Battery Pack

Abstract

A battery pack is provided. The battery pack includes: a battery cell including an electrode extending in a first direction; a circuit portion connected to the electrode of the battery cell; and a connection portion forming a connection between the electrode of the battery cell and the circuit portion, the connection portion including a conductive thermocompression bonding layer and a conductive pad layer, the conductive pad layer having a concave accommodation space formed in a second direction intersecting the first direction to accommodate a portion of the conductive thermocompression bonding layer. According to the disclosure, a battery pack can be provided that can easily perform a connection process and simultaneously increase the reliability of the electrical connection between the battery cell and the circuit portion forming a charge and discharge path of the battery cell.

Description

[0001] This application is based on and claims the benefit of priority from Korean Patent Application No. 10-2021-0034239 filed in the Korean Intellectual Property Office on March 16, 2021, the disclosure of which is incorporated herein in its entirety by reference. Technical Field

[0002] One or more embodiments relate to a battery pack. Background Art

[0003] Generally, unlike a primary battery that cannot be charged, a secondary battery is a battery that can be charged and discharged. Secondary batteries are used as energy sources for mobile devices, electric vehicles, hybrid vehicles, electric bicycles, uninterruptible power supplies, etc. Depending on the type of external device to be applied, the secondary battery can be used in the form of a single battery or in the form of a module bundled into one unit by connecting a plurality of batteries. Summary of the invention

[0004] One or more embodiments include a battery pack that can easily perform a connection process and simultaneously increase reliability of electrical connection between a battery cell and a circuit part forming a charge and discharge path of the battery cell.

[0005] Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the disclosed embodiments.

[0006] According to one or more embodiments, a battery pack includes: a battery cell including an electrode extending in a first direction; a circuit portion connected to the electrode of the battery cell; and a connecting portion forming a connection between the electrode of the battery cell and the circuit portion, the connecting portion including a conductive hot compression bonding layer and a conductive pad layer, the conductive pad layer having a concave accommodating space formed in a second direction intersecting the first direction to accommodate a portion of the conductive hot compression bonding layer.

[0007] The electrode may include a first electrode and a second electrode arranged in a third direction intersecting the first direction and the second direction, the first electrode and the second electrode having different polarities, wherein the conductive pad may include a first conductive pad and a second conductive pad, the first conductive pad and the second conductive pad are separated from each other in the third direction to be connected to the first electrode and the second electrode, respectively.

[0008] The conductive thermocompression bonding layer may be continuously formed between the first electrode and the first conductive pad layer and between the second electrode and the second conductive pad layer along the third direction.

[0009] The conductive thermocompression bonding layer may be located between the electrode of the battery cell and the conductive pad layer in the second direction.

[0010] The conductive pad layer may include a convex portion relatively protruding in the second direction and a concave portion relatively concave in the second direction.

[0011] The recess may provide a concave receiving space.

[0012] The conductive thermocompression bonding layer may include conductive particles supported on the convex portions and an insulating resin accommodated in the concave portions.

[0013] The convex portion and the concave portion may extend in parallel in the first direction.

[0014] The convex portion and the concave portion include the same metal material.

[0015] The conductive pad layer may include an uneven pattern in which convex portions and concave portions are alternately arranged in a third direction intersecting the first direction and the second direction.

[0016] The uneven pattern may be formed at a position offset close to a front position of the conductive pad layer facing the battery cell.

[0017] The uneven pattern may be completely surrounded by the edge portion of the conductive pad layer.

[0018] An insulating layer may be formed around the conductive pad layer.

[0019] At least some of edge portions of the conductive pad layer forming a boundary between the conductive pad layer and the insulating layer may form a step so that an upper surface of the conductive pad layer significantly protrudes than an upper surface of the insulating layer in the second direction.

[0020] A step may be formed around an uneven pattern formed on the conductive pad layer.

[0021] A step may be formed around the conductive thermo-compression bonding layer.

[0022] The edge portion of the conductive pad layer may include: a front edge portion formed at a position relatively close to the battery cell along the first direction; a rear edge portion formed at a position relatively far from the battery cell along the first direction; and a side edge portion connecting the front edge portion to the rear edge portion.

[0023] The step may be formed in a front portion of the side edge portion overlapping the uneven pattern in a third direction intersecting the first direction and the second direction.

[0024] The step may be formed in a front portion of the side edge portion overlapping the conductive thermo-compression bonding layer in a third direction intersecting the first direction and the second direction.

[0025] The step may be formed in a front edge portion relatively close to the battery cell in the first direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and other aspects, features and advantages of some disclosed embodiments will become more apparent through the following description in conjunction with the accompanying drawings, in which:

[0027] Figure 1 is a perspective view of a battery pack according to a disclosed embodiment;

[0028] Figure 2 yes Figure 1 An exploded perspective view of a battery pack shown in ;

[0029] Figure 3 yes Figure 1 A perspective view of a portion of a battery pack shown in ;

[0030] Figure 4 It is along Figure 3 A sectional view taken along line IV-IV of ;

[0031] Figure 5 yes Figure 1 A perspective view of a portion of a battery pack shown in ;

[0032] Figure 6 yes Figure 5 A plan view of a portion of a battery pack shown in ;

[0033] Figure 7 yes Figure 1 a perspective view of a portion of a battery pack shown in; and

[0034] Fig. 8A The structure of a comparative example for measuring the connection resistance value between the electrode and the conductive pad layer of a battery cell is shown, and Figure 8B The structure of the disclosed embodiment for measuring the connection resistance value between the electrode of the battery cell and the conductive pad layer is shown as an experiment for demonstrating the technical effect of the disclosed embodiment. DETAILED DESCRIPTION

[0035] The embodiments illustrated in the accompanying drawings will now be referred to in detail, wherein the same reference numerals represent the same elements throughout. In this regard, the current embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Therefore, the embodiments are described below only by reference to the accompanying drawings to explain aspects of this specification. As used herein, the term "and / or (and / or)" includes any combination and all combinations of one or more of the related listed items. When a statement such as "at least one (kind / person) of ... " is after a column of elements, the entire column of elements is modified without modifying the individual elements listed.

[0036] Hereinafter, a battery pack according to a disclosed embodiment will be described with reference to the accompanying drawings.

[0037] Figure 1 is a perspective view of a battery pack according to a disclosed embodiment. Figure 2 yes Figure 1 An exploded perspective view of the battery pack shown in FIG. Figure 3 yes Figure 1 A perspective view of a portion of a battery pack is shown in FIG. Figure 4 It is along Figure 3 A cross-sectional view taken along line IV-IV. Figure 5 yes Figure 1 A perspective view of a portion of a battery pack is shown in FIG. Figure 6 yes Figure 5 A plan view of a portion of a battery pack is shown in FIG. Figure 7 yes Figure 1 A perspective view of a portion of a battery pack is shown in FIG.

