Battery module with electrolyte leakage detection function and battery pack including the same

Abstract

The present invention relates to a battery module having an electrolyte leakage detection function and a battery pack including the same, and more particularly to a battery module having a bus bar capable of detecting electrolyte leaked from a battery cell and a battery pack including the same.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 2021-0181419, filed on December 17, 2021, and all the contents disclosed in the document of the Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery module having an electrolyte leakage detection function and a battery pack including the same. Specifically, by making the lengths of any one of the bus bars different, when electrolyte leaks inside the battery module, it is possible to detect an increase in the level of the electrolyte and prevent a fire caused by a short circuit outside the cell. The present invention relates to a battery module having an electrolyte leakage detection function and a battery pack including the same.

Background Art

[0003] As the development of technologies and the demand for mobile devices such as smartphones, notebook computers, and digital cameras increase, technologies related to secondary batteries that can be charged and discharged are being actively studied. In addition, secondary batteries are alternative energy sources for fossil fuels that generate air pollutants, and are applied to electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (P-HEVs), and energy storage devices (ESSs).

[0004] Currently widely used types of secondary batteries include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, etc. In general, such unit secondary battery cells are connected in series or in parallel according to the required output voltage or charge-discharge capacity to form a battery module.

[0005] In particular, the use amount of pouch-type lithium-ion batteries having a structure in which a stacked or stacked / folding-type electrode assembly is built into an aluminum laminate sheet pouch-type battery case is gradually increasing due to advantages such as low manufacturing cost and high energy density.

[0006] However, it has been pointed out as a problem that in a pouch-type lithium-ion battery, when the heat-sealed portion is separated, flammable substances such as electrolytes may leak out, posing a fire hazard.

[0007] FIG. 1 is a conceptual diagram for detecting the presence or absence of electrolyte leakage according to the prior art. According to the prior art of FIG. 1, an electrolyte absorption member 10 that is attached to the outside of the cell, absorbs the electrolyte leaking from the cell, and has conductor characteristics by such electrolyte absorption, a power supply unit 20 that is connected to both ends of the electrolyte absorption member and applies a power supply, a resistance unit 30 that is connected between the electrolyte absorption member and the power supply unit, a sensing unit 40 that senses whether a current flows through the resistance unit, and when the sensing unit senses that a current flows through the resistance unit, a control unit 50 that melts a fuse on the charge and discharge path of the battery pack to cut off the charge and discharge current.

[0008] According to the prior art, there is an advantage that the battery module and the battery pack can be protected by detecting the leaked electrolyte, but the overall structure is very complicated, such as absorbing the electrolyte and sensing whether a current flows. Furthermore, since a large number of members have to be further provided, there is a problem that the energy density is also lowered thereby.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0010] In order to solve the above problems, an object of the present invention is to provide a battery module having an electrolyte leakage detection function capable of quickly detecting the presence or absence of electrolyte leakage while having a simple structure, and a battery pack including the same.

[0011] Another object of the present invention is to provide a battery module having an electrolyte leakage detection function capable of grasping the presence or absence of electrolyte leakage without increasing the volume, and a battery pack including the same.

Means for Solving the Problems

[0012] The battery module according to the present invention for achieving such an object is characterized by including a bus bar (300) capable of detecting electrolyte leaked from a battery cell.

[0013] The battery module according to the present invention further includes a module case (100) including a bottom plate (110), a side plate (120), and an upper plate (130), a plurality of battery cells (200) housed inside the module case (100), and a plurality of bus bars (300) for connecting the plurality of battery cells (200) in series or in parallel. One or more of the plurality of bus bars (300) is characterized by including an extension part (320) protruding a predetermined length toward the bottom plate (110) of the module case (100) at the lower end of the bus bar body 310.

[0014] In the battery module according to the present invention, the end of the extension part (320) of the bus bar (300) is characterized by being separated from the upper surface of the bottom plate (110) of the module case (100) by a predetermined distance.

[0015] In the battery module according to the present invention, the bus bar body (310) and the extension part (320) are characterized by being integrally formed.

