Pouch-type battery cell including sensing member and battery module including the same

Abstract

A pouch-type battery cell according to the present invention accommodates an electrode assembly inside a pouch-type battery case, the electrode assembly including a plurality of positive electrodes and a plurality of negative electrodes, a positive electrode tab and a negative electrode tab extending in opposite directions from each of both ends in a full length direction of the electrode assembly, a positive electrode lead connected to the positive electrode tab and a negative electrode lead connected to the negative electrode tab are interposed in a sealing portion of the pouch-type battery case and protrude outward, and the pouch-type battery case may be equipped with a sensing member for detecting voltage.

Description

[Technical field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0159066 dated November 18, 2021, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a pouch-type battery cell including a sensing member and a battery module including the same, more particularly to a pouch-type battery cell in which a sensing member for detecting voltage is mounted in a pouch-type battery case, and a battery module including the same. [Background technology]

[0003] Rechargeable lithium secondary batteries are widely used not only as energy sources for wireless mobile devices or wearable devices worn on the body, but also as energy sources for electric vehicles and hybrid electric vehicles, which are presented as alternatives to existing gasoline and diesel vehicles that cause air pollution.

[0004] Depending on the material and shape of the battery case, the lithium secondary batteries can be classified into cylindrical battery cells and prismatic battery cells in which an electrode assembly is housed inside a metal can, and pouch-type battery cells in which an electrode assembly is housed inside a battery case made of a laminate sheet. The pouch-type battery cells have the advantages of being easily deformed and having a high energy density.

[0005] Generally, since battery packs for electric vehicles are arranged at the bottom of the vehicle, there is a trend to make the height of the battery pack as low as possible. Nevertheless, battery cells are manufactured in a long shape to maximize the capacity of the battery pack.

[0006] As pouch-type battery cells are developed to have a smaller thickness and an increased length, a battery module including bidirectional battery cells in which positive and negative leads protrude in opposite directions has a problem in that a Battery Management System (BMS) requires additional components and space to measure the voltages of all pouch-type battery cells.

[0007] In this regard, FIG. 1 shows a vertical cross-sectional view of a conventional battery module.

[0008] 1, the battery module 100 is formed by stacking a plurality of pouch-type battery cells 110. The pouch-type battery cells 110 are bidirectional battery cells in which a positive electrode lead and a negative electrode lead protrude in opposite directions. A BMS is disposed on one side of the stacked pouch-type battery cells 110.

[0009] The BMS needs to be electrically connected to the battery cells to measure the voltage of all pouch-type battery cells. Meanwhile, electrode leads protruding toward the BMS can be easily connected directly to the BMS, but electrode leads protruding away from the BMS are farther away from the BMS and therefore require a separate structure to connect to the BMS.

[0010] For example, in order to electrically connect the BMS and the electrode lead in Fig. 1, a separate connecting member made of a plate and a wire is required, which is disposed along the path indicated by the dotted line, and a certain space is also required to place the connecting member between the pouch-type battery cells 110.

[0011] However, in consideration of the trend to reduce the height of battery packs, adding a separate connecting member as shown in FIG. 1 may cause a problem of unnecessarily increasing the height of the battery pack.

[0012] In this regard, Patent Document 1 relates to a double-tab cell that is housed inside an envelope-type exterior material and has a positive electrode tab and a negative electrode tab extending in opposite directions from the exterior material, and discloses a double-tab cell that is equipped with a voltage detection terminal that is arranged on at least one of the positive electrode tab and negative electrode tab and detects a tab voltage of the opposite polarity to that of the other tab.

[0013] However, the structure of Patent Document 1 requires additional space to extend the voltage detection terminals to the outside of the battery case.