[0038] Reference Figure 1 and Figure 2 According to the disclosed embodiment, the battery pack may include: a battery cell 10, including electrodes 11 and 12 extending in a first direction Z1; a circuit portion C, connected to the electrodes 11 and 12 of the battery cell 10; and a connecting portion 56, for forming a connection between the electrodes 11 and 12 of the battery cell 10 and the circuit portion C, the connecting portion 56 including a conductive hot-pressing bonding layer 50 and a conductive pad layer 60, the conductive pad layer 60 having a concave accommodating space formed in a second direction Z2 intersecting the first direction Z1 to accommodate a portion of the conductive hot-pressing bonding layer 50.

[0039] The battery cell 10 may include an electrode assembly 10a, a shell 10b surrounding the electrode assembly 10a, and electrodes 11 and 12 led out from the shell 10b. Although not shown in the drawings, the electrode assembly 10a may be formed in a winding type, wherein the first electrode plate and the second electrode plate and the separator between the first electrode plate and the second electrode plate are wound in a roll. Alternatively, the electrode assembly 10a may be formed in a stacked type, wherein the first electrode plate and the second electrode plate and the separator are stacked on each other. The first electrode plate and the second electrode plate of the electrode assembly 10a may be electrically connected to the outside of the shell 10b through the electrodes 11 and 12 of the battery cell 10. The electrodes 11 and 12 of the battery cell 10 may be electrically connected to the first electrode plate and the second electrode plate of the electrode assembly 10a, respectively, and may include a first electrode 11 and a second electrode 12 having different polarities.

[0040] The shell 10b may be formed to surround the electrode assembly 10a, and a sealing portion TS for sealing the electrode assembly 10a may be formed by sealing the excess portion of the shell 10b remaining after surrounding the electrode assembly 10a. In this case, the battery cell 10 may include a main body 10c and a sealing portion TS, the main body 10c including the electrode assembly 10a and the shell 10b surrounding the electrode assembly 10a, and the sealing portion TS is formed along the periphery (periphery) of the main body 10c and includes a portion of the shell 10b for sealing the electrode assembly 10a. In this case, the sealing portion TS may include a platform portion T from which the electrodes 11 and 12 are led out, and in addition to the platform portion T, the sealing portion TS may also include a side sealing portion S formed along the side of the main body 10c of the battery cell 10.

[0041] The electrodes 11 and 12 of the battery cell 10 may be led out through the platform portion T, and as will be described later, may be electrically connected to the circuit portion C through the connection portion 56. In the disclosed embodiment, the electrodes 11 and 12 of the battery cell 10 may extend in the first direction Z1, and may be electrically connected to the circuit portion C disposed at a front position of the battery cell 10 in the first direction Z1.

[0042] In the disclosed embodiment, the first direction Z1 may indicate the direction along which the electrodes 11 and 12 of the battery cell 10 extend, or may indicate the direction along which the battery cell 10 and the circuit portion C are arranged, or the direction along which the battery cell 10 and the circuit portion C face each other. In this case, the front position of the battery cell 10 in the first direction Z1 may indicate the front position of the battery cell facing the circuit portion C. Similarly, the front position of the circuit portion C in the first direction Z1 may indicate the front position of the circuit portion C facing the battery cell 10.

[0043] The electrodes 11 and 12 of the battery cell 10 may include a first electrode 11 and a second electrode 12 arranged in the third direction Z3, and as will be described later, the first electrode 11 and the second electrode 12 having different polarities may be respectively connected to a first conductive pad layer 61 and a second conductive pad layer 62 arranged on the circuit portion C. A detailed technical configuration of the conductive pad layer 60 including the first conductive pad layer 61 and the second conductive pad layer 62 will be described in more detail later.

[0044] The circuit portion C may form a charge and discharge path of the battery cell 10. In the disclosed embodiment, the circuit portion C is used to form a charge and discharge path connected to the electrodes 11 and 12 of the battery cell 10, and may form a charge and discharge path between the battery cell 10 and an external device. In the disclosed embodiment, the external device may correspond to an external load that receives discharge power from the battery cell 10 or an external charger that provides charging power to the battery cell 10, and the circuit portion C may form a discharge path from the battery cell 10 to the external load or a charge path from the external charger to the battery cell 10. In various disclosed embodiments, the circuit portion C may include the entire charge and discharge path between the battery cell 10 and the external device, or may include only a portion of the charge and discharge path between the battery cell 10 and the external device.

[0045] When the battery pack according to the disclosed embodiment includes the circuit portion C electrically connected to the battery cell 10, the circuit portion C may include the entire charge and discharge path between the battery cell 10 and the external device, or may include only a portion of the charge and discharge path between the battery cell 10 and the external device. For example, the battery pack according to the disclosed embodiment may include various components as the circuit portion C electrically connected to the battery cell 10, as long as the circuit portion C is electrically connected to the battery cell 10 to form the charge and discharge path of the battery cell 10, and the battery pack may not necessarily include all components connected to the external device.

[0046] The circuit portion C according to the disclosed embodiment may include a circuit board connected to the battery cell 10, that is, a circuit board having a conductor for forming a charge and discharge path of the battery cell 10, such as a rigid circuit board including a relatively rigid insulating substrate or a flexible insulating board including a relatively flexible insulating film. On the circuit board, such a circuit element (not shown) can be arranged, which can obtain state information such as voltage, current and temperature of the battery cell 10 or can control the charging and discharging operation of the battery cell 10 based on the obtained state information of the battery cell 10. In the drawings attached to this specification, the circuit portion C may include a circuit board including an insulating layer 80, and a conductor (not shown) for forming a charge and discharge path of the battery cell 10 may be formed on the circuit board. In the disclosed embodiment, the conductor (not shown) may extend from the connection portion 56 connected to the electrodes 11 and 12 of the battery cell 10. When it is assumed throughout this specification that the connecting portion 56 forms a conductive connection between the electrodes 11 and 12 of the battery cell 10 and the circuit portion C, this may mean that the connecting portion 56 forms a conductive connection between the electrodes 11 and 12 of the battery cell 10 and the wires of the circuit board (e.g., wires formed on the insulating layer 80).

[0047] In the disclosed embodiment, the circuit portion C may include a safety element (not shown) which is disposed on the charge and discharge path of the battery cell 10 and is capable of blocking the charge and discharge current of the battery cell 10 by capturing abnormal conditions of the battery cell 10 such as overheating, overcharging, and overdischarging. For example, in the disclosed embodiment, in order to forcibly reduce or block the charge and discharge current according to the overheating of the battery cell 10 when the battery cell 10 is overheated above a preset threshold temperature, a safety element (not shown) may be prepared on the charge and discharge path of the battery cell 10 and the safety element may include a variable resistor having a resistance that varies with temperature. For example, in the disclosed embodiment, the safety element may include a positive temperature coefficient (PTC), a thermal cutoff (TCO), and the like. For example, the circuit portion C may include a circuit board on which a wire for forming a charge and discharge path of the battery cell 10 is formed and a safety element (not shown) arranged on the circuit board, or may include only a safety element (not shown) that is not supported by the circuit board.