[0016] In the battery module according to the present invention, the bus bar body (310) and the extension part (320) are characterized by being separable and electrically connected to each other by a connecting part.

[0017] Also, in the battery module according to the present invention, the connecting portion is formed by welding or a thermally conductive adhesive.

[0018] Also, in the battery module according to the present invention, a buffer pad (500) is further provided between the inner surface of the side plate 120 of the module case (100) and the battery cell (200).

[0019] Also, in the battery module according to the present invention, a heat dissipation pad (600) is further provided between the upper surface of the bottom plate 110 of the module case (100) and the battery cell (200).

[0020] Also, in the battery module according to the present invention, a bus bar frame (400) is interposed between the plurality of battery cells (200) and the bus bar (300).

[0021] Also, in the battery module according to the present invention, the battery cell (200) is a pouch-type battery cell.

[0022] Also, the method for manufacturing a battery module according to the present invention includes a first step of preparing a module case (100), a plurality of battery cells (200), and a bus bar (300), and a second step of housing the plurality of battery cells (200) in the module case (100) and electrically connecting the battery cells (200) via the bus bar (300). One or more of the plurality of bus bars (300) is characterized in that it includes an extension portion (320) that protrudes a predetermined length toward the bottom plate (110) of the module case (100) at the lower end of the bus bar body (310).

[0023] Also, the present invention provides a battery pack including the aforementioned battery module.

Advantages of the Invention

[0024] According to the battery module with an electrolyte leakage detection function of the present invention and a battery pack including the same, by providing an extension portion extending toward the bottom of the module case at the lower end of any one bus bar, there is an advantage that the presence or absence of electrolyte leakage can be quickly detected.

[0025] Further, according to the battery module with an electrolyte leakage detection function of the present invention and a battery pack including the same, since a sensor for detecting the electrolyte or a separate control unit is not required, there is an advantage that a decrease in energy density can be prevented.

[0026] Furthermore, according to the battery module with an electrolyte leakage detection function of the present invention and a battery pack including the same, when the level of the leaked electrolyte rises, one bus bar can be detected in advance, so that a short circuit outside the cell can be detected and prevented in advance, and there is an advantage that a sudden fire can be suppressed.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0028] In this application, terms such as "comprising", "having", or "including" are intended to specify the presence of the features, numbers, steps, components, parts, or combinations thereof described in the specification, and it should be understood that they do not preclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0029] Also, the same reference numerals are used for parts having similar functions and operations throughout the drawings. Throughout the specification, when a part is said to be connected to another part, this includes not only the case where they are directly connected, but also the case where they are indirectly connected with other elements interposed therebetween. Also, including a certain component means, unless otherwise stated to the contrary, not excluding other components and further including other components.

[0030] Hereinafter, a battery module having an electrolyte leakage detection function according to the present invention will be described.

[0031] FIG. 2 is a perspective view of a battery module according to a preferred embodiment of the present invention, FIG. 3 is a front view of the battery module shown in FIG. 2, and FIG. 4 is a perspective view of a battery cell mounted on the battery module according to a preferred embodiment of the present invention.

[0032] Also, FIG. 5 is a perspective view of the battery module according to a preferred embodiment of the present invention with the module case removed, and FIG. 6 is a perspective view of the battery module shown in FIG. 5 with a part of the battery cells, bus bar frames, and bus bars separated.

[0033] Referring to FIGS. 2 to 6 together, the battery module according to the present invention includes a module case 100, a plurality of battery cells 200, a plurality of bus bars 300, a bus bar frame 400, a buffer pad 500, and a heat dissipation pad 600.

[0034] First, the module case 100 houses a battery cell 200, a bus bar 300, a bus bar frame 400, a buffer pad 500, and a heat dissipation pad 600, and is for protecting these from external impacts and the like, and can have a substantially hexahedral shape.

[0035] Specifically, it can be composed of a bottom plate 110 and a top plate 130 that respectively support and protect the lower and upper parts of the battery cell 200, and a pair of side plates 120 that support the sides.

[0036] These bottom plate 110, pair of side plates 120, and top plate 130 can be manufactured integrally or separately and then fixed by known means such as bolts. Although the front plate and the rear plate are not shown in the drawings, the front plate and the rear plate can be further provided as needed.

