured at a ratio of about 25%.

[0272] In addition, the specifically manufactured electrode assembly includes a structure in which the first anode-cathode-first anode-cathode-first anode-cathode-second anode is laminated in that order, and a separator is interposed between the first anode and the cathode and the second anode and the cathode.

[0273] Comparative Example 3.

[0274] An electrode assembly was manufactured by interposing a polyolefin separator (thickness: 20 ㎛, porosity: 40%) between the second positive electrode manufactured in Manufacturing Example 5 and the negative electrode manufactured in Manufacturing Example 6. In addition, the second positive electrode tab of the second positive electrode was welded to the positive electrode lead to be fixed and electrically connected, and the negative electrode tab of the negative electrode was welded to the negative electrode lead to be fixed and electrically connected. The electrode assembly with the electrode leads connected was placed in a pouch case, and an electrolyte was injected into the pouch case and then sealed to manufacture a pouch-type battery cell. The total number of positive electrodes (N) T ) was the same as in Example 4. In addition, the same electrolyte as that used in Example 4 was used.

[0275]

[0276] Example 6.

[0277] An electrode assembly was manufactured by interposing a polyolefin separator (thickness: 15 ㎛, porosity: 40%) between the (first) positive electrode manufactured in Manufacturing Example 1 and the first negative electrode manufactured in Manufacturing Example 7 or the second negative electrode manufactured in Manufacturing Example 8. Meanwhile, the second negative electrode manufactured in Manufacturing Example 8 had a CP according to the formula R compared to the first negative electrode manufactured in Manufacturing Example 7. R,100 This had a larger value. In addition, the first negative tab of the first negative electrode and the second negative tab of the second negative electrode were welded to the same negative electrode lead to be fixed and electrically connected, and the (first) positive tab of the positive electrode was welded to the positive electrode lead to be fixed and electrically connected. The electrode assembly with the electrode leads connected was placed in a pouch case, and an electrolyte was injected into the pouch case and then sealed to manufacture a pouch-type battery cell.

[0278] Here, the number of the first cathode (N n1 ) and the number of second cathodes (N n2 ) is a ratio of 2:2(N n1 :N n2 ) and the number of the first cathode (N) n1) is the total number of cathodes (N nT ) was about 50% of the number of the second cathode (N n2 ) is the total number of cathodes (N nT ) was about 50% of the original.

[0279] Specifically, the manufactured electrode assembly includes a structure (so-called zigzag structure) in which the first cathode-anode-second cathode-anode-first cathode-anode-second cathode are stacked in the order manufactured in Manufacturing Example 7, and a separator is interposed between the first cathode and the anode and the second cathode and the anode.

[0280] In addition, the electrolyte was prepared to be liquid at room temperature, and was prepared by dissolving LiPF6, a lithium salt, in an organic solvent containing ethylene carbonate (EC) and ethylmethyl carbonate (EMC) mixed in a volume ratio of 25:75 (EC:EMC) to have a concentration of 1.0 M (based on 25°C).

[0281] Comparative Example 4.

[0282] An electrode assembly was manufactured by interposing a polyolefin separator (thickness: 20 ㎛, porosity: 40%) between the (first) positive electrode manufactured in Manufacturing Example 1 and the negative electrode manufactured in Manufacturing Example 9. In addition, the (first) positive electrode tab of the positive electrode was welded to the positive electrode lead to be fixed and electrically connected, and the negative electrode tab of the negative electrode was welded to the negative electrode lead to be fixed and electrically connected. The electrode assembly with the electrode leads connected was placed in a pouch case, an electrolyte was injected into the pouch case, and then sealed to manufacture a pouch-type battery cell. The total number of negative electrodes (N) nT ) was the same as in Example 6. In addition, the same electrolyte as that used in Example 6 was used.

[0283]

[0284] The results of tests performed based on the battery cells manufactured in Examples 1 to 3, Comparative Examples 1 and 2 are shown in FIGS. 7 and 8, and the results of tests performed based on the battery cells manufactured in Examples 4, 5, Comparative Examples 3 and 4 are shown in FIGS. 9 and 10.

[0285] Referring to FIG. 7, it can be seen that Examples 1 to 3 exhibit excellent capacity retention, while Comparative Example 1 exhibits low capacity retention. In addition, referring to FIG. 8, it can be seen that Examples 1 to 3 exhibit excellent output and have appropriate capacity, while Comparative Example 2 has high resistance, a large voltage drop, low current output, and relatively low capacity.

[0286] Referring to Fig. 9, it can be seen that Examples 4 and 5 exhibit relatively excellent capacity retention rates. In addition, referring to Fig. 10, it can be seen that Examples 4 and 5 exhibit excellent output and have relatively large capacities, while Comparative Example 3 has relatively low capacities.