[0048] In the disclosed embodiment, the connection portion 56 may be between the battery cell 10 and the circuit portion C. The connection portion 56 may be between the battery cell 10 and the circuit portion C to form an electrical connection therebetween. In the disclosed embodiment, the connection portion 56 may include a conductive thermocompression bonding layer 50 and a conductive pad layer 60, the conductive pad layer 60 having a concave accommodation space formed in the second direction Z2 to accommodate a portion of the conductive thermocompression bonding layer 50. In the disclosed embodiment, the second direction Z2 may guide the thickness direction of the electrothermal compression bonding layer 50 or the thickness direction of the conductive pad layer 60, and may guide the direction along which the electrothermal compression bonding layer 50 is compressed or the direction along which the conductive pad layer 60 is compressed. The second direction Z2 may correspond to a direction intersecting the first direction Z1 along which the electrodes 11 and 12 of the battery cell 10 extend and the third direction Z3 along which the electrodes 11 and 12 of the battery cell 10 are arranged. In the disclosed embodiment, the second direction Z2 may correspond to a direction perpendicular to the first direction Z1 and the third direction Z3.

[0049] Reference Figure 3 and Figure 4, the conductive hot-press bonding layer 50 forming the electrical connection between the battery cell 10 and the circuit part C may have conductivity through the hot-press bonding between the battery cell 10 and the circuit part C. In the disclosed embodiment, the conductive hot-press bonding layer 50 may refer to a component that is not conductive before hot-press bonding but has conductivity through hot-press bonding. The conductive hot-press bonding layer 50 according to the disclosed embodiment is different from a metal component that can be identified as a conductive material regardless of whether it is hot-pressed or not, and the conductive hot-press bonding layer 50 may refer to a component whose conductivity may be different before and after hot-press bonding. That is, in the disclosed embodiment, the conductive hot-press bonding layer 50 can form an electrical connection between the electrodes 11 and 12 of the battery cell 10 and the circuit part C through the conductive transition of the conductive hot-press bonding layer 50 (i.e., the transition from a non-conductive state (or insulating state) before hot-press bonding to a conductive state after hot-press bonding). Throughout this specification, the conductive transition of the conductive thermocompression bonding layer 50 may refer to the transition from a non-conductive state (or insulating state) before thermocompression bonding to a conductive state after thermocompression bonding, and may refer to the transition from a non-conductive state (or insulating state) to a conductive state through thermocompression bonding.

[0050] In the disclosed specific embodiment, the conductive thermocompression bonding layer 50 may include conductive particles 51 and an insulating resin 52 containing the conductive particles 51. In the disclosed embodiment, the insulating resin 52 may be in a solid phase below the transition temperature, thereby fixing the conductive particles 51, and the insulating resin 52 may be changed to a liquid phase or a gel phase that may have fluidity other than the solid phase above the transition temperature, so that the conductive particles 51 dispersed in the insulating resin 52 may have fluidity. The conductive particles 51 with fluidity may be arranged between the electrodes 11 and 12 of the battery cell 10 and the circuit portion C to form a conductive connection. For example, when the insulating resin 52 with fluidity above the transition temperature is pushed out between the electrodes 11 and 12 of the battery cell 10 and the circuit portion C by the pressure provided by heat (heat) (i.e., the pressure provided in the second direction Z2 to make the electrodes 11 and 12 of the battery cell 10 and the circuit portion C close to each other), the remaining conductive particles 51 may electrically connect the electrodes 11 and 12 of the battery cell 10 to the circuit portion C.

[0051] The conductive pad layer 60 may be formed on the circuit portion C facing the electrodes 11 and 12 of the battery cell 10, and the conductive pad layer 60 may form a connection portion 56 that electrically connects the battery cell 10 to the circuit portion C together with the conductive thermocompression bonding layer 50. In this case, the conductive pad layer 60 may facilitate the conductive transition of the conductive thermocompression bonding layer 50 so that the conductive transition of the conductive thermocompression bonding layer 50 may be smoothly performed. Hereinafter, the configuration in which the conductive thermocompression bonding layer 50 and the conductive pad layer 60 forming the connection portion 56 cooperate with each other to form a conductive connection between the electrodes 11 and 12 of the battery cell 10 and the circuit portion C according to thermocompression bonding will be described.

[0052] The conductive pad layer 60 may include a convex portion 65a that is relatively protruding in the second direction Z2 and a concave portion 65b that is relatively concave in the second direction Z2. In this case, as will be described later, the second direction Z2 may correspond to the thickness direction of the conductive pad layer 60, and may correspond to the direction along which the conductive thermocompression bonding layer 50 is compressed. The conductive pad layer 60 may have a configuration that may facilitate the conductive transition of the conductive thermocompression bonding layer 50. For example, the convex portion 65a may provide a supporting matrix for supporting the conductive particles 51 of the conductive thermocompression bonding layer 50, and the concave portion 65b may provide a concave accommodation space capable of accommodating the insulating resin 52 of the conductive thermocompression bonding layer 50.

[0053] In the disclosed embodiment, the convex portions 65a and the concave portions 65b of the conductive pad layer 60 may be alternately arranged relative to each other while forming the uneven pattern 65. For example, the convex portions 65a and the concave portions 65b of the conductive pad layer 60 may be alternately arranged in a third direction Z3 intersecting with the first direction Z1 along which the electrodes 11 and 12 of the battery cell 10 extend.

[0054] The conductive pad layer 60 can be formed by selectively etching the plating layer formed on the circuit portion C. For example, a conductive pad layer 60 in which the convex portion 65a and the concave portion 65b are alternately arranged can be formed, wherein the convex portion 65a is not etched in the depth direction of the plating layer (i.e., the second direction Z2), and the concave portion 65b is etched in the depth direction. In the disclosed embodiment, the convex portion 65a and the concave portion 65b forming the conductive pad layer 60 can be formed by selectively etching the plating layer including a metal material, and can include the same metal material. For example, the convex portion 65a and the concave portion 65b can include the same metal material to have substantially the same conductivity.

[0055] The convex portions 65a and the concave portions 65b may be alternately arranged in the third direction Z3 to form an uneven pattern 65, and the uneven pattern 65 may include a plurality of convex portions 65a and a plurality of concave portions 65b arranged in the third direction Z3. In the disclosed embodiment, the convex portion 65a may include a plurality of convex portions 65a spaced apart from each other with the concave portions 65b therebetween. Each of the convex portions 65a and the concave portions 65b arranged in a plurality in the third direction Z3 may extend in the first direction Z1, and the convex portions 65a and the concave portions 65b may extend in parallel in the first direction Z1.

