KR102167431B1 - Battery Cell Assembly Combined by Single Electrode Lead with Different Thickness - Google Patents

Abstract

The present invention is a battery cell assembly in which a plurality of battery cells in which a plurality of electrode plates are stacked in a battery case are connected in series or in parallel with a separator disposed between a positive electrode plate and a negative electrode plate. A first battery cell having an electrode assembly embedded therein, wherein the first electrode assembly includes: a first battery cell having first electrode tabs formed of first positive electrode tabs and negative electrode tabs; A second battery cell having a second electrode assembly embedded therein, wherein the second electrode assembly includes: a second battery cell having second electrode tabs formed of second positive electrode tabs and negative electrode tabs; And an electrode lead connecting the first electrode tabs and the second electrode tabs to connect the first battery cell and the second battery cell in series or in parallel. Including, wherein the electrode lead, the lead body exposed to the outside of the battery case, a first coupling portion connected to the first electrode tabs at one end portion of the lead body, and a second portion at the other end portion of the lead body It provides a battery cell assembly comprising a second coupling portion connected to the electrode tabs, the lead body is formed to be relatively thicker than the thickness of the first and second coupling portions.

Description

Battery Cell Assembly Combined by Single Electrode Lead with Different Thickness}

The present invention relates to a battery cell assembly combined with a single electrode lead having different thickness.

Secondary batteries that can be charged and discharged are electric vehicles (EV), hybrid electric vehicles (HEVs), and plug-ins that are proposed as a solution to air pollution such as gasoline vehicles and diesel vehicles that use fossil fuels. It is attracting attention as a power source for devices requiring high output and large capacity, including hybrid electric vehicles (Plug-In HEV).

In such a device, a medium- to large-sized battery module in which a plurality of battery cells are electrically connected is used to provide a high output and large capacity.

Medium and large battery modules are preferably manufactured with a small size and weight as much as possible, so prismatic batteries and pouch-type batteries that can be charged with a high degree of integration and have a small weight to capacity are mainly used as battery cells (unit cells) of medium and large battery modules. have.

In particular, pouch-type batteries using an aluminum laminate sheet or the like as an exterior member are attracting a lot of attention due to advantages such as low weight, low manufacturing cost, and easy shape transformation.

Recently, a pouch type battery having a structure in which a stack type or stack/folding type electrode assembly is embedded in a pouch type battery case of an aluminum laminate sheet is attracting a lot of attention due to low manufacturing cost, low weight, and easy shape modification. In addition, its usage is gradually increasing.

In this regard, a battery cell assembly in which two pouch-type secondary batteries are electrically connected in order to provide high output or large capacity has been proposed. A typical electrical connection structure of such a battery cell assembly is shown in FIG. 1. Referring to FIG. 1, a first battery cell 10 and a second battery cell 30, which are pouch-type secondary batteries, are connected in parallel, and each of the first battery cells 10 and the second battery cells 30 A structure in which the formed anode tabs 15 and 35 are coupled to the anode leads 18 and 38 will be described below based on the above structure.

Specifically, the electrode tabs of each of the first and second battery cells 10 and 30 are generally formed of a foil of 0.5 mm or less, and a plurality of electrode tabs (positive electrode tabs or negative electrode tabs) are provided. It is bonded to the electrode lead of (anode lead or cathode lead) by ultrasonic welding.

At this time, when sealing the pouch-type battery cases 14 and 34 by a heat-sealing method, in order to improve the sealing properties of the electrode leads 18 and 38, the upper and lower surfaces of the electrode leads 18 and 38 are provided with a lead film 16a. , 16b) is attached.

In order to obtain a desired high output or large capacity, when the battery cells are electrically connected in series or in parallel, the electrode leads of the respective battery cells must be mutually coupled.

As shown in FIG. 1, in a state in which the first battery cells 10 and the second battery cells 30 are arranged in a lengthwise direction so as to be continuously adjacent to each other, the positive electrode leads 18 and 38 facing each other are A battery cell assembly having a desired electric capacity is manufactured by combining a portion by laser welding or ultrasonic welding.

However, in the process of electrically connecting a plurality of battery cells, the bonding force of the combined pairs of electrode leads may be formed differently from each other, and at this time, there is a problem that the uniformity of bonding of the plurality of pairs of electrode leads is not guaranteed. Can occur.