[0014] Therefore, when stacking a plurality of long pouch-type battery cells, it is necessary to develop a connection method that can form a connection structure for measuring the voltage of all battery cells and that does not reduce the capacity or increase the volume of the pouch-type battery cells. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] Patent No. 3896911 Summary of the Invention [Problem to be solved by the invention]

[0016] The present invention has been made to solve the above problems, and has an object to provide a pouch-type battery cell including a sensing member so that the voltage of all battery cells can be measured without a decrease in capacity or an increase in volume of the pouch-type battery cell when multiple bidirectional pouch-type battery cells are stacked, and a battery module including the same. [Means for solving the problem]

[0017] To achieve this object, the present invention provides a pouch-type battery cell that accommodates an electrode assembly inside a pouch-type battery case, the electrode assembly including a plurality of positive electrodes and a plurality of negative electrodes, a positive electrode tab and a negative electrode tab extending in opposite directions from each of both ends in a full length direction of the electrode assembly, a positive electrode lead connected to the positive electrode tab and a negative electrode lead connected to the negative electrode tab being interposed in a sealing portion of the pouch-type battery case and protruding outward, and the pouch-type battery case may be configured to incorporate a sensing member for detecting voltage.

[0018] The sensing member may include a sensing lead and a wire, the sensing lead extending outward from an outer periphery of the pouch-type battery case, and the wire being disposed within the pouch-type battery case.

[0019] The pouch-type battery case includes an outer coating layer, a metal layer, and an inner adhesive layer, and the wire can be located between the outer coating layer and the metal layer or between the inner adhesive layer and the metal layer.

[0020] An insulating layer may be interposed between the wire and the metal layer.

[0021] The sensing leads may include a first sensing lead and a second sensing lead located at both ends of the wire.

[0022] Both ends of the pouch-type battery case in a full length direction may include a first end and a second end, the first sensing lead may be interposed in a sealing portion at the first end and extend outward, and the second sensing lead may be interposed in a sealing portion at the second end and extend outward.

[0023] The positive electrode lead and the first sensing lead may be interposed in a sealing portion at the first end and extend outward, and the negative electrode lead and the second sensing lead may be interposed in a sealing portion at the second end and extend outward, with the first sensing lead being disposed so as not to overlap with the positive electrode lead and the second sensing lead being disposed so as to overlap with the negative electrode lead.

[0024] The negative electrode lead and the first sensing lead may be interposed in a sealing portion at the first end and extend outward, and the positive electrode lead and the second sensing lead may be interposed in a sealing portion at the second end and extend outward, with the first sensing lead being disposed so as not to overlap with the negative electrode lead and the second sensing lead being disposed so as to overlap with the positive electrode lead.

[0025] The first and second sensing leads may be smaller in size than the positive and negative leads.

[0026] The sensing member may include a fuse.

[0027] The present invention provides a battery module including the pouch-type battery cell, and the battery module includes a battery cell stack in which a plurality of pouch-type battery cells are stacked in close contact with each other, a module housing that accommodates the battery cell stack, a BMS that is disposed on the outside of a first end, which is one of both side ends in the overall length direction of the battery cell stack, and a bus bar plate that is coupled to a sensing lead and an electrode lead, and the bus bar plate may include a sensing lead welded portion and an electrode lead welded portion.

[0028] The BMS is connected to the sensing lead and the electrode lead to measure the voltage of the pouch-type battery cell.

[0029] Moreover, the present invention can also be provided in the form of a combination of various means for solving the above problems. Effect of the Invention

[0030] As described above, the pouch-type battery cell according to the present invention has a sensing member for detecting voltage installed inside the pouch-type battery case, so that the pouch-type battery cell can be provided with a voltage detection member without increasing the volume of the pouch-type battery cell.

[0031] In addition, since the sensing member is connected to an electrode terminal protruding on the opposite side to the voltage measuring device, the sensing member is connected to the voltage measuring device without the need for a separate connecting member, and therefore both the positive and negative electrodes of one battery cell can be electrically connected to the voltage measuring device.