[0056] Reference Figures 5 to 7 , the conductive pad layer 60 may include a base portion 60a, the base portion 60a surrounding an uneven pattern 65 in which a plurality of convex portions 65a and a plurality of concave portions 65b are formed. For example, the base portion 60a may form edge portions 60F, 60S, and 60R of the conductive pad layer 60. That is, the base portion 60a may form a front edge portion 60F, a rear edge portion 60R, and a side edge portion 60S, the front edge portion 60F being formed at a front position relatively close to the battery cell 10 to face the battery cell 10 in the first direction Z1, the rear edge portion 60R being formed at a rear position relatively far from the battery cell 10, and the side edge portion 60S connecting the front edge portion 60F to the rear edge portion 60R. For example, in the disclosed embodiment, the conductive pad layer 60 may include a first conductive pad layer 61 and a second conductive pad layer 62 separated from each other. The edge portions 60F, 60S, and 60R of the conductive pad layer 60 may include the edge portions 60F, 60S, and 60R of each of the first conductive pad layer 61 and the second conductive pad layer 62. For example, the side edge portion 60S may include the side edge portion 60S of each of the first conductive pad layer 61 and the second conductive pad layer 62. The base portion 60a may form the edge portions 60F, 60S, and 60R of the conductive pad layer 60 and completely surround the uneven pattern 65 formed in the inner region of the conductive pad layer 60, and may surround the uneven pattern 65 of each of the first conductive pad layer 61 and the second conductive pad layer 62, respectively.

[0057] In the disclosed embodiment, the uneven pattern 65 may correspond to a portion of the conductive pad layer 60 that forms physical contact with the electrodes 11 and 12 of the battery cell 10. To this end, the uneven pattern 65 may be formed at a position offset toward the front position of the conductive pad layer 60 relatively close to the battery cell 10 in the first direction Z1, so that the rear edge portion 60R extending long in the first direction Z1 and having a flat plate shape may be formed at a rear position of the conductive pad layer 60 relatively far from the battery cell 10. As will be described later, around the uneven pattern 65 and around the conductive thermocompression bonding layer 50, a step P may be formed so that the upper surface of the conductive pad layer 60 is significantly protruded than the upper surface of the insulating layer 80 surrounding the conductive pad layer 60. The step P may be formed in the front portion of the front edge portion 60F and the side edge portion 60S facing the battery cell 10, which overlaps with the uneven pattern 65 or the conductive thermocompression bonding layer 50 in the third direction Z3. Technical details about the step P between the conductive pad layer 60 and the insulating layer 80 will be described in more detail later.

[0058] The base portion 60a may protect the uneven pattern 65 while surrounding the uneven pattern 65, and may support the uneven pattern 65. For example, the base portion 60a may be formed at the same level as the convex portion 65a of the uneven pattern 65 in the second direction Z2, and may support the plurality of convex portions 65a while extending across one end and the other end of each of the plurality of convex portions 65a in the third direction Z3. More specifically, the base portion 60a or the edge portions 60F, 60S, and 60R may completely surround the uneven pattern 65 while extending in the first direction Z1 and the third direction Z3 to surround the uneven pattern 65.

[0059] In the disclosed embodiment, the conductive pad layer 60 can be formed by selectively etching the plating layer formed on the circuit portion C, and in this case, the unetched portion can form the base portion 60a and the convex portion 65a, and the selectively etched portion can form the concave portion 65b. In the disclosed embodiment, the conductive pad layer 60 can include the same metal material as a whole, and the base portion 60a, the convex portion 65a and the concave portion 65b forming the conductive pad layer 60 can all include the same metal material. In the disclosed embodiment, the metal material can be a metal material with excellent conductivity, and can include, for example, aluminum or nickel. In the various disclosed embodiments, the conductive pad layer 60 can include two or more different metal materials, for example, a first metal material and a second metal material stacked thereon. Even in this case, because the base portion 60a, the convex portion 65a and the concave portion 65b forming the conductive pad layer 60 all include the first metal material and the second metal material stacked on each other, it can also be said that the base portion 60a, the convex portion 65a and the concave portion 65b include the same metal material.

[0060] As will be described later, the convex portion 65a can be formed by the conductive particles 51 (see Figure 4 ) is connected to the electrodes 11 and 12 of the battery cell 10. In addition, the protrusion 65a and the base portion 60a connected to the protrusion 65a can be connected to the circuit portion C, and the conductive pad layer 60 including the protrusion 65a and the base portion 60a can form a charge and discharge path of the battery cell 10 between the battery cell 10 and the circuit portion C. That is, the base portion 60a can provide a low-resistance charge and discharge path having a larger area (area) than the protrusion 65a.

[0061] In the disclosed embodiment, the electrodes 11 and 12 of the battery cell 10 can be connected to the circuit portion C through the protrusion 65a and the base portion 60a, and the recess 65b including the same metal material as the protrusion 65a and the base portion 60a can also form a charge and discharge path through which the charge and discharge current of the battery cell 10 flows. However, as will be described later, the recess 65b can provide a housing space for housing the insulating resin 52 instead of the conductive particles 51 (refer to Figure 4 ) are directly connected to the electrodes 11 and 12 of the battery cell 10.

[0062] Throughout this specification, the conductive particles 51 (see Figure 4 ) connected to the electrodes 11 and 12 of the battery cell 10 does not mean that the formation of the charge and discharge path of the battery cell 10 is limited to the protrusion 65a that provides a supporting substrate for the conductive particles 51 and the base portion 60a connected to the protrusion 65a. For example, in the various disclosed embodiments, the charge and discharge path of the battery cell 10 can be formed through the entire conductive pad layer 60 including the uneven pattern 65 and the base portion 60a, and the uneven pattern 65 includes the protrusion 65a and the recess 65b. Similarly, in the present specification, the battery cell 10 and the circuit portion C are connected to the conductive particles 51 arranged on the protrusion 65a (refer to Figure 4 ) are connected to each other does not mean that the charge and discharge path of the battery cell 10 is limited to the protrusion 65a. The charge and discharge path of the battery cell 10 can be formed through the portion of the conductive pad layer 60 including the protrusion 65a or the entire conductive pad layer 60.

[0063] Reference Figure 4, the conductive pad layer 60 may be configured so that the conductive transition of the conductive thermocompression bonding layer 50 forming the connection portion 56 together with the conductive pad layer 60 may be smoothly performed. The convex portion 65a of the uneven pattern 65 forming the conductive pad layer 60 may provide a support base for the conductive particles 51 of the conductive thermocompression bonding layer 50, and the concave portion 65b may provide a concave accommodation space capable of accommodating the insulating resin 52 of the conductive thermocompression bonding layer 50. For example, when the conductive thermocompression bonding layer 50 is heated to above the transition temperature, the insulating resin 52 of the conductive thermocompression bonding layer 50 has fluidity. In this case, the insulating resin 52 having fluidity can be accommodated in the concave accommodation space provided by the recess 65b while being pushed from the protrusion 65a into the recess 65b according to the pressure applied between the electrodes 11 and 12 of the battery cell 10 and the circuit part C (i.e., the pressure applied in the second direction Z2 to bring the electrodes 11 and 12 of the battery cell 10 and the circuit part C close to each other), while the conductive particles 51 remaining on the protrusion 65a can electrically connect the electrodes 11 and 12 of the battery cell 10 to the circuit part C, and the conductive particles 51 remaining on the protrusion 65a can electrically connect the electrodes 11 and 12 of the battery cell 10 to the circuit part C.