In particular, the portion where the pair of electrode leads 18 and 38 are joined by welding is exposed to the outside of the pouch-type battery cases 14 and 34, so that when shock or vibration is applied to the battery cell, There is a weak problem.

In addition, when the battery cells 10 and 30 are connected in series or in parallel, the battery cells 10 and 30 may be stacked and arranged. When stacked in the vertical direction, the electrodes are inevitably joined by welding. The leads 18 and 38 have to be bent, and the bent portion of the electrode leads 18 and 38 is structurally weaker than other portions.

In addition, when a shock or vibration is applied to the battery cells and relative motion of the battery cells 10 and 30 coupled through the electrode leads 18 and 38 occurs, the external force is concentrated on the electrode leads exposed to the outside. As it can be, there may be a problem that a disconnection occurs in a part joined by welding.

In addition, the electrode tabs 15 and 35 and the electrode leads 18 and 38 are irreversibly coupled by welding to form an integral body. The electrode tabs 15 and 35 and the electrode leads 18 and 38 are once joined. ) Is impossible to separate, and thus, there is a problem of low compatibility that the operator cannot selectively connect and use the battery cells.

Therefore, even if external vibration or shock is applied, there is a high need for a technology capable of connecting the battery cells freely according to the operator's choice while maintaining a firm bond between the battery cells.

An object of the present invention is to solve the problems of the prior art and technical problems that have been requested from the past.

The inventors of the present application, after repeated in-depth research and various experiments, as described later, when forming the electrode lead into a specific structure, the bonding force between the battery cells is increased, and accordingly, external shock or vibration It was confirmed that the stiffness for the was improved.

In addition, according to the needs of the operator, the bar can freely combine the battery cells, it was confirmed that the compatibility with respect to the electric capacity is improved, and the present invention was completed.

Accordingly, the present invention is a battery cell assembly in which a plurality of battery cells in which a plurality of electrode plates are stacked with a separator interposed between a positive electrode plate and a negative electrode plate are connected in series or in parallel. ,

A first battery cell in which a first electrode assembly is embedded, wherein the first electrode assembly includes: a first battery cell in which first electrode tabs formed of first positive electrode tabs and negative electrode tabs are formed;

A second battery cell having a second electrode assembly embedded therein, wherein the second electrode assembly includes: a second battery cell having second electrode tabs formed of second positive electrode tabs and negative electrode tabs; And

An electrode lead connecting the first electrode tabs and the second electrode tabs to connect the first battery cell and the second battery cell in series or in parallel;

Including, wherein the electrode lead, the lead body exposed to the outside of the battery case, a first coupling portion connected to the first electrode tabs at one end portion of the lead body, and a second portion at the other end portion of the lead body It includes a second coupling portion connected to the electrode tabs, and the lead body is characterized in that the thickness of the lead body is formed relatively thicker than the thickness of the first and second coupling portions.

In one specific example, the battery cell may be formed as a plate-shaped battery cell, and the battery case of the plate-shaped battery cell is, for example, after embedding an electrode assembly in a case of a laminate sheet including a metal layer and a resin layer. It may be made of a structure in which the outer circumferential surface is heat-sealed.

Meanwhile, the electrode lead may be made of a single member. Specifically, in relation to the material thereof, the anode lead of the electrode lead may be made of aluminum, and the negative lead may be made of nickel plated copper.

According to the present invention, the electrode tabs of the first and second battery cells, which are adjacent to each other, are connected by a single electrode lead, and the number of welding processes is greatly reduced, resulting in external shock or vibration. Even if an external force is generated, the bonding force between the electrode terminal and the electrode terminal can be secured.

In this case, the thickness of the lead body may be formed in a size of preferably 110% to 500% based on the thickness of the first and second coupling portions.

If the thickness of the lead body is less than 110% based on the thickness of the first and second coupling portions, the difference between the thickness of the lead body and the thickness of the first and second coupling portions is insignificant. This is not desirable as it may not reach the desired stiffness.

In addition, if the thickness of the lead body exceeds 500% based on the thickness of the first and second coupling portions, the absolute thickness of the lead body becomes too large, and the total volume of the battery module in which the plurality of battery cells are combined will increase. As can be seen, this is also undesirable.