[0032] Furthermore, by providing a fuse in the sensing member, fire and explosion can be prevented, thereby improving safety. [Brief description of the drawings]

[0033] [Figure 1] FIG. 1 is a vertical cross-sectional view of a conventional battery module. [Diagram 2] FIG. 2 is a plan view of a pouch-type battery cell according to the present invention. [Diagram 3] FIG. 3 is an exploded perspective view of FIG. 2. [Figure 4] FIG. 2 is an exploded perspective view of a pouch-type battery case according to one embodiment. [Diagram 5] FIG. 13 is an exploded perspective view of a pouch-type battery case according to another embodiment. [Figure 6] FIG. 2 is a plan view of a battery module according to the present invention. [Figure 7] FIG. 2 is a perspective view of a battery module according to the present invention; [Figure 8] FIG. 2 is a plan view of a bus bar plate according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings, in which a person having ordinary skill in the art to which the present invention pertains can easily carry out the present invention. However, in describing the operation principle of the preferred embodiment of the present invention in detail, detailed description of related well-known functions or configurations will be omitted if it is determined that such detailed description may unnecessarily obscure the gist of the present invention.

[0035] In addition, the same reference numerals are used throughout the drawings for parts having similar functions and actions. Throughout the specification, when a part is said to be connected to another part, this includes not only the case where the part is directly connected to another part, but also the case where the part is indirectly connected via another element between the two parts. In addition, when a part includes a certain component, it does not mean that the other component is excluded, but that the part may further include the other component, unless otherwise specified.

[0036] Furthermore, descriptions that limit or add specific elements are applicable to all inventions and are not limited to a particular invention unless otherwise specified.

[0037] Furthermore, throughout the description of the present invention and the claims, the singular includes the plural unless otherwise stated.

[0038] In addition, throughout the description of the present invention and the claims, unless otherwise stated, "or" includes "and." Therefore, "including A or B" means three cases: including A, including B, or including both A and B.

[0039] The invention will now be explained with reference to the drawings and in conjunction with detailed embodiments.

[0040] FIG. 2 is a plan view of a pouch-type battery cell according to the present invention, and FIG. 3 is an exploded perspective view of FIG.

[0041] 2 and 3, the pouch-type battery cell 110 according to the present invention accommodates an electrode assembly 201 inside a pouch-type battery case 240, and the pouch-type battery case 240 includes a lower case 242 in which an electrode assembly storage portion is formed, and an upper case 241 that is heat-sealed to the lower case 242.

[0042] Unlike the one shown in Fig. 3, the electrode assembly receiving portion may be formed in the upper case, or may be formed in each of the upper case and the lower case. Also, although Fig. 3 shows a form in which the upper case 241 and the lower case 242 are separated, the upper case and the lower case may be connected at one outer periphery of either one side, and the connected portion may be bent and heat-sealed.

[0043] The electrode assembly 201 includes a plurality of positive electrodes and a plurality of negative electrodes, with a positive electrode tab 211 and a negative electrode tab 221 extending in opposite directions from both ends of the electrode assembly in the overall length direction (x). A positive electrode lead 210 connected to the positive electrode tab 211 and a negative electrode lead 220 connected to the negative electrode tab 221 are interposed in a sealing portion 244 of a pouch-type battery case 240 and protrude outward, and the pouch-type battery case incorporates a sensing member 230 for detecting voltage.

[0044] The sensing member 230 includes a first sensing lead 231, a second sensing lead 232, and a wire 233, and the first sensing lead 231 and the second sensing lead 232 are located on both ends of the wire 233. The first sensing lead 231 and the second sensing lead 232 extend outward from the outer periphery of the pouch-type battery case 240, and the wire 233 is disposed inside the pouch-type battery case.

[0045] For convenience of explanation, in FIGS. 2 and 3, the wires of the sensing member are shown as if they were visible from the outside, but the wires are actually installed inside the pouch-type battery case.

[0046] Both ends of the pouch-type battery case 240 in the overall length direction (x) include a first end 251 and a second end 252, and the first sensing lead 231 is interposed in the sealing portion 244 at the first end 251 and extends outward, and the second sensing lead 232 is interposed in the sealing portion 244 at the second end 252 and extends outward.