[0287] Referring to Fig. 11, it can be seen that Example 6 exhibits a relatively excellent capacity retention rate. In addition, referring to Fig. 12, it can be seen that Example 6 exhibits excellent output and has a relatively large capacity, while Comparative Example 4 has a relatively low capacity.

[0288]

[0289] While various embodiments of the present application have been described in detail above, the scope of the present application is not limited thereto. Furthermore, it will be apparent to those skilled in the art that various modifications and variations are possible without departing from the technical spirit of the present application as defined in the claims. Furthermore, some components of the above-described embodiments may be omitted, and the embodiments may be combined with each other.

[0290] [Explanation of symbols]

[0291] 10... battery cell 100... positive electrode

[0292] 110... 1st positive electrode 110a... 1st positive electrode tap

[0293] 110b... First positive electrode active material layer 110c... First positive electrode non-conductive layer

[0294] 120... Second anode 120a... Second anode tap

[0295] 120b... Second positive electrode active material layer 120c... Second positive electrode non-conductive layer

[0296] 200... negative 200a... negative tab

[0297] 200b... negative electrode active material layer 200c... negative electrode non-conductive layer

[0298] 300... separator 400... electrode lead

[0299] 410... positive lead 420... negative lead

[0300] 500... case 600... terminal

[0301] 610... positive terminal 620... negative terminal

Claims

1. Comprising a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, The above anode includes a first anode and a second anode, The first positive electrode includes a first positive electrode active material layer, and the second positive electrode includes a second positive electrode active material layer, The first positive electrode active material layer and the second positive electrode active material layer each include a positive electrode active material, a positive electrode binder, and a conductive material, A battery cell wherein the first positive electrode and the second positive electrode satisfy at least one of the following conditions: [condition] Condition i) The positive electrode active material included in the first positive electrode active material layer and the positive electrode active material included in the second positive electrode active material layer are different materials, or Condition ii) The content ratio of at least one of the positive electrode active material, positive electrode binder and conductive material included in the first positive electrode active material layer and the second positive electrode active material layer is different, or Condition iii) The loading amount (LW1) of the first positive electrode active material composition forming the first positive electrode active material layer and the loading amount (LW2) of the second positive electrode active material composition forming the second positive electrode active material layer are different.

2. In paragraph 1, The first anode comprises a first anode tab, and the second anode comprises a second anode tab, A battery cell wherein the first positive tab and the second positive tab are connected to the same positive lead.

3. In paragraph 1, The above second anode has a CP when n is 100 in the following formula R compared to the first anode. R,n This is higher, A battery cell wherein the ratio (N1 / N2) of the number of the first positive electrode (N1) and the number of the second positive electrode (N2) is 10 or less: [Formula R] CP R,n = CP n / CP1×100 In formula R, CP n CP1 represents the n-cycle discharge capacity, and CP2 represents the 1-cycle discharge capacity.

4. In paragraph 3, The number of the first anode (N1) above is the total number of anodes (N T ) is less than 95% compared to the number of the second anode (N2), and the number of the total anodes (N T ) Battery cells with a capacity of 5% or more (excluding 100%).

5. In paragraph 1, The above cathode includes a first cathode and a second cathode, The first negative electrode comprises a first negative electrode active material layer, and the second negative electrode comprises a second negative electrode active material layer. The first negative electrode active material layer and the second negative electrode active material layer each include a negative electrode active material, a negative electrode binder, and a conductive material, The above first cathode and second cathode are battery cells satisfying the following conditions: [condition] Condition iv) The main compound of the negative active material included in the first negative active material layer and the main compound of the negative active material included in the second negative active material layer have at least one different component element or a different content ratio, Condition v) The content ratio of at least one of the negative electrode active material, negative electrode binder and conductive material included in the first negative electrode active material layer and the second negative electrode active material layer is different, or Condition vi) The loading amount (LW3) of the first negative electrode active material composition forming the first negative electrode active material layer and the loading amount (LW4) of the second negative electrode active material composition forming the second negative electrode active material layer are different.

6. In paragraph 5, The first cathode includes a first cathode tab, and the second cathode includes a second cathode tab, A battery cell wherein the first negative tab and the second negative tab are connected to the same negative lead.

7. In paragraph 1, A battery cell in which, in condition i), the positive electrode active material included in the first positive electrode active material layer and the positive electrode active material included in the second positive electrode active material layer are materials in which at least one or more constituent elements are different, or even if expressed by the same chemical formula, the composition ratios of the elements constituting the chemical formula are different.

