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

Abstract

The present application 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 busbar configured to detect electrolyte leaked from a battery cell and a battery pack including the same.

Description

Technical Field

[0001] This application claims the benefit of priority to Korean Patent Application No. 2021-0181419, filed on December 17, 2021, the entire disclosure of which is incorporated herein by reference.

[0002] This invention relates to a battery module with electrolyte leakage detection function and a battery pack including the battery module, and more specifically, to a battery module with electrolyte leakage detection function and a battery pack including the battery module, the battery module being configured to change the length of any one of the busbars to sense the rise of the electrolyte level when electrolyte leaks in the battery module, thereby preventing fire caused by short circuit outside the battery cell. Background Technology

[0003] With the technological advancements in mobile devices such as smartphones, laptops, and digital cameras, there has been active research into rechargeable and dischargeable secondary batteries. Furthermore, secondary batteries, as an alternative energy source to fossil fuels that contribute to air pollution, have been applied to electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (P-HEVs), and energy storage systems (ESS).

[0004] As widely used rechargeable batteries, there are lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. For this type of single rechargeable battery cell, multiple battery cells are usually connected in series or parallel to form a battery module according to the required output voltage or charge / discharge capacity.

[0005] In particular, due to their advantages of low manufacturing cost and high energy density, the use of pouch-shaped lithium-ion batteries with a structure in which stacked or stacked folded electrode assemblies are mounted in a pouch-shaped battery casing made of aluminum laminates is gradually increasing.

[0006] However, a problem with pouch-type lithium-ion batteries is that when the heat-fused seals separate, flammable materials such as electrolytes can leak, posing a fire hazard.

[0007] Figure 1 This is a conceptual diagram based on conventional technology for sensing electrolyte leakage. Figure 1The conventional technology includes: an electrolyte absorption member 10, which is attached to the outside of the battery cell to absorb electrolyte leaking from the battery cell, and has conductive properties due to the absorption of electrolyte; a power supply unit 20, which is connected to opposite ends of the electrolyte absorption member to apply power to the electrolyte absorption member; a resistor unit 30, which is connected between the electrolyte absorption member and the power supply unit; a sensing unit 40, which is configured to sense whether current is flowing in the resistor unit; and a controller 50, which is configured to cut off the fuse on the charge / discharge path of the battery pack by melting, thereby blocking the charge / discharge current when the sensing unit senses current flowing in the resistor unit.

[0008] The advantage of conventional technology is that it can detect leaking electrolyte, thereby protecting the battery module or battery pack; however, because it absorbs electrolyte and senses whether current is flowing, the overall structure is very complex. In addition, multiple additional components must be added, which reduces the energy density.

[0009] (Existing technical literature)

[0010] (Patent Document 1) Korean Patent Publication No. 1383599 Summary of the Invention

[0011] Technical issues

[0012] The present invention was made in view of the above problems. The purpose of the present invention is to provide a battery module with electrolyte leakage detection function that can quickly detect whether electrolyte is leaking through a simple structure, and a battery pack including the battery module.

[0013] Another object of the present invention is to provide a battery module with electrolyte leakage detection function that can detect electrolyte leakage without increasing volume, and a battery pack including the battery module.

[0014] Technical solution

[0015] To achieve the above objectives, the battery module according to the invention has a busbar 300 configured to detect electrolyte leakage from the battery cell.

[0016] Furthermore, the battery module according to the present invention may include: a module housing 100 including a bottom plate 110, a side plate 120 and a top plate 130; a plurality of battery cells 200 housed in the module housing 100; and a plurality of busbars 300 configured to connect the plurality of battery cells 200 in series or in parallel with each other, at least one of the plurality of busbars 300 may include an extension 320 protruding a predetermined length from the lower end of the busbar body 310 toward the bottom plate 110 of the module housing 100.

[0017] Furthermore, in the battery module according to the present invention, the end of the extension 320 of the busbar 300 may be separated from the upper surface of the bottom plate 110 of the module housing 100 by a predetermined distance.

[0018] Furthermore, in the battery module according to the present invention, the busbar body 310 and the extension 320 may be integral.

[0019] Furthermore, in the battery module according to the invention, the busbar body 310 and the extension 320 may be separate from each other and electrically connected to each other by means of fixing.