[0047] In one embodiment, the positive electrode lead 210 and the first sensing lead 231 are interposed in the sealing portion 244 at a first end 251 and extend outward, and the negative electrode lead 220 and the second sensing lead 232 are interposed in the sealing portion 244 at a second end 252 and extend outward, the first sensing lead 231 is disposed so as not to overlap with the positive electrode lead 210, and the second sensing lead 232 is disposed so as to overlap with the negative electrode lead 220. Here, the second sensing lead 232 and the negative electrode lead 220 may be joined by welding.

[0048] In this manner, the second sensing lead 232 and the negative electrode lead 220 are coupled and electrically connected, so that the voltage of the negative electrode lead 220 can be measured by the first sensing lead 231 via the second sensing lead 232 and the wire 233.

[0049] Meanwhile, an insulating protective film can be added to the outer surfaces of the positive electrode lead and the negative electrode lead to ensure adhesion with the pouch-type battery case. In this case, the length of the second sensing lead in the x direction can be made longer than the length of the insulating protective film in the x direction, so that the end of the second sensing lead can be connected to the negative electrode lead.

[0050] 2 and 3, the positions of the positive electrode lead and the negative electrode lead are interchanged, the negative electrode lead and the first sensing lead are interposed in a sealing portion at the first end and extend outward, the positive electrode lead and the second sensing lead are interposed in a sealing portion at the second end and extend outward, the first sensing lead is arranged so as not to overlap with the negative electrode lead, and the second sensing lead is arranged so as to overlap with the positive electrode lead. Here, the second sensing lead and the positive electrode lead may be joined by welding.

[0051] In this manner, the second sensing lead and the positive electrode lead are combined and electrically connected, so that the positive electrode voltage can be measured by the first sensing lead through the second sensing lead and the wire.

[0052] A large current does not flow through the first and second sensing leads, and only a very small current flows through the first and second sensing leads to simply measure the voltage at the BMS. Therefore, the size of the first and second sensing leads may be smaller than the size of the positive and negative leads.

[0053] FIG. 4 is an exploded perspective view of a pouch-type battery case according to one embodiment.

[0054] Referring to FIG. 4, the pouch-type battery case is the upper case 241 shown in FIG.

[0055] The pouch-type battery case includes an outer coating layer 241a, a metal layer 241b, and an inner adhesive layer 241c.

[0056] The outer coating layer must have excellent resistance to the external environment since it protects the battery cell from the outside, and is required to have excellent tensile strength and weather resistance compared to its thickness. For example, polyester-based resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN), polyolefin-based resins such as polyethylene (PE) and polypropylene (PP), polystyrene-based resins such as polystyrene, polyvinyl chloride-based resins, and polyvinylidene chloride-based resins can be used. These materials can be used alone or in combination of two or more, and ONy (oriented nylon film) is often used.

[0057] The metal layer may be made of aluminum (Al) or an aluminum alloy to prevent the inflow of foreign matter such as gas or moisture or the leakage of electrolyte and to improve the strength of the battery case. Examples of aluminum alloys include alloy numbers 8079, 1N30, 8021, 3003, 3004, 3005, 3104, and 3105, which may be used alone or in combination of two or more.

[0058] The inner adhesive layer may be made of a polymer resin that has heat fusion properties, low hygroscopicity to the electrolyte, and is not expanded or eroded by the electrolyte, and more preferably, may be made of a non-oriented polypropylene film (CPP).

[0059] The wire 233 is located between the outer coating layer 241a and the metal layer 241b, and the first sensing lead 231 and the second sensing lead 232 extend outside the outer periphery of the outer coating layer 241a and the metal layer 241b.

[0060] Since an insulating layer 236 is interposed between the wire 233 and the metal layer 241b, even if the metal layer is exposed during the process of forming the pouch-type battery case, degassing process, etc., the metal layer and the wire can be prevented from coming into contact with each other.