In one specific example, the electrode lead is formed by forming the first coupling portion and the second coupling portion by partial rolling, and the horizontal area of the first coupling portion and the second coupling portion is formed relatively larger than the horizontal area of the lead body. Can be.

Accordingly, by increasing the bonding area with the electrode tabs inside the battery case, which is not affected by external dust or other foreign matter, stable coupling between the electrode lead and the electrode tabs can be achieved.

The partial rolling process may be manufactured through, for example, forming an uneven or protruding portion on a rolling roller and passing an electrode lead between the rolling rollers.

On the other hand, by forming a slope having a predetermined angle in one direction of the shape of the rolling roller, portions of the first coupling portion and the second coupling portion connected to the lead body have a tapered structure in which the thickness increases sequentially toward the lead body. Can be made of.

In one specific example, each of the first and second battery cells may have a structure in which positive electrode tabs and negative electrode tabs face both ends of the battery case.

By forming the positions of the positive electrode tabs and the negative electrode tabs in a structure opposite to both ends of the battery case, the distance between the positive electrode lead and the negative electrode lead can be maximized, and accordingly, the positive electrode lead and the negative electrode due to external shock or vibration Electrical short circuit caused by contact of the lead can be prevented.

Meanwhile, in this structure, the first and second battery cells may be stacked and arranged in a vertical direction in order to increase the space efficiency of the battery cell.

In this case, the electrode lead may be formed to be bent in a "C" shape for a stacked arrangement of the first and second battery cells at a region connected in series or parallel between the battery cells.

In another specific example, each of the first and second battery cells further includes a connecting member coupled to the electrode tabs and having an electrode lead receiving portion for accommodating the electrode lead; The connecting member may be made of a conductive material, and the electrode lead receiving portion may be formed in opposite directions of the electrode tabs.

In this case, the connecting member is positioned between the electrode tabs and the electrode lead and serves to electrically connect the electrode tabs and the electrode lead.

Specifically, a groove capable of accommodating electrode tabs may be formed on a side of the connecting member that faces the electrode tabs, and after the electrode tabs are inserted into the groove, the electrode tabs are connected to the connecting member through rolling or welding. Can be firmly bonded to.

However, since the connecting member is made of a conductive material, as long as the electrode tabs and the electrode lead can be electrically connected, the electrode tabs may be coupled to any part of the connecting member, and may vary according to the manufacturer's selection. to be.

As described above, the electrode lead accommodating portion is formed in the opposite direction of the electrode tabs, so that the electrode lead can be coupled from the outside of the battery case.

At this time, the electrode lead accommodating portion is formed in a slot shape so that the electrode lead is closely accommodated, and may be formed in a structure in which the electrode lead can be inserted and removed.

At this time, the operator can electrically connect the battery cells by selectively inserting the electrode leads into the electrode lead receiving portions respectively formed in a pair of adjacent battery cells, and pulling out the electrode leads inserted in the electrode lead receiving portions again. , There is an effect that the operator can adjust the electrical connection state of the electric cells.

Accordingly, a desired electric capacity can be obtained through the electrode lead without using a bus bar, and a plurality of battery cells can be connected in series or in parallel.

In addition, the connecting member may be formed on the end side of the battery case of the plate-shaped battery cell, and when heat-sealing the outer circumferential surface of the battery case, the battery case may be formed to close and surround the outer circumferential surface of the connecting member.

Accordingly, even if the connecting member is formed, the electrolyte solution injected into the battery case can be prevented from leaking to the outside, and only the electrode lead receiving portion into which the electrode lead can be inserted can be exposed to the outside of the battery case.

On the other hand, an electrode assembly is built into the battery case, and the electrode assembly may be of a winding type, a stack type, or a stack/folding type structure, and other types of electrode assemblies are also applicable.

The present invention also provides a battery module including the battery cell assembly, and provides a device including the battery module. Since the structure of the battery module and the device and a method of manufacturing the same are known in the art, a detailed description thereof will be omitted herein.

As described above, in the battery cell assembly according to the present invention, when connecting the battery cells with a single member, the thickness of the portion of the electrode lead exposed to the outside of the battery case is formed to be relatively thick, so that the external impact Due to the increased rigidity against vibration, the battery cells can be electrically connected stably.