[0064] More specifically, the recess 65b can provide a housing space for accommodating the insulating resin 52 of the conductive heat-compression bonding layer 50, and can provide a housing space with sufficient volume to accommodate the insulating resin 52, so that the insulating resin 52 pushed into the housing space does not interfere with the conductive contact between the conductive particles 51 remaining on the protrusion 65a and the battery cell 10.

[0065] In the comparative example compared with the disclosure, the conductive pad layer 60 on the flat plate without the uneven pattern 65 can be connected to the electrodes 11 and 12 of the battery cell 10. In this case, because the conductive pad layer 60 on the flat plate does not provide a differentiated support matrix for each component of the conductive thermocompression bonding layer 50, the insulating resin 52 and the conductive particles 51 forming the conductive thermocompression bonding layer 50 are mixed, and the insulating resin 52 interferes with the contact of the conductive particles 51 with the electrodes 11 and 12 of the battery cell 10. As a result, this causes an increase in resistance between the electrodes 11 and 12 of the battery cell 10 and the conductive pad layer 60.

[0066] In the disclosed embodiment, since the conductive pad layer 60 is connected to the electrodes 11 and 12 of the battery cell 10 through the uneven pattern 65 formed on the conductive pad layer 60, a differentiated support substrate can be provided for each component of the conductive thermocompression bonding layer 50 (i.e., the conductive particles 51 and the insulating resin 52) through the uneven pattern 65 of the conductive pad layer 60. More specifically, the conductive pad layer 60 can support the conductive particles 51 through the convex portion 65a of the uneven pattern 65, so that the electrical connection between the conductive particles 51 remaining on the convex portion 65a and the electrodes 11 and 12 of the battery cell 10 can be formed. In addition, since the insulating resin 52 is accommodated by the concave portion 65b of the uneven pattern 65, the insulating resin 52 does not interfere with the contact between the conductive particles 51 remaining and placed on the convex portion 65a and the electrodes 11 and 12 of the battery cell 10.

[0067] Reference Figure 3 In the battery cell 10 according to the disclosed embodiment, the first electrode 11 and the second electrode 12 having different polarities may be arranged in a third direction Z3 intersecting with the first direction Z1 along which the first electrode 11 and the second electrode 12 extend. The first electrode 11 and the second electrode 12 may be connected to the first conductive pad layer 61 and the second conductive pad layer 62, respectively, which are separately arranged. That is, in the disclosed embodiment, the conductive pad layer 60 may include a first conductive pad layer 61 and a second conductive pad layer 62, which are separated from each other in the third direction Z3 and are respectively connected to the first electrode 11 and the second electrode 12 different from each other. In the disclosed embodiment, the first conductive pad layer 61 and the second conductive pad layer 62 may be electrically connected to the first electrode 11 and the second electrode 12 of the battery cell 10 through a conductive thermocompression bonding layer 50 that continuously extends across the first conductive pad layer 61 and the second conductive pad layer 62 in the third direction Z3.

[0068] In the disclosed embodiment, the conductive hot-press bonding layer 50 may have conductivity in the second direction Z2, and may electrically connect the first electrode 11 and the second electrode 12 of the battery cell 10 to the first conductive pad layer 61 and the second conductive pad layer 62, and the first electrode 11 and the second electrode 12 and the first conductive pad layer 61 and the second conductive pad layer 62 are arranged to overlap each other in the second direction Z2 with the conductive hot-press bonding layer 50 between them. However, the conductive hot-press bonding layer 50 does not have conductivity in the third direction Z3, and therefore does not cause an electrical short circuit between the first electrode 11 and the second electrode 12 of the battery cell 10 or between the first conductive pad layer 61 and the second conductive pad layer 62. In the disclosed embodiment, the conductive hot-press bonding layer 50 may have anisotropy in which the conductive properties vary according to the direction, so that the conductive hot-press bonding layer 50 has conductivity in the second direction Z2 and non-conductivity (or insulation) in the third direction Z3. As described above, in the disclosed embodiment, the first conductive pad layer 61 and the second conductive pad layer 62 respectively connected to the first electrode 11 and the second electrode 12 having different polarities can be set to be separated from each other, but the conductive thermocompression bonding layer 50 connecting the first electrode 11 to the first conductive pad layer 61 and the second electrode 12 to the second conductive pad layer 62 can be set to be a single member formed continuously. Therefore, the connection between the first electrode 11 and the second electrode 12 and the first conductive pad layer 61 and the second conductive pad layer 62 can be formed together by one operation. In addition, the first electrode 11 and the second electrode 12 can be electrically connected to the first conductive pad layer 61 and the second conductive pad layer 62 respectively in the second direction Z2 by using the conductive thermocompression bonding layer 50 having anisotropy (the conductive thermocompression bonding layer 50 has different conductive properties depending on the direction), and the electrical short circuit between the first electrode 11 and the second electrode 12 and between the first conductive pad layer 61 and the second conductive pad layer 62 in the third direction Z3 can also be prevented.

[0069] Reference Figure 3 and Figure 4, the conductive hot compression bonding layer 50 according to the disclosed embodiment may have conductivity according to hot compression bonding. In this case, the conductive hot compression bonding layer 50 may have conductivity according to the compression direction (corresponding to the second direction Z2), and may have non-conductivity (or insulation) in a direction different from the compression direction (for example, in a direction perpendicular to the compression direction). For example, in the disclosed embodiment, the conductive hot compression bonding layer 50 may connect the electrodes 11 and 12 of the battery cell 10 to the conductive pad layer 60 while being compressed in the second direction Z2 corresponding to the compression direction. The conductive hot compression bonding layer 50 may include a plurality of conductive particles 51 dispersed on the insulating resin 52. In addition, when the insulating resin 52 having fluidity according to heating is pushed in the second direction Z2 corresponding to the compression direction, the remaining conductive particles 51 may connect the electrodes 11 and 12 of the battery cell 10 to the conductive pad layer 60, and the electrodes 11 and 12 and the conductive pad layer 60 overlap each other in the second direction. However, in the third direction Z3 not corresponding to the compression direction, the electrical connection through the conductive particles 51 may be blocked because the plurality of conductive particles 51 are not continuously arranged or the insulating resin 52 fills the gaps between the plurality of conductive particles 51. In the disclosed specific embodiment, the conductive thermocompression bonding layer 50 may include an anisotropic conductive film (ACF).

[0070] Reference Figures 5 to 7 , an insulating layer 80 surrounding the conductive pad layer 60 may be formed around the conductive pad layer 60. The insulating layer 80 may provide insulation relative to the conductive pad layer 60. For example, the insulating layer 80 may provide electrical insulation between the conductive pad layer 60 and another conductive line of the circuit portion C. In various disclosed embodiments, the circuit portion C may include another conductive line insulated from the conductive line that is conductive with the conductive pad layer 60, and in this case, the insulating layer 80 may provide electrical insulation between the conductive pad layer 60 and the another conductive line.