[0061] FIG. 4 shows a configuration in which the insulating layer is added only to the portion corresponding to the wire, but it goes without saying that an insulating layer having the same area as the outer coating layer and the metal layer can be added, or an insulating layer having a configuration surrounding the wire can be used.

[0062] The material of the insulating layer is not particularly limited as long as it does not cause chemical changes and can ensure insulation, for example, polyvinyl chloride, epoxy resin, silicon, ethylene propylene rubber, mica, or ceramics.

[0063] FIG. 5 is an exploded perspective view of a pouch-type battery case according to another embodiment.

[0064] 5, in the sensing member 230, the wire 233 is located between the inner adhesive layer 241c and the metal layer 241b, and the insulating layer 236 is located between the wire 233 and the metal layer 241b. Except for this, the contents described in the description with reference to FIG. 4 can be similarly applied.

[0065] Meanwhile, the sensing member may include a fuse in a portion of the wire. For example, the thickness or shape of a portion of the conductor constituting the wire may be changed to allow only a specific current, and when an overcurrent flows, the conductor may break to cut off the electrical connection.

[0066] FIG. 6 is a plan view of a battery module according to the present invention.

[0067] 6, the plurality of pouch-type battery cells 110 are pouch-type battery cells including the sensing members shown in Figures 2 to 5. The plurality of pouch-type battery cells 110 are stacked so as to be connected in series, and a BMS is disposed on one side of the plurality of pouch-type battery cells 110.

[0068] The pouch-type battery cells 110 are bidirectional battery cells in which positive and negative leads protrude in opposite directions, and a sensing member protrudes adjacent to the electrode lead protruding toward the BMS in order to electrically connect the electrode lead protruding in the direction away from the BMS to the BMS. In Fig. 6, the electrical connection between the BMS and the sensing member is indicated by dotted lines, and the connection between the BMS and the electrode lead is indicated by solid lines.

[0069] FIG. 7 is a perspective view of a battery module according to the present invention.

[0070] 7, the battery module includes a battery cell stack in which pouch-type battery cells 110 including the sensing members shown in FIGS. 2 to 5 are stacked in close contact with each other, a module housing 101 that accommodates the battery cell stack, a BMS 260 (shown by dotted lines) disposed on the outside of a first end 251, which is one of both ends in the overall length direction (x) of the battery cell stack, and bus bar plates 271, 272 (shown by dotted lines) that are coupled to the sensing leads and electrode leads. The first sensing lead 231 and the positive electrode lead 210 are coupled to the bus bar plate 271, and the second sensing lead 232 and the negative electrode lead 220 are coupled to the bus bar plate 272 while being coupled to each other so as to overlap each other.

[0071] The BMS 260 is connected to the sensing leads 231, 232, the positive electrode lead 210 and the negative electrode lead 220, and measures the voltages of all the pouch-type battery cells.

[0072] FIG. 8 is a plan view of a bus bar plate according to the present invention.

[0073] 8, the bus bar plate 271 includes a sensing lead weld 274 and an electrode lead weld 278 that are formed so as not to overlap each other. The sensing lead passes through a through hole 273 formed adjacent to the sensing lead weld 274 and protrudes to the outside of the bus bar plate, and is then bent at a right angle and welded to the sensing lead weld 274, and the electrode lead passes through a through hole 277 formed adjacent to the electrode lead weld 278 and protrudes to the outside of the bus bar plate, and is then bent at a right angle and welded to the electrode lead weld 278.

[0074] The bus bar plate 272 shown in FIG. 7 has a configuration in which the sensing lead and the electrode lead are overlapping and joined to each other and welded to the bus bar plate, and includes only the configuration corresponding to the through hole 277 and the electrode lead welding portion 278 shown in FIG.

[0075] As described above, since the pouch-type battery cell according to the present invention includes a sensing member inside the pouch-type battery case, even in the case of a bidirectional battery cell, the resistance of all battery cells can be measured by electrically connecting a resistance measuring device such as a BMS located on the outer periphery of one side to both the positive and negative electrodes.