In some cases, a structure in which a connecting member is formed in each battery cell enables selective use of a desired electric capacity, thereby increasing compatibility for use in various devices.

1 is a schematic diagram showing a state in which electrode leads of each of conventional battery cells are joined by welding;
2 is a schematic diagram of a battery cell assembly in which battery cells are electrically connected through single electrode leads having different thicknesses according to an embodiment of the present invention;
3 is a schematic diagram of a battery cell assembly in which battery cells are electrically connected through a connecting member and a single electrode lead having different thicknesses according to another embodiment of the present invention;
4 is a perspective view showing a state before insertion of a connecting member and a single electrode lead having different thicknesses in the configuration of the battery cell assembly of FIG. 3;
5 is a schematic diagram of a battery cell assembly electrically connected through an electrode lead bent in a "c" shape in a stacked state of battery cells according to an embodiment of the present invention;
6 is a perspective view showing an electrode lead formed in a tapered structure according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the drawings according to an embodiment of the present invention, but the scope of the present invention is not limited thereto.

2 is a schematic diagram showing a state in which battery cells are electrically connected through single electrode leads having different thicknesses according to an embodiment of the present invention;

Referring to FIG. 2, a battery cell assembly 100 according to the present invention includes a first battery cell 110 and a second battery cell 130.

The first battery cell 110 and the second battery cell 130 have substantially the same configuration. Hereinafter, only the configuration of the first battery cell 110 will be described, and overlapping of the second battery cell 130 will be described. Description of the same configuration is omitted. Further, even if the drawings are different, redundant descriptions of the same configuration of the battery cell assembly will be omitted.

The first battery cell 110 is a plate-shaped battery cell, and the battery case 114 of the plate-shaped battery cell is a structure in which an electrode assembly is embedded in a case of a laminate sheet including a metal layer and a resin layer, and then the outer circumferential surface is heat-sealed. Consists of.

A first electrode assembly is embedded in the first battery cell 110, and first electrode tabs including first positive electrode tabs 112a and first negative electrode tabs (not shown) are formed in the first electrode assembly.

Although not shown in FIG. 2, in the first battery cell 110, each of the first positive tab 112a formed on the positive plate 112 and the first negative tab (not shown) formed on the negative plate 111 face each other. Direction, and accordingly, by disposing the distance between the first anode tabs 115 and the first cathode tabs (not shown) to the maximum, the first anode tabs 115 and the first cathode tabs (not shown) Electrical short circuit caused by contact can be prevented in advance.

On the other hand, when sealing the outer circumferential surfaces of the pouch-type battery cases 114 and 134 by a heat-sealing method, in order to prevent deterioration of sealing property due to the electrode lead 120, a portion of the pouch-type battery cases 114 and 134 that is heat-sealed Lead films 116a and 116b are attached to the upper and lower surfaces of the electrode lead 120 corresponding to and the lead films 116a and 116b are formed of an insulating material.

The first battery cell 110 and the second battery cell 130 are electrically connected through a single electrode lead 120 made of one member, and in FIG. 2, the first battery cell 110 and the second battery cell ( A structure in which the anodes of 130) are connected in parallel is shown.

The electrode lead 120 includes a lead body 120a exposed to the outside of the battery cases 114 and 134, and a first coupling portion 120b connected to the first positive electrode tabs 115 at one end portion of the lead body 120a. ) And a second coupling portion 120c connected to the second positive electrode tabs 135 at the other end portion of the lead body 120a.

In this case, the thickness of the lead body 120a exposed to the outside of the battery cases 114 and 134 is formed relatively thicker than the thickness of the first coupling portion 120b and the second coupling portion 120c.

3 is a schematic diagram of a battery cell assembly in which battery cells are electrically connected through a connecting member and a single electrode lead having different thicknesses according to another embodiment of the present invention, and FIG. 4 is a configuration of the battery cell assembly of FIG. A perspective view showing a connecting member and a single electrode lead having different thicknesses before insertion

Referring to FIGS. 3 and 4 together, each of the first and second battery cells 210 and 230 is provided with connecting members 218 and 238 capable of accommodating the electrode lead 220.