[0020] Furthermore, in the battery module according to the invention, the fixing means may be welding or thermally conductive adhesive.

[0021] Furthermore, the battery module according to the present invention may further include an impact-absorbing pad 500 disposed between the inner surface of the side plate 120 of the module housing 100 and the battery cell 200.

[0022] Furthermore, the battery module according to the present invention may further include a heat dissipation pad 600 disposed between the upper surface of the base plate 110 of the module housing 100 and the battery cell 200.

[0023] Furthermore, the battery module according to the invention may further include a busbar frame 400 inserted between the plurality of battery cells 200 and the plurality of busbars 300.

[0024] Furthermore, in the battery module according to the present invention, each of the plurality of battery cells 200 may be a pouch-shaped battery cell.

[0025] Furthermore, the method for manufacturing a battery module according to the present invention includes a first step of preparing a module housing 100, a plurality of battery cells 200, and a plurality of busbars 300; and a step of accommodating the plurality of battery cells 200 in the module housing 100 and electrically connecting the plurality of battery cells 200 to each other via the plurality of busbars 300, wherein at least one of the plurality of busbars 300 includes an extension 320 protruding a predetermined length from the lower end of the busbar body 310 toward the base plate 110 of the module housing 100.

[0026] Furthermore, the present invention provides a battery pack including the aforementioned battery module.

[0027] Technical effect

[0028] The advantages of the battery module with electrolyte leakage detection function and the battery pack including the battery module according to the present invention are that an extension facing the bottom of the module housing is provided at the lower end of any one of the busbars, thereby enabling rapid detection of electrolyte leakage.

[0029] Furthermore, the battery module with electrolyte leakage detection function according to the present invention and the battery pack including the battery module have the advantage that no sensor or separate controller is required to detect electrolyte, thereby preventing a reduction in energy density.

[0030] Furthermore, the advantages of the battery module with electrolyte leakage detection function and the battery pack including the battery module according to the present invention are that when the liquid level of the leaked electrolyte rises, a busbar can sense this in advance, thereby detecting and preventing short circuits outside the battery cell in advance, thus suppressing sudden fires. Attached Figure Description

[0031] Figure 1 This is a conceptual diagram based on conventional technology for sensing whether electrolyte is leaking.

[0032] Figure 2 This is a perspective view of a battery module according to a preferred embodiment of the present invention.

[0033] Figure 3 yes Figure 2 The image shows a front view of the battery module.

[0034] Figure 4 This is a perspective view of a battery cell installed in a battery module according to a preferred embodiment of the present invention.

[0035] Figure 5 This is a perspective view of a battery module according to a preferred embodiment of the present invention with the module housing removed.

[0036] Figure 6 yes Figure 5 The image shows a perspective view of the battery module in some of its separated states, including the battery cells, busbar frame, and busbars. Detailed Implementation

[0037] In this application, it should be understood that the terms “comprising,” “having,” “including,” etc., specify the presence of the stated features, quantities, steps, operations, elements, components, or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, steps, operations, elements, components, or combinations thereof.

[0038] Furthermore, the same reference numerals will be used throughout the accompanying drawings to refer to parts that perform similar functions or operations. In this application, where one part is referred to as being connected to another part, that one part is not only directly connected to the other part, but also indirectly connected to the other part via another part. Moreover, including an element does not imply the exclusion of other elements, but rather means that other elements may be further included, unless otherwise stated.

[0039] The following will describe a battery module with electrolyte leakage detection function according to the present invention.

[0040] Figure 2 This is a perspective view of a battery module according to a preferred embodiment of the present invention. Figure 3 yes Figure 2 The front view of the battery module shown, and Figure 4 This is a perspective view of a battery cell installed in a battery module according to a preferred embodiment of the present invention.

[0041] also, Figure 5 This is a perspective view of a battery module according to a preferred embodiment of the present invention with the module housing removed. Figure 6 yes Figure 5 The image shows a perspective view of the battery module in some of its separated states, including the battery cells, busbar frame, and busbars.

[0042] Reference Figures 2 to 6 The battery module according to the present invention includes a module housing 100, a plurality of battery cells 200, a plurality of busbars 300, a busbar frame 400, an impact absorption pad 500, and a heat dissipation pad 600.