[0037] The battery cells 200 housed inside the module case 100, more specifically pouch - type battery cells, are first stood vertically and then stacked side - by - side horizontally.

[0038] As an example, as shown in FIG. 4, the battery cell 200 includes an upper cell case 210, a lower cell case 220, an electrode assembly (not shown) housed inside the upper and lower cell cases, a sealing portion 230 at the edges of the upper and lower cell cases, a pair of electrode tabs (not shown), a pair of electrode leads including a positive electrode lead 240 and a negative electrode lead 250, one side of which is electrically connected to the electrode tab and the other side of which protrudes outside the cell case, and an insulating film (not shown).

[0039] Specifically, the upper cell case 210 and the lower cell case 220 are provided with pocket - shaped space portions for housing the electrode assembly.

[0040] These cell cases are made of a laminate sheet composed of an outer coating layer, a metal layer, and an inner coating layer, and form a space portion capable of housing the electrode assembly.

[0041] Since the inner coating layer is in direct contact with the electrode assembly, it must have insulation and resistance to electrolytic solution, and also must have sealing properties for external sealing. That is, the sealing part where the inner layers are thermally adhered to each other must have excellent thermal adhesion strength.

[0042] As materials for such an inner coating layer, polyolefin resins such as polypropylene, polyethylene, polyethylene acrylic acid, and polybutylene, which are excellent in chemical resistance and have good sealing properties, polyurethane resins, and polyimide resins can be selected, but it is not limited thereto. Polypropylene, which is excellent in mechanical physical properties such as tensile strength, rigidity, surface hardness, and impact resistance, and chemical resistance, is most preferable.

[0043] The metal layer in contact with the inner coating layer corresponds to a barrier layer that prevents moisture and various gases from penetrating into the battery from the outside. As a suitable material for such a metal layer, an aluminum thin film that is light and has excellent formability can be used.

[0044] And the other side of the metal layer is provided with an outer coating layer. Such an outer coating layer can use a heat-resistant polymer excellent in tensile strength, moisture permeability prevention, and air permeability prevention so as to ensure heat resistance and chemical resistance while protecting the electrode assembly. As an example, nylon or polyethylene terephthalate can be used, but it is not limited thereto.

[0045] On the other hand, the electrode assembly housed inside the upper cell case 210 and the lower cell case 220 can be classified into a stack-type electrode assembly in which a plurality of electrodes are laminated, a jelly-roll-type electrode assembly wound in a state where a separator is interposed between a positive electrode and a negative electrode, a lamination / stack-type electrode assembly in which a plurality of unit cells are laminated, and a stack / folding-type electrode assembly wound in a state where a unit cell is located on a separator sheet.

[0046] Manufacture unit cells to produce the lamination / stack type electrode assembly and the stack / folding type electrode assembly. The unit cell can be a mono-cell in which a separator is interposed between a positive electrode and a negative electrode, or a bi-cell in which the positive electrode, the negative electrode, the positive electrode, or the negative electrode, the positive electrode, and the negative electrode are laminated and a separator is interposed between the positive electrode and the negative electrode.

[0047] The electrode assembly according to the present invention can have a structure in which a negative electrode / separator / positive electrode / separator / negative electrode are laminated. Needless to say, the number of positive electrodes and negative electrodes constituting the electrode assembly can be freely set and used. In addition, a lamination / stack type electrode assembly in which a plurality of unit cells are laminated can also be used. The structure of the electrode assembly can be applied to all of the electrode assemblies described in this specification.

[0048] The positive electrode and the negative electrode of the electrode assembly are each provided with a positive electrode tab and a negative electrode tab, and this pair of tabs are each connected to the positive electrode lead 240 and the negative electrode lead 250 by spot welding or the like and are arranged so as to protrude by a predetermined length outside the cell case.

[0049] Then, the insulating film is located on the upper and lower surfaces of the pair of electrode leads, more specifically, at the sealing portion 230 where the upper cell case 210 and the lower cell case 220 are heat-sealed.