Hereinafter, referring to the first battery cell 210, the connecting members 218 and 238 serve to electrically connect the first positive electrode tabs 215 and 235 and the electrode lead 220.

The connecting members 218 and 238 are formed of a conductive member, and the first anode tabs 215 are coupled to a portion facing the first electrode assembly by a known method such as welding, and facing the first electrode assembly. An electrode lead accommodating portion 218a capable of accommodating the first coupling portion 220b of the electrode lead is formed at the portion.

As shown in FIG. 4, the first coupling portion 220b of the electrode lead is formed so as to be able to be inserted and withdrawn into the electrode lead receiving portion 218a of the connecting member.

The electrode lead receiving portion 218a physically contacts the first coupling portion 220b by intimate contact with the outer peripheral surface of the first coupling portion 220b while the first coupling portion 220b of the electrode lead is inserted. It is fixed and electrically connected to be energized at the same time, and the second coupling part 220c is also the same.

As described above, in the battery cell assembly 200, by using the connecting members 218 and 238, the lead to the portion of the electrode lead 220 that faces the heat-sealed portion of the pouch-type battery case 214, 234 There is no need to use a film, and there is an effect of more securely protecting the electrode lead 220 in the process of thermally sealing the outer peripheral surfaces of the pouch-type battery cases 214 and 234.

In addition, the electrode lead receiving portion 218a is formed in a slit shape only toward the outer side of the battery case 214, and the pouch-type battery case 214 is in close contact with the outer surface of the connecting member 218 to be sealed, It is formed so that the electrolyte injected into the case 214 does not leak to the outside.

For a more detailed description, referring to FIG. 4, the electrode lead 220 made of a single member is made of a lead body 220a, a first coupling part 220b, and a second coupling part 220c, and The first coupling portion 220b and the second coupling portion 220c extend in a direction opposite to each other with the 220a interposed therebetween.

In FIG. 4, a structure in which the first coupling portion 220b and the second coupling portion 220c extend in a direction opposite to each other in the middle based on the height of the lead body 220a is shown. It goes without saying that the first coupling portion 220b and the second coupling portion 220c may have different heights and extension lengths.

In some cases, a locking jaw (not shown) is formed at an end side of each of the first coupling portion 220b and the second coupling portion 220c, and the locking jaw is fixed to the electrode lead receiving portion 218a. It can be fixed more firmly by forming a locking groove to make it.

5 is a schematic diagram of a battery cell assembly electrically connected through an electrode lead bent in a "c" shape in a state in which battery cells are stacked according to an embodiment of the present invention.

Referring to FIG. 5, in order to efficiently utilize the space in the device, the first battery cells 310 and the second battery cells 330 are stacked and arranged in a vertical direction, and in this state, a "c" shape The first battery cell 310 and the second battery cell 330 are electrically coupled through the electrode lead 320 that is bent in

At this time, the first coupling portion 320b and the second coupling portion 320c of the electrode lead 320 extend in the same direction and are formed in parallel to each other, so that the electrode lead receiving portion and the second battery of the first battery cell The first battery cell 310 and the second battery cell 330 are electrically connected by being inserted into each of the electrode lead receiving portions of the cell.

In addition, the electrode lead 320 that is bent in a "c" shape also, as described above, the thickness of the lead body 320a exposed to the outside of the battery cases 314 and 334 is the first coupling portion 320b and By being formed relatively thicker than the thickness of the second coupling portion 320c, it exhibits an effect of increasing the rigidity against external shock or vibration.

6 is a perspective view showing an electrode lead formed in a tapered structure according to an embodiment of the present invention.

Referring to FIG. 6, in the electrode lead 340 comprising a lead body 340a, a first coupling portion 340b, and a second coupling portion 340c, a first coupling portion 340b and a second coupling portion ( The portion of 340c) has a tapered structure whose thickness is sequentially increased toward the lead body 340a.

At this time, the electrode lead 340 is formed by partial rolling in which only the portions of the first coupling portion 340b and the second coupling portion 340c are rolled, and as such, as manufactured by partial rolling, the first coupling The area in the horizontal direction of the portion 340b and the second coupling portion 340c is formed to be relatively wider than the area in the horizontal direction of the lead body 340a.