[0076] Those skilled in the art will appreciate that various applications and modifications within the scope of the present invention will be possible based on the above content. [Explanation of symbols]

[0077] 100 Battery Module 101 Module Housing 110 Pouch-type battery cell 201 Electrode assembly 210 Positive lead 211 Positive electrode tab 220 Negative lead 221 Negative electrode tab 230 Sensing material 231 First Sensing Lead 232 Second Sensing Lead 233 Wire 236 Insulating Layer 240 Pouch-type battery case 241 Upper case 241a Outer coating layer 241b Metal layer 241c internal adhesive layer 242 Lower Case 244 Sealing part 251 First End 252 2nd End 260 BMS 271, 272 Busbar plate 273, 277 Through hole 274 Sensing lead weld 278 Electrode lead weld

Claims

1. A pouch-type battery cell that houses an electrode assembly inside a pouch-type battery case, The electrode assembly includes a plurality of positive electrodes and a plurality of negative electrodes, A positive electrode tab and a negative electrode tab extend in opposite directions from both ends of the electrode assembly in the overall length direction, A positive electrode lead coupled to the positive electrode tab and a negative electrode lead coupled to the negative electrode tab are interposed in a sealing portion of the pouch-type battery case and protrude outward, The pouch-type battery case includes a sensing member that is connected to a voltage measuring element for detecting a voltage, The sensing member includes leads and wires for sensing, the sensing lead extends outward from an outer periphery of the pouch-type battery case, and the wire is housed within the pouch-type battery case; The pouch-type battery case includes an outer coating layer, a metal layer, and an inner adhesive layer; the wire is located between the outer coating layer and the metal layer or between the inner adhesive layer and the metal layer; The leads for sensing include a first sensing lead and a second sensing lead located at both ends of the wire, respectively. Pouch type battery cell.

2. 2. The pouch-type battery cell according to claim 1, wherein an insulating layer is interposed between the wire and the metal layer.

3. The pouch-type battery case has two ends in a length direction, the ends including a first end and a second end, the first sensing lead is interposed in the sealing portion at the first end and extends outward; The pouch-type battery cell according to claim 1 , wherein the second sensing lead is interposed in the sealing portion at the second end and extends outward.

4. the positive electrode lead and the first sensing lead are interposed in the sealing portion at the first end and extend outward, and the negative electrode lead and the second sensing lead are interposed in the sealing portion at the second end and extend outward, The pouch-type battery cell according to claim 3 , wherein the first sensing lead is arranged so as not to overlap with the positive electrode lead, and the second sensing lead is arranged so as to overlap with the negative electrode lead.

5. the negative electrode lead and the first sensing lead are interposed in the sealing portion at the first end and extend outward, and the positive electrode lead and the second sensing lead are interposed in the sealing portion at the second end and extend outward, The pouch-type battery cell according to claim 3 , wherein the first sensing lead is arranged so as not to overlap with the negative electrode lead, and the second sensing lead is arranged so as to overlap with the positive electrode lead.

6. The pouch-type battery cell according to claim 1 , wherein a size of the first sensing lead and the second sensing lead is smaller than a size of the positive electrode lead and the negative electrode lead.

7. The pouch-type battery cell of claim 1 , wherein the sensing member includes a fuse.

8. A battery module including the pouch-type battery cell according to any one of claims 1 to 7, a battery cell stack in which a plurality of the pouch-type battery cells are stacked in close contact with each other; a module housing that houses the battery cell stack; a BMS disposed on an outer side of a first end, which is one of both ends in a length direction of the battery cell stack; a bus bar plate coupled to the sensing leads and the electrode leads; Including, The bus bar plate includes a lead weld for sensing and an electrode lead weld.

9. The battery module of claim 8 , wherein the BMS is connected to the sensing lead and the electrode lead to measure a voltage of the pouch-type battery cell.

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