8. In paragraph 1, In condition i), the positive electrode active material included in the first positive electrode active material layer and the positive electrode active material included in the second positive electrode active material layer may each independently include at least one compound selected from the group consisting of a compound represented by the following chemical formula P1, a compound represented by the following chemical formula P2, and a compound represented by the following chemical formula P3, The positive electrode active material included in the first positive electrode active material layer and the positive electrode active material included in the second positive electrode active material layer are a battery cell in which at least one element selected from the group consisting of A, M1, M2 and M3 in the following chemical formulas P1, P2 and P3 is different, or at least one numerical value selected from the group consisting of a, x, y and z is different: [Chemical formula P1] A a M 1x M 2y M 3z O2 [Chemical formula P2] A a M 1x M 2y M 3z (PO4) [Chemical formula P3] From a M 1x M 2y M 3z (CN)6 In the chemical formula P1, chemical formula P2 and chemical formula P3 above, A is lithium (Li), sodium (Na) or potassium (K), M1, M2 and M3 are at least one selected from the group consisting of nickel (Ni), cobalt (Co), manganese (Mn), iron (Fe), chromium (Cr), vanadium (V), niobium (Nb), boron (B), aluminum (Al), copper (Cu), zirconium (Zr), tungsten (W), titanium (Ti), zinc (Zn), gallium (Ga), germanium (Ge), molybdenum (Mo), tantalum (Ta), yttrium (Y), barium (Ba) and hafnium (Hf) so as not to overlap each other, x, y and z are each independently 0 or more and 1 or less, and satisfy x+y+z=1, a in the chemical formula P1 is 0.5 or more and 1.8 or less, and a in the chemical formula P2 is 0.8 or more and 1.2 Below, in chemical formula P3, a is 0.8 or more and 2.2 or less.

9. In paragraph 1, In condition i), the content ratio (W) of the positive electrode active material included in the first positive electrode active material layer PA1 ) and the content ratio of the positive electrode active material contained in the second positive electrode active material layer (W PA2 ) difference (W PA1 -W PA2 ) is a battery cell having an absolute value of 1 wt% or less.

10. In paragraph 1, In condition ii), the content ratio (W) of the conductive material included in the first positive electrode active material layer PC1 ) is the content ratio of the conductive material included in the second positive electrode active material layer (W PC2 ) larger battery cells.

11. In Article 10, In condition ii), the content ratio (W) of the conductive material included in the first positive electrode active material layer PC1 ) and the content ratio of the conductive material included in the second positive electrode active material layer (W PC2 ) difference (W PC1 -W PC2 ) is a battery cell having 3 wt% or more.

12. In paragraph 10, In condition ii), the content ratio (W) of the conductive material included in the first positive electrode active material layer PC1 ) and the content ratio of the conductive material included in the second positive electrode active material layer (W PC2 ) are battery cells each independently of the other, each of which is less than 10 wt%.

13. In paragraph 10, In condition ii), a battery cell wherein the positive electrode active material included in the first positive electrode active material layer and the positive electrode active material included in the second positive electrode active material layer include the same material.

14. In paragraph 13, In condition ii), the content ratio (W) of the positive electrode active material included in the first positive electrode active material layer PA1 ) and the content ratio of the positive electrode active material contained in the second positive electrode active material layer (W PA2 ) difference (W PA1 -W PA2 ) is a battery cell having an absolute value of 3 wt% or more.

15. In paragraph 13, In condition ii), the content ratio (W) of the positive electrode active material included in the first positive electrode active material layer PA1 ) and the content ratio of the positive electrode active material contained in the second positive electrode active material layer (W PA2 ) are battery cells each independently having 80 wt% or more.

16. Including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, The above cathode includes a first cathode and a second cathode, The first negative electrode comprises a first negative electrode active material layer, and the second negative electrode comprises a second negative electrode active material layer. The first negative electrode active material layer and the second negative electrode active material layer each include a negative electrode active material, a negative electrode binder, and a conductive material, A battery cell wherein the first cathode and the second cathode satisfy at least one of the following conditions: [condition] Condition iv) The main compound of the negative active material included in the first negative active material layer and the main compound of the negative active material included in the second negative active material layer have at least one different component or a different content ratio, Condition v) The content ratio of at least one of the negative electrode active material, negative electrode binder and conductive material included in the first negative electrode active material layer and the second negative electrode active material layer is different, or Condition vi) The loading amount (LW3) of the first negative electrode active material composition forming the first negative electrode active material layer and the loading amount (LW4) of the second negative electrode active material composition forming the second negative electrode active material layer are different.

17. In paragraph 16, In condition v), the content ratio (W) of the conductive material included in the first negative electrode active material layer NC1 ) and the content ratio of the conductive material included in the second negative electrode active material layer (W NC2 ) difference (W NC1 -W NC2 ) is a battery cell having 3 wt% or more.

18. In paragraph 16, In condition v), the content ratio (W) of the negative electrode active material included in the first negative electrode active material layer NA1 ) and the content ratio of the negative electrode active material included in the second negative electrode active material layer (W NA2 ) difference (W NA1 -W NA2 ) is a battery cell having an absolute value of 3 wt% or more.

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