[0071] The conductive pad layer 60 may be surrounded by the insulating layer 80. Throughout this specification, the conductive pad layer 60 being surrounded by the insulating layer 80 may mean that when the conductive pad layer 60 is formed on the insulating layer 80 in the second direction Z2, the conductive pad layer 60 formed as a relatively narrow area is formed on the insulating layer 80 formed as a relatively large area. In the disclosed embodiment, the conductive pad layer 60 may be formed in an inner region of the insulating layer 80 on a plane formed by the first direction Z1 and the third direction Z3, and the thickness of the conductive pad layer 60 in the second direction Z2 may be exposed from the insulating layer 80. That is, throughout this specification, the conductive pad layer 60 being surrounded by the insulating layer 80 may mean that the conductive pad layer 60 is formed in an inner region of the insulating layer 80 on a plane formed by the first direction Z1 and the third direction Z3. In this case, the conductive pad layer 60 may be formed in an inner region of the insulating layer 80 on a plane formed by the first direction Z1 and the third direction Z3, and the thickness of the conductive pad layer 60 may be exposed from the insulating layer 80 in the second direction Z2.

[0072] In the various disclosed embodiments, the thickness of the conductive pad layer 60 may be surrounded by the insulating layer 80 in the second direction Z2. That is, in the various disclosed embodiments, the conductive pad layer 60 may be formed in an inner region of the insulating layer 80 on a plane formed by the first direction Z1 and the third direction Z3, and at the same time, the thickness of the conductive pad layer 60 may be surrounded by the insulating layer 80 in the second direction Z2. However, as will be described later, even when the thickness of the conductive pad layer 60 is surrounded by the insulating layer 80, the thickness of the conductive pad layer 60 may be exposed around the uneven pattern 65 along the edge portions 60F, 60S, and 60R of the conductive pad layer 60. That is, the upper surface of the conductive pad layer 60 around the uneven pattern 65 may be formed at a higher level than the upper surface of the insulating layer 80, and the upper surface of the conductive pad layer 60 and the upper surface of the insulating layer 80 may be formed to be stepped (staircase-shaped) in the second direction Z2. In other words, the step P formed by the upper surface of the conductive pad layer 60 and the upper surface of the insulating layer 80 may be formed around the uneven pattern 65 along the edge portions 60F, 60S, and 60R of the conductive pad layer 60 .

[0073] Reference Figure 3In the disclosed embodiment, a step P between the conductive pad layer 60 and the insulating layer 80 may be formed around the uneven pattern 65 on the boundary between the conductive pad layer 60 and the insulating layer 80. In this case, the periphery of the uneven pattern 65 may include a boundary overlapping the uneven pattern 65 in at least the third direction Z3 on the boundary between the conductive pad layer 60 and the insulating layer 80. The step P between the conductive pad layer 60 and the insulating layer 80 may significantly protrude the upper surface of the conductive pad layer 60 instead of the upper surface of the insulating layer 80, thereby providing effective pressure concentration for the conductive thermocompression bonding layer 50 formed on the conductive pad layer 60 and preventing a pressure gap of the pressing tool TO due to physical interference with the insulating layer 80.

[0074] In the thermocompression bonding, a certain amount of heat and pressure may be provided to the conductive thermocompression bonding layer 50 between the electrodes 11 and 12 of the battery cell 10 and the conductive pad layer 60, thereby forming a conductive connection between the electrodes 11 and 12 of the battery cell 10 and the conductive pad layer 60. In this case, the electrodes 11 and 12 of the battery cell 10 and the conductive pad layer 60 are pressed (pressed) in the second direction Z by the pressing tool TO so that the electrodes 11 and 12 and the conductive pad layer 60 are close to each other, and the electrodes 11 and 12 and the conductive pad layer 60 are arranged to overlap each other with the conductive thermocompression bonding layer 50 between them, and a certain amount of heat and pressure may be applied to the conductive thermocompression bonding layer 50. In this case, the area pressed by the pressing tool TO corresponds to the pressing area to which the pressing tool TO is projected in the second direction Z2. In the pressing area of ​​the pressing tool TO, the conductive pad layer 60 to be pressed rather than the insulating layer 80 surrounding the conductive pad layer 60 can protrude significantly in the second direction Z2, so that the conductive pad layer 60 rather than the insulating layer 80 can be effectively pressurized, and interference or pressure gap caused by the insulating layer 80 can be prevented.

[0075] Reference Figures 5 to 7In the disclosed embodiment, a step P between the upper surface of the conductive pad layer 60 and the upper surface of the insulating layer 80 may be formed around the uneven pattern 65 along the edge portions 60F, 60S, and 60R of the conductive pad layer 60 and may be formed in the side edge portion 60S of the conductive pad layer 60, which overlaps the uneven pattern in the third direction Z3. In the disclosed embodiment, the step P of the conductive pad layer 60 may also be formed in the front edge portion 60F and the side edge portion 60S, the front edge portion 60F being formed at a position relatively close to the battery cell 10 to face the battery cell 10 in the first direction Z1. In this case, the front edge portion 60F of the conductive pad layer 60 may refer to an edge portion facing the battery cell 10 (i.e., formed at a position relatively close to the battery cell 10) among the edge portions 60F, 60S, and 60R of the conductive pad layer 60. In the disclosed embodiment, the rear edge portion 60R (corresponding to the thickness of the rear edge portion 60R) of the conductive pad layer 60 formed at a position relatively far from the battery cell 10 may be surrounded by the insulating layer 80 in the second direction Z2. For example, the insulating layer 80 may include a thick portion 80a formed to have a relatively large thickness to surround the rear edge portion 60R (corresponding to the thickness of the rear edge portion 60R).

[0076] In the disclosed embodiment, in addition to including the front edge portion 60F and the rear edge portion 60R, the conductive pad layer 60 may further include a side edge portion 60S connecting the front edge portion 60F to the rear edge portion 60R. In the disclosed embodiment, in the front portions of the front edge portion 60F and the side edge portion 60S each formed around the uneven pattern 65, a step P for significantly protruding the upper surface of the conductive pad layer 60 may be formed, and the rear edge portion 60R (corresponding to the thickness of the rear edge portion 60R) and the rear portion of the side edge portion 60S (corresponding to the thickness of the side edge portion 60S) away from the uneven pattern 65 may be surrounded by the insulating layer 80. For example, the insulating layer 80 may include a thick portion 80a formed to have a relatively large thickness to surround the rear edge portion 60R (corresponding to the thickness of the rear edge portion 60R) and the rear portion of the side edge portion 60S (corresponding to the thickness of the side edge portion 60S). In the disclosed embodiment, the thick portion 80a of the insulating layer 80 may provide insulation of the conductive pad layer 60 by surrounding the rear edge portion 60R (corresponding to the thickness of the rear edge portion 60R) and the rear portion of the side edge portion 60S (corresponding to the thickness of the side edge portion 60S).

[0077] In the disclosed embodiment, the step P between the conductive pad layer 60 and the insulating layer 80 may be formed around the uneven pattern 65. In the disclosed various embodiments, the step P between the conductive pad layer 60 and the insulating layer 80 may be formed around the pressing area rather than around the uneven pattern 65. That is, because the step P provides effective pressurization to the conductive thermocompression bonding layer 50 formed on the conductive pad layer 60 by making the conductive pad layer 60 protrude significantly instead of the insulating layer 80, the step P may be formed in the conductive pad layer 60 at a position close to the pressing tool TO (refer to FIG. 1 ). Figure 3 ) around the pressing area corresponding to the projection area.