As the horizontal area of the first coupling part 340b and the second coupling part 340c is formed relatively larger than the horizontal area of the lead body 340a, electrode tabs (not shown) formed on the electrode plate (not shown) ) Can increase the bonding area and, ultimately, it has the effect of increasing the stability of the electrical connection.

Those of ordinary skill in the field to which the present invention belongs will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

Claims (14)

An electrode assembly in which a plurality of electrode plates are stacked in a state in which a separator is placed between a positive electrode plate and a negative electrode plate is a battery cell assembly in which a plurality of battery cells each embedded in a battery case are connected in series or in parallel,
A first battery cell in which a first electrode assembly is embedded, wherein the first electrode assembly includes: a first battery cell in which first electrode tabs formed of first positive electrode tabs and negative electrode tabs are formed;
A second battery cell having a second electrode assembly embedded therein, wherein the second electrode assembly includes: a second battery cell having second electrode tabs formed of second positive electrode tabs and negative electrode tabs; And
An electrode lead connecting the first electrode tabs and the second electrode tabs to connect the first battery cell and the second battery cell in series or in parallel;
Including,
The electrode lead is connected to the lead body exposed to the outside of the battery case, a first coupling portion connected to the first electrode tabs at one end portion of the lead body, and the second electrode tabs at the other end portion of the lead body It includes a second coupling portion, and the thickness of the lead body is formed relatively thicker than the thickness of the first and second coupling portions,
The lead body has a thickness of 110% to 500% of the thickness of the first and second coupling portions so that the battery cells can be freely coupled and the rigidity against external shock or vibration can be increased, and the lead The body is formed to be bent for the stacking arrangement of the first and second battery cells, and the portions of the first and second coupling portions connected to the lead body are formed to be tapered so as to increase in thickness toward the lead body,
Each of the first and second battery cells further includes a connecting member connected to the electrode tabs and formed with an electrode lead receiving portion for receiving the electrode lead;
The connecting member is made of a conductive material, and the electrode lead receiving portion is formed in opposite directions of the electrode tabs,
The electrode lead receiving portion is formed so that the first and second coupling portions of the electrode lead can be inserted and extracted,
The electrode lead receiving portion is formed in a portion of the connecting member opposite to the electrode tabs, and is formed only toward the outside of the battery case,
The connecting member,
It is formed on the end side of the battery case of the plate-shaped battery cell, and the outer circumferential surface thereof is formed to be sealed in close contact with the battery case so that the electrolyte inside the battery case does not leak to the outside,
Battery cell assembly, characterized in that the battery case is formed to close and surround the outer peripheral surface of the connecting member when thermally sealing the outer peripheral surface of the battery case so that only the electrode lead receiving portion can be exposed to the outside of the battery case. The battery cell assembly of claim 1, wherein the battery cell is a plate-shaped battery cell. The battery cell assembly according to claim 2, wherein the battery case of the plate-shaped battery cell has a structure in which an electrode assembly is embedded in a case of a laminate sheet including a metal layer and a resin layer, and then the outer circumferential surface is heat-sealed. The battery cell assembly of claim 3, wherein the electrode lead is made of a single member. delete The method of claim 4, wherein the electrode lead is formed by forming the first coupling portion and the second coupling portion by partial rolling, so that the horizontal area of the first coupling portion and the second coupling portion is relatively larger than the horizontal area of the lead body. Battery cell assembly, characterized in that. The battery cell assembly of claim 4, wherein each of the first and second battery cells has a structure in which positive tabs and negative tabs face opposite ends of the battery case. The method of claim 7,
The first and second battery cells are stacked and arranged;
The electrode lead is a battery cell assembly, characterized in that it is bent in a "c" shape for the stacking arrangement of the first and second battery cells at a region connected in series or parallel between the battery cells. delete The battery cell assembly of claim 7, wherein the electrode lead receiving portion is formed in a slot shape so that the electrode lead is closely accommodated. delete The battery cell assembly according to any one of claims 1 to 4, 6 to 8, and 10, wherein the electrode assembly has a winding type, a stack type, or a stack/folding type structure. A battery module comprising at least one battery cell assembly according to any one of claims 1 to 4, 6 to 8, and 10. A device comprising the battery module according to claim 13.

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