[0043] The module housing 100 protects the battery cell 200, busbar 300, busbar frame 400, shock absorber 500 and heat dissipation pad 600 from external impacts while accommodating them. The module housing 100 may have a generally hexahedral shape.

[0044] Specifically, the module housing may include: a bottom plate 110 and a top plate 130 configured to support and protect the lower and upper parts of the battery unit 200, respectively; and a pair of side plates 120 configured to support the side surfaces of the battery unit.

[0045] The base plate 110, a pair of side plates 120, and the top plate 130 can be manufactured integrally, or they can be manufactured separately and connected to each other using known means such as bolts. Although the front and rear plates are not shown in the drawings, they can be further provided as needed.

[0046] The battery cells 200, more specifically pouch-shaped battery cells, are housed in the module housing 100 and are stacked upright and side by side.

[0047] As an example, such as Figure 4 As shown, the battery cell 200 includes an upper cell housing 210, a lower cell housing 220, an electrode assembly (not shown) housed in the upper and lower cell housings, a sealing portion 230 disposed at the edge of the upper and lower cell housings, a pair of electrode contacts (not shown), a pair of electrode leads consisting of a positive electrode lead 240 and a negative electrode lead 250, and an insulating film (not shown). Each of the positive and negative electrode leads has one side electrically connected to a corresponding electrode contact and another side protruding outward from the cell housing.

[0048] Specifically, each of the upper unit housing 210 and the lower unit housing 220 is provided with a pouch-shaped space portion configured to accommodate the electrode assembly.

[0049] The unit housing uses laminates including an outer coating, a metal layer, and an inner coating to form a space that can accommodate the electrode assembly.

[0050] The internal coating is designed to be in direct contact with the electrode assembly; therefore, it must exhibit high insulation properties and high electrolyte resistance. Furthermore, to provide a hermetically sealed unit housing from the outside, the internal coating must exhibit high sealing performance; that is, the thermally bonded seals between the internal layers must demonstrate excellent thermal bond strength.

[0051] The internal coating may be made of a material selected from polyolefin resins such as polypropylene, polyethylene, ethyl polyacrylate, or polybutene, which exhibit excellent chemical resistance and high sealing performance; polyurethane resins; and polyimide resins. However, the invention is not limited thereto, and polypropylene is most preferably used, which exhibits excellent mechanical and physical properties such as tensile strength, rigidity, surface hardness, and impact resistance, as well as excellent chemical resistance.

[0052] The metal layer positioned adjacent to the inner coating corresponds to a barrier layer configured to prevent moisture or various gases from penetrating into the battery from the outside. Lightweight and easily formed aluminum films are preferred materials for the metal layer.

[0053] An external coating is applied to another surface of the metal layer. The external coating may be made of a heat-resistant polymer exhibiting excellent tensile strength, moisture permeability, and air permeability, thus providing high heat and chemical resistance while protecting the electrode assembly. As an example, the external coating may be made of nylon or polyethylene terephthalate. However, the invention is not limited thereto.

[0054] On the other hand, the electrode assemblies housed in the upper unit housing 210 and the lower unit housing 220 can be classified as: stacked electrode assemblies, which are configured to have a structure in which multiple electrodes are stacked; jelly roll electrode assemblies, which are configured to have a structure in which a positive electrode and a negative electrode are wound with a separator inserted between them; laminated stacked electrode assemblies, which are configured to have a structure in which multiple single cells are stacked; or stacked folded electrode assemblies, which are configured to have a structure in which a separator is wound with the single cell disposed on a separator sheet.

[0055] To construct laminated stacked electrode assemblies and stacked folded electrode assemblies, single-cell batteries are manufactured. A single-cell battery can be a mono-cell configured with a separator inserted between a positive electrode and a negative electrode; or a bi-cell battery configured with a structure in which a positive electrode, a negative electrode, and a positive electrode, or a negative electrode, a positive electrode, and a negative electrode are stacked with a separator inserted between the positive electrode and the negative electrode.

[0056] The electrode assembly according to the present invention can be configured to have a structure in which a negative electrode, a separator, a positive electrode, a separator, and a negative electrode are stacked, and the number of positive and negative electrodes constituting the electrode assembly can be freely set. Furthermore, a laminated stacked electrode assembly configured to have a structure in which multiple individual cells are laminated can be used. The structure of the electrode assembly can be applied to all electrode assemblies described in this application.