[0050] Therefore, it is possible to prevent the electricity generated from the electrode assembly from flowing into the cell case through the electrode leads, and to maintain the sealing state between the electrode leads and the cell case. Here, the insulating film is preferably made of a non-conductive material that does not conduct electricity well. Generally, although an insulating tape that is easy to adhere to the electrode leads and has a relatively small thickness is often used, it is not limited thereto.

[0051] Although the drawings depict a bipolar battery cell in which the positive electrode lead 240 and the negative electrode lead 250 are positioned to face each other, it may be a unipolar battery cell in which these pair of electrode leads are arranged in the same direction.

[0052] Next, the bus bar will be described. The bus bar 300 is for connecting a plurality of battery cells 200 housed inside the module case 100 in series or in parallel.

[0053] That is, the bus bar 300 is a conductor having low impedance and high current capacity, and a plurality of bus bars 300 are arranged side by side in the direction in which the plurality of battery cells 200 are stacked to connect the battery cells 200 in series or in parallel.

[0054] The bus bar 300 according to the present invention is exemplified as having a plate-like structure with a constant thickness, but is not limited thereto, and can be implemented by changing to various structures capable of electrical connection.

[0055] On the other hand, in the battery module of the present invention, three bus bars 300 are arranged on the front surface portion to electrically connect the battery cells 200, and one of these bus bars 300 is relatively longer than the remaining bus bars.

[0056] Specifically, referring to FIGS. 2, 3, and 5 for explanation, among the three bus bars arranged side by side in the width direction of the module case 100, the bus bar 300 located on the rightmost side includes a bus bar body 310 and an extension portion 320, and the extension portion 320 is positioned to protrude from the lower end portion of the bus bar body 310 toward the bottom plate 110 of the module case 100 by a predetermined length. On the other hand, the remaining two bus bars 300 do not have an extension portion.

[0057] In the process of using the battery module, the thermal fusion sealing part may be separated due to repeated charging and discharging. That is, the thermal fusion part may deteriorate and the electrolyte may leak due to the expansion pressure caused by the gas generated by the irreversible reaction or the repeated use of a high current environment such as rapid charging.

[0058] Of course, in addition to this, the case may also be broken due to external impact or the electrolyte may leak due to various causes such as chemical corrosion.

[0059] Such electrolyte will accumulate at the bottom of the module case. Since the busbars usually mounted on the battery module have a certain size and a certain separation distance from the bottom of the module case, as a result, a large number of busbars will come into contact with the electrolyte at the same time, resulting in a short circuit outside the cell.

[0060] However, as in the present invention, if an extension part is formed on any one of the busbars and arranged to face the bottom of the module case, when the water level of the leaked electrolyte rises, one busbar can be sensed in advance, so that a short circuit outside the cell can be detected and prevented in advance, and thus the occurrence of a sudden fire can be suppressed.

[0061] Here, the busbar body 310 and the extension part 320 constituting the busbar 300 can be integrally formed, but it is more preferable to be a separable type so as to facilitate adjusting the separation distance from the bottom surface of the case. Here, the busbar body 310 and the extension part 320 are made of the same material, and these busbar body 310 and extension part 320 can be connected to each other by known fixing means such as welding, bolts or thermally conductive adhesives.

[0062] The above has been described based on the front part of the battery module, but the same number of busbars are also located on the rear part, and any one of them can also have a shape extending a predetermined length toward the bottom surface of the case.

[0063] The bus bar frame 400 is fixed to the module case 100 while supporting the bus bar 300. Specifically, the leads of the battery cells 200 penetrate through the slits of the bus bar 300 and are then bent, and are then fixed to the bus bar 300 by known fixing means such as laser welding and resistance welding. Here, the bus bar frame 400 is positioned between the battery cell 200 and the bus bar 300 so that these battery cells 200 and bus bar 300 can be stably supported.

[0064] Although three bus bar frames 400 are shown as being mounted in the drawings, this is merely an example, and it can also be composed of one or four or more bus bar frames.