[0078] For example, the pressing area of ​​the conductive pad layer 60 may correspond to the projection area to which the pressing tool TO is projected in the second direction Z2, and may correspond to the projection area to which the conductive thermocompression bonding layer 50 to be pressed is projected. In the disclosed embodiment, the pressing area may refer to the portion of the uneven pattern 65 overlapping the conductive thermocompression bonding layer 50 and may refer to the portion of the uneven pattern 65 overlapping the conductive thermocompression bonding layer 50 in the first direction Z1 rather than the entire uneven pattern 65, and a step P for effectively pressurizing the conductive thermocompression bonding layer 50 may be formed around the portion of the uneven pattern 65 overlapping the conductive thermocompression bonding layer 50. For example, the step P may be formed in the side edge portion 60S of the conductive pad layer 60 overlapping the conductive thermocompression bonding layer 50 in the third direction Z3, rather than in the side edge portion 60S of the conductive pad layer 60 overlapping the entire uneven pattern 65 in the third direction Z3.

[0079] The pressing area may extend in a third direction Z3 along which the first electrode 11 and the second electrode 12 are arranged, and the pressing tool TO (refer to Figure 3 ), sufficient pressure can be applied to the conductive hot-pressing bonding layer 50 between the first electrode 11 and the second electrode 12 and the first conductive pad layer 61 and the second conductive pad layer 62. In this case, the pressing tool TO can simultaneously press the conductive hot-pressing bonding layer 50 between the first electrode 11 and the second electrode 12 and the first conductive pad layer 61 and the second conductive pad layer 62 by one-time pressurization of the pressing area. In the various disclosed embodiments, the pressing tool TO can press the conductive hot-pressing bonding layer 50 between the first electrode 11 and the second electrode 12 and the first conductive pad layer 61 and the second conductive pad layer 62 at different times by partial pressure on the pressing area. The pressing tool TO may include a heater therein, and in addition to pressurizing the conductive hot-pressing bonding layer 50, the pressing tool TO can provide sufficient heat for the connection between the electrodes 11 and 12 of the battery cell 10 and the conductive pad layer 60.

[0080] In the disclosed embodiment, the conductive pad layer 60 may be formed on the circuit portion C, and the insulating layer 80 may be formed as a part of the circuit portion C. Throughout this specification, the conductive pad layer 60 may be formed on the circuit portion C, and even if the insulating layer 80 is formed as a part of the circuit portion C, the conductive pad layer 60 and the insulating layer 80 may be formed integrally with the circuit portion C. In the disclosed embodiment, the circuit portion C may be formed to have a multilayer structure in which the insulating layer 80 is formed between a plurality of conductive lines, and the conductive pad layer 60 may be formed on the circuit portion C including the insulating layer 80 as one component. For example, a plating layer may be formed on the insulating layer 80 of the circuit portion C, and the conductive pad layer 60 having the uneven pattern 65 formed thereon may be formed by selectively etching the plating layer.

[0081] As an experiment for demonstrating the technical effect of the disclosed embodiment, Fig. 8A The structure of a comparative example for measuring the connection resistance value between the electrode 11 of the battery cell 10 and the conductive pad layer 60 is shown. Figure 8B The structure of the disclosed embodiment for measuring the connection resistance value between the electrode 11 of the battery cell 10 and the conductive pad layer 60 is shown. Fig. 8A and Figure 8B In an experiment for demonstrating the technical effect of the disclosed embodiment, by measuring the value of the connection resistance between the electrode 11 of the battery cell 10 and the conductive pad layer 60 on the charge and discharge path of the battery cell 10 from the electrode 11 of the battery cell 10 to the conductive pad layer 60, the connection resistance values ​​measured on the charge and discharge path of the battery cell 10 are compared; and by comparing the connection resistance values ​​in the comparative example and the disclosed embodiment, it is demonstrated that the technical effect of the disclosed embodiment is that the connection resistance value on the charge and discharge path in the disclosed embodiment is reduced compared to the comparative example. In this case, the connection resistance value may refer to the resistance between the electrode 11 of the battery cell 10 and the conductive pad layer 60, which is formed by the conductive hot-press bonding layer 50.

[0082] More specifically, in this experiment, after measuring the self-resistance value of each of the electrode 11 of the battery cell 10 and the conductive pad layer 60, the connection resistance value between the electrode 11 of the battery cell 10 and the conductive pad layer 60 can be calculated by subtracting the previously measured self-resistance value of the electrode 11 of the battery cell 10 and the conductive pad layer 60 from the resistance value over the entire charge and discharge path between the electrode 11 of the battery cell 10 and the conductive pad layer 60. In this experiment, the connection resistance value between the electrode 11 of the battery cell 10 and the conductive pad layer 60 can be calculated by subtracting the self-resistance value of the electrode 11 of the battery cell 10 and the conductive pad layer 60 from the resistance value measured over the entire charge and discharge path. For example, in this experiment, three measurement points EP1, EP2, and MP are set on the charge and discharge path of the battery cell 10 (the charge and discharge path is formed between the electrode 11 of the battery cell 10 and the conductive pad 60), and the middle measurement point MP is set at the middle position between the electrode 11 of the battery cell 10 and the conductive pad 60, wherein two end measurement points EP1 and EP2 corresponding to the end positions on the charge and discharge path are set. In this case, the middle measurement point MP may correspond to the connection position between the electrode 11 of the battery cell 10 and the conductive pad 60. Therefore, three measurement points EP1, EP2, and MP including two end measurement points EP1 and EP2 and one middle measurement point MP may be set, the resistance value from the end measurement point EP1 set on the electrode 11 of the battery cell 10 to the middle measurement point MP may correspond to the self-resistance value of the electrode 11 of the battery cell 10, the resistance value from the end measurement point EP2 set on the conductive pad 60 to the middle measurement point MP may correspond to the self-resistance value of the conductive pad 60, and the resistance value between the end measurement point EP1 and the end measurement point EP2 may correspond to the resistance value on the entire charge and discharge path. In this case, the resistance value on the entire charge and discharge path may refer to the resistance value measured in the connection state between the electrode 11 of the battery cell 10 and the conductive pad 60. In this experiment, the connection resistance value between the electrode 11 of the battery cell 10 and the conductive pad layer 60 can be calculated by measuring the self-resistance value of the electrode 11 of the battery cell 10 and the self-resistance value of the conductive pad layer 60 in advance, and then subtracting the previously measured self-resistance value of the electrode 11 of the battery cell 10 and the conductive pad layer 60 from the resistance value on the entire charge and discharge path between the electrode 11 of the battery cell 10 and the conductive pad layer 60. In this way, in the disclosed embodiment, because the connection resistance value between the battery cell 10 and the conductive pad layer 60 is calculated by an indirect method of subtracting the self-resistance value of the electrode 11 of the battery cell 10 and the conductive pad layer 60 from the resistance value on the entire charge and discharge path rather than by a direct measurement method, the obtained connection resistance value may be a negative (-) value after the decimal point as will be described later, and the negative (-) value may correspond to an experimental measurement error.That is, as in the disclosed experimental results, a negative (-) value after the decimal point may indicate that the connection resistance value between the electrode 11 of the battery cell 10 and the conductive pad layer 60 may be reduced to a level close to zero.