[0057] The electrode assembly has a positive electrode contact and a negative electrode contact, respectively. The contact is configured to protrude outward from the unit housing by a predetermined length when connected to the positive electrode lead 240 and the negative electrode lead 250 by spot welding, respectively.

[0058] The insulating film is located on the upper and lower surfaces of each of the pair of electrode leads, and more specifically, on the sealing portion 230 where the upper unit housing 210 and the lower unit housing 220 are thermally fused together.

[0059] As a result, electricity generated from the electrode assembly is prevented from flowing through the electrode leads to the unit housing, and a seal is maintained between the electrode leads and the unit housing. Here, the insulating film is preferably made of a non-conductive material that transmits almost no electricity. Typically, insulating tape with a small thickness and easy attachment to each electrode lead is widely used; however, the invention is not limited thereto.

[0060] Although the figure shows a bidirectional battery cell configured such that the positive electrode lead 240 and the negative electrode lead 250 are positioned facing each other, a unidirectional battery cell configured such that a pair of electrode leads are positioned facing the same direction can be used.

[0061] Next, the busbar will be described. The busbar 300 is configured to connect multiple battery cells 200 housed in the module housing 100 in series or in parallel with each other.

[0062] In other words, the busbar 300 is a conductor with low impedance and high current capacity. Multiple busbars 300 are arranged side by side along the direction in which multiple battery cells 200 are stacked to connect the battery cells 200 in series or in parallel.

[0063] The busbar 300 according to the invention is shown configured as a plate-shaped structure with uniform thickness; however, the invention is not limited thereto, and the busbar can be modified to have various structures capable of electrical connection.

[0064] In addition, in the battery module according to the present invention, three busbars 300 are provided on the front side of the battery module to electrically connect the battery cells 200 to each other, and one busbar 300 is longer than the other busbars.

[0065] Specifically, refer to Figure 2 , Figure 3 and Figure 5 Of the three busbars arranged side-by-side along the width of the module housing 100, the busbar 300 on the right side includes a busbar body 310 and an extension 320, wherein the extension 320 is configured to protrude a predetermined length from the lower end of the busbar body 310 toward the bottom plate 110 of the module housing 100. On the other hand, each of the other two busbars 300 does not have an extension.

[0066] During the use of the battery module, the heat-fused sealing parts may separate from each other due to repeated charging and discharging. That is, the heat-fused parts may deteriorate due to repeated expansion pressure caused by irreversible reactions or gases generated in environments using high current, such as fast charging, which may lead to electrolyte leakage.

[0067] Of course, electrolyte may leak for various reasons, such as tearing caused by external impact or chemical corrosion.

[0068] Electrolyte accumulates on the bottom of the module housing. Typically, the busbars installed to the battery module are of uniform size or distance from the bottom of the housing. As a result, multiple busbars simultaneously come into contact with the electrolyte, causing an external short circuit to the battery cell.

[0069] However, as in this invention, when any one of the busbars has an extension and the extension is positioned facing the bottom of the module housing, the busbar can sense the rise of the leaked electrolyte level in advance, thereby detecting and preventing short circuits outside the battery cell in advance, thus suppressing sudden fires.

[0070] Here, the busbar body 310 and extension 320 constituting the busbar 300 can be integral; however, it is more preferable that the busbar body and extension are separate from each other, making it easy to adjust the distance from the bottom surface of the housing. In this case, the busbar body 310 and extension 320 can be made of the same material, and the busbar body 310 and extension 320 can be connected to each other using known fastening means such as welding, bolts or thermally conductive adhesives.

[0071] The description above focuses on the front of the battery module. However, the same number of busbars can be provided on the back of the battery module, and any one of the busbars can extend a predetermined length toward the bottom surface of the housing.

[0072] The busbar frame 400 is fixed to the module housing 100 while supporting the busbar 300. Specifically, the leads of the battery cell 200 are bent after extending through the slits of the busbar 300 and then fixed to the busbar 300 by known fixing means such as laser welding or resistance welding. The busbar frame 400 is located between the battery cell 200 and the busbar 300 to stably support the battery cell 200 and the busbar 300.

[0073] Although the attached diagram shows three busbar frames 400 installed, this is only an illustration and one or more busbar frames can be installed.