[0065] Next, the buffer pad will be described. The buffer pad 500 is interposed between the inner surface of the side plate 120 of the module case 100 and the battery cell 200. Such a buffer pad 500 is for pressing the battery cell when the battery cell 200 swells.

[0066] The buffer pad 500 can be made of an elastic body or a foam such as a polyurethane material foam, but is not limited thereto.

[0067] On the other hand, a heat dissipation pad 600 can be further provided between the upper surface of the bottom plate 110 of the module case 100 and the battery cell 200.

[0068] The heat dissipation pad 600 releases the heat generated by the battery cell 200 to the outside, and is also for fixing the battery cell 200, and a thermal conductive material (TIM, Thermal Interface Material) is preferred.

[0069] Next, a method for manufacturing a battery module according to a preferred embodiment of the present invention will be described.

[0070] The manufacturing method of the battery module of the present invention includes the steps of preparing a module case 100, a plurality of battery cells 200, and a bus bar 300, and housing the plurality of battery cells 200 in the module case 100 and electrically connecting the battery cells 200 via the bus bar 300.

[0071] Here, it is preferable that any one or more of the plurality of bus bars 300 is provided with an extension portion 320 that protrudes by a predetermined length toward the bottom plate 110 of the module case 100 at the lower end of the bus bar body 310.

[0072] The above-described battery module can constitute a battery pack and can be applied to various devices.

[0073] Although the specific part of the content of the present invention has been described in detail above, such a specific technique is merely a preferred embodiment for those having ordinary knowledge in the art, and the scope of the present invention is not limited thereby. It is obvious to those skilled in the art that various changes and modifications are possible within the scope of the present invention and the scope of the technical idea, and it goes without saying that such variations and modifications also belong to the scope of the appended claims.

Explanation of Reference Numerals

[0074] 100 Module Case 110 Bottom Plate 120 Side Plate 130 Top Plate 200 Battery Cell 210 Upper Cell Case 220 Lower Cell Case 230 Sealing Portion 240 Positive Electrode Lead 250 Negative Electrode Lead 300 Bus Bar 310 Bus Bar Body 320 Extension Portion 400 Bus Bar Frame 500 Buffer Pad 600 Heat Pad

Claims

1. A plurality of battery cells, and a plurality of bus bars for connecting the plurality of battery cells in series or in parallel, wherein one or more of the plurality of bus bars has an extension portion protruding by a predetermined length from other bus bars so as to be able to detect the presence or absence of leakage of the electrolytic solution by contacting the electrolytic solution leaked from the battery cell earlier than the other bus bars, a battery module.

2. Further comprising a module case including a bottom plate, a side plate, and a top plate, wherein the plurality of battery cells are housed inside the module case, and the extension portion protrudes by a predetermined length toward the bottom plate of the module case at the lower end of the bus bar body, the battery module according to claim 1.

3. The end of the extension portion of the bus bar is separated by a predetermined distance from the upper surface of the bottom plate of the module case, the battery module according to claim 2.

4. The bus bar body and the extension portion are integrally formed, the battery module according to claim 3.

5. The bus bar body and the extension portion are separable and are electrically connected to each other by a connecting portion, the battery module according to claim 3.

6. The connecting portion is formed by welding or a thermally conductive adhesive, the battery module according to claim 5.

7. Further comprising a buffer pad between the inner surface of the side plate of the module case and the battery cell, the battery module according to claim 2.

8. Further comprising a heat dissipation pad between the upper surface of the bottom plate of the module case and the battery cell, the battery module according to claim 2.

9. A bus bar frame is interposed between the plurality of battery cells and the bus bar, the battery module according to claim 2.

10. The battery cell is a pouch-type battery cell, the battery module according to claim 2.

11. A battery pack including the battery module according to any one of claims 1 to 10.

12. A method for manufacturing the battery module according to any one of claims 1 to 10, comprising: preparing a module case, a plurality of battery cells, and a bus bar; and housing the plurality of battery cells in the module case and electrically connecting the battery cells via the bus bar. A method for manufacturing a battery module, wherein one or more of a plurality of bus bars are provided with an extension portion that protrudes by a predetermined length from the lower end portion of the bus bar body toward the bottom plate of the module case.

Images