[0083] Tables 1 and 2 below show experimental results showing resistance values ​​measured in the comparative example and the disclosed embodiment, respectively, when the electrode 11 of the battery cell 10 is formed of a nickel material. The number of experiments performed in the comparative example is different from the number of experiments performed in the disclosed embodiment, and when the connection resistance value between the electrode 11 of the battery cell 10 and the conductive pad layer 60 in the comparative example is compared with the connection resistance value between the electrode 11 of the battery cell 10 and the conductive pad layer 60 in the disclosed embodiment, it can be seen that the connection resistance value in the disclosed embodiment is significantly reduced. That is to say, by comparing the case in which the conductive hot compression bonding layer 50 serving as the intermediary for connection between the electrode 11 of the battery cell 10 and the conductive pad layer 60 is formed on the uneven pattern 65 on the conductive pad layer 60 as in the disclosed embodiment with the case in which the conductive hot compression bonding layer 50 serving as the intermediary for connection between the electrode 11 of the battery cell 10 and the conductive pad layer 60 is formed on the base portion 60a of the conductive pad layer 60 in which the uneven pattern 65 is not formed as in the comparative example, it can be seen that the connection resistance value between the electrode 11 of the battery cell 10 and the conductive pad layer 60 in the disclosed embodiment is significantly reduced.

[0084]

Table 1

[0085]

[0086]

Table 2

[0087]

[0088] Tables 3 and 4 below show such experimental results, which show the resistance values ​​measured in the comparative example and the disclosed embodiment, respectively, when the electrode 11 of the battery cell 10 is formed of an aluminum material. The number of experiments performed in the comparative example is different from the number of experiments performed in the disclosed embodiment. When the connection resistance value between the electrode 11 of the battery cell 10 and the conductive pad layer 60 in the comparative example is compared with the connection resistance value between the electrode 11 of the battery cell 10 and the conductive pad layer 60 in the disclosed embodiment, it can be seen that the connection resistance value in the disclosed embodiment is significantly reduced. As described above, the case where the conductive hot-pressing bonding layer 50 is formed on the uneven pattern 65 on the conductive pad layer 60 as in the disclosed embodiment is compared with the case where the conductive hot-pressing bonding layer 50 is formed on the base portion 60a of the conductive pad layer 60 in which the uneven pattern 65 is not formed as in the comparative example, it can be seen that the connection resistance value between the electrode 11 of the battery cell 10 and the conductive pad layer 60 in the disclosed embodiment is significantly reduced.

[0089]

Table 3

[0090]

[0091]

Table 4

[0092]

[0093] According to the disclosure, it is possible to provide a battery pack that can easily perform a connection process and simultaneously increase the reliability of electrical connection between a battery cell and a circuit part forming a charge and discharge path of the battery cell.

[0094] It should be understood that the embodiments described herein should be considered in a descriptive sense only and not for the purpose of limitation. The description of features or aspects within each embodiment should generally be considered to be applicable to other similar features or aspects in other embodiments. Although one or more embodiments have been described with reference to the accompanying drawings, it will be understood by those of ordinary skill in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the disclosure defined by the appended claims.

Claims

1. A battery pack, comprising: A battery cell including electrodes extending in a first direction; a circuit unit connected to the electrodes of the battery cell; as well as a connecting portion, forming a connection between the electrode of the battery cell and the circuit portion, the connecting portion comprising a conductive heat-compression bonding layer and a conductive pad layer, the conductive pad layer having a plurality of concave accommodation spaces formed in a second direction intersecting the first direction to accommodate a portion of the conductive heat-compression bonding layer, The conductive pad layer includes a convex portion that is relatively protruding in the second direction and a concave portion that is relatively concave in the second direction, and The conductive thermocompression bonding layer includes conductive particles supported on the protrusions and an insulating resin contained in the recesses.

2. The battery pack according to claim 1, wherein: The electrodes include a first electrode and a second electrode arranged in a third direction intersecting the first direction and the second direction, the first electrode and the second electrode having different polarities, The conductive pad layer includes a first conductive pad layer and a second conductive pad layer, and the first conductive pad layer and the second conductive pad layer are separated from each other in the third direction to be connected to the first electrode and the second electrode respectively.

3. The battery pack according to claim 2, wherein: The conductive thermocompression bonding layer is continuously formed between the first electrode and the first conductive pad layer and between the second electrode and the second conductive pad layer along the third direction.

4. The battery pack according to claim 1, wherein: The conductive thermocompression bonding layer is located between the electrode of the battery cell and the conductive pad layer in the second direction.

5. The battery pack according to claim 1, wherein: The recessed portion provides the plurality of concave receiving spaces.

6. The battery pack according to claim 1, wherein: The convex portion and the concave portion extend in parallel in the first direction.

7. The battery pack according to claim 1, wherein: The convex portion and the concave portion include the same metal material.

8. The battery pack according to claim 1, wherein: The conductive pad layer comprises: An uneven pattern in which the convex portions and the concave portions are alternately arranged in a third direction intersecting the first direction and the second direction.

9. The battery pack according to claim 8, wherein: The uneven pattern is formed at a position offset near a front position of the conductive pad layer facing the battery cell.

10. The battery pack according to claim 8, wherein: The uneven pattern is completely surrounded by an edge portion of the conductive pad layer.

11. The battery pack according to claim 8, wherein: An insulating layer is formed around the conductive pad layer.

12. The battery pack according to claim 11, wherein: At least some of the edge portions of the conductive pad layer forming a boundary between the conductive pad layer and the insulating layer form steps so that an upper surface of the conductive pad layer significantly protrudes than an upper surface of the insulating layer in the second direction.

13. The battery pack according to claim 12, wherein: The step is formed around an uneven pattern formed on the conductive pad layer.

14. The battery pack according to claim 12, wherein: The step is formed around the conductive thermocompression bonding layer.

15. The battery pack according to claim 12, wherein: The edge portion of the conductive pad layer includes: a front edge portion formed at a position relatively close to the battery unit along the first direction; a rear edge portion formed at a position relatively far from the battery unit along the first direction; and A side edge portion connects the front edge portion to the rear edge portion.

16. The battery pack according to claim 15, wherein: The step is formed in a front portion of the side edge portion overlapping the uneven pattern in the third direction.

17. The battery pack according to claim 15, wherein: The step is formed in a front portion of the side edge portion overlapping the conductive thermo-compression bonding layer in the third direction.

18. The battery pack according to claim 15, wherein: The step is formed in the front edge portion relatively close to the battery cell in the first direction.

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