[0074] Next, the shock-absorbing pad will be described. The shock-absorbing pad 500 is inserted between the inner surface of the side plate 120 of the module housing 100 and the battery cell 200. The shock-absorbing pad 500 is configured to press the battery cell 200 when the battery cell expands.

[0075] The impact-absorbing pad 500 is made of an elastomer or foam such as polyurethane foam; however, the invention is not limited thereto.

[0076] Additionally, a heat dissipation pad 600 may be further provided between the upper surface of the base plate 110 of the module housing 100 and the battery unit 200.

[0077] The heat dissipation pad 600 that dissipates heat generated in the battery cell 200 to the outside and secures the battery cell 200 is preferably made of a thermal interface material (TIM).

[0078] Next, a method for manufacturing a battery module according to an embodiment of the present invention will be described.

[0079] The method for manufacturing a battery module according to the present invention includes the following steps: preparing a module housing 100, a plurality of battery cells 200, and a plurality of busbars 300; and accommodating the plurality of battery cells 200 in the module housing 100 and electrically connecting the plurality of battery cells 200 to each other through the plurality of busbars 300.

[0080] Here, preferably at least one of the plurality of busbars 300 includes an extension 320 that protrudes a predetermined length from the lower end of the busbar body 310 toward the base plate 110 of the module housing 100.

[0081] The aforementioned battery modules can form battery packs and can be applied to various devices.

[0082] While the specific details of the invention have been described in detail, those skilled in the art will understand that this detailed description only discloses preferred embodiments of the invention and therefore does not limit the scope of the invention. Consequently, those skilled in the art will understand that various changes and modifications are possible without departing from the scope and concept of the invention, and it will be apparent that such changes and modifications fall within the scope of the appended claims.

[0083] (Refer to the marking description)

[0084] 100: Module housing

[0085] 110: Base plate

[0086] 120: Side panel

[0087] 130: Top plate

[0088] 200: Battery cell

[0089] 210: Upper unit housing

[0090] 220: Lower unit housing

[0091] 230: Sealing part

[0092] 240: Positive lead

[0093] 250: Negative lead

[0094] 300: Busbar

[0095] 310: Busbar Main Body

[0096] 320: Extension

[0097] 400: Busbar Frame

[0098] 500: Shock Absorbing Pad

[0099] 600: Thermal pad.

Claims

1. A battery module having a busbar configured to detect electrolyte leakage from a battery cell. The battery module includes: A modular housing including a base plate, side plates, and a top plate; Multiple battery cells are housed within the module housing; as well as Multiple busbars are configured to connect the multiple battery cells in series or in parallel. At least one of the plurality of busbars is longer than the others and includes an extension protruding a predetermined length from the lower end of the busbar body toward the bottom plate of the module housing to pre-sense the rise of the electrolyte level in the leak.

2. The battery module according to claim 1, wherein the end of the extension of the busbar is separated from the upper surface of the bottom plate of the module housing by a predetermined distance.

3. The battery module according to claim 2, wherein the busbar body and the extension are integral.

4. The battery module according to claim 2, wherein the busbar body and the extension are separate from each other and electrically connected to each other by a fixing means.

5. The battery module according to claim 4, wherein the fixing means is welding or thermally conductive adhesive.

6. The battery module according to claim 1, further comprising an impact-absorbing pad disposed between the inner surface of the side plate of the module housing and the battery cell.

7. The battery module according to claim 1, further comprising a heat dissipation pad disposed between the upper surface of the base plate of the module housing and the battery cell.

8. The battery module according to claim 1, further comprising a busbar frame inserted between the plurality of battery cells and the plurality of busbars.

9. The battery module of claim 1, wherein each of the plurality of battery cells is a pouch cell.

10. A battery pack comprising a battery module according to any one of claims 1 to 9.

11. A method for manufacturing a battery module according to any one of claims 1 to 9, the method comprising the following steps: Fabrication of module housing, multiple battery cells, and multiple busbars; as well as The plurality of battery cells are housed within the module housing and electrically connected to each other via the plurality of busbars, wherein At least one of the plurality of busbars is longer than the others and includes an extension of a predetermined length protruding from the lower end of the busbar body toward the bottom plate of the module housing, in order to pre-sense the rise of the electrolyte level in the leak.

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