Battery modules, battery packs, and energy storage systems

Abstract

A battery module according to an embodiment of the present invention includes a battery cell stack in which a plurality of battery cells are stacked, a bus bar frame formed on one or both sides of the battery cell stack, and a bus bar on an outer surface of the bus bar frame, the bus bar being electrically connected to an electrode lead of the battery cell stack, the bus bar including a bus bar body connected to the electrode lead, and a heat-resistant member interposed between the bus bar and the bus bar frame.

Description

Technical Field

[0001] Cross-Reference to Related Applications The present application claims the benefit of priority based on Korean Patent Application No. 10-2023-0060976 filed on May 11, 2023, and all contents disclosed in the literature of said Korean patent application are incorporated as a part of the present specification. Background Art

[0002] In modern society, as the use of portable devices such as mobile phones, laptop computers, video cameras, and digital cameras, as well as energy storage systems (ESS), has become commonplace, development of technologies in related fields has been increasingly active. In addition, rechargeable secondary batteries are a solution to solve problems such as air pollution caused by existing gasoline vehicles that use fossil fuels, and are used as power sources for electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (P-HEVs), and the like, so the need for development of secondary batteries is increasing.

[0003] Currently commercialized secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium secondary batteries, etc. Among them, lithium secondary batteries attract the most attention because they have the advantages of being freely chargeable and dischargeable, low self-discharge rate, and high energy density.

[0004] Figure 1 shows a front view of a battery module with a conventional busbar 30 attached. Figure 2 shows a cross-sectional view of line AA in Figure 1. Figure 1 shows a front view of a battery module or battery pack after the electrode leads 11 have been welded to the busbar 30. The battery module includes a battery cell stack in which a plurality of battery cells 10 are stacked, electrode leads 11 protruding from one or both ends of the battery cells 10, a busbar frame 20, a busbar 30, and end plates 40 at both ends of the battery cell stack. The electrode leads 11 pass through an open slit 21 in the busbar frame 20 and are welded to the busbar 30 on the outer surface of the busbar frame 20. The electrode leads 11 can be electrically connected to the busbar 30. The busbar 30 is made of a metallic material, including, for example, copper, aluminum, or a mixture thereof.

[0005] According to the prior art shown in Figure 1, the busbar frame 20 includes hook-shaped fixing parts 22 at its upper and lower ends, respectively, and the busbar 30 can be fixed to the outer surface of the busbar frame 20 by the hook-shaped fixing parts 22. The cross-sectional view in Figure 2 also shows that the busbar 30 is hook-connected to the hook-shaped fixing parts 22. The upper fixing part 22 has a snap-fit ​​structure, and the lower fixing part 22 has a guide rib structure.

[0006] Furthermore, the busbar frame 20 further includes a busbar support section 23, which supports the busbar 30. This ensures that the busbar support section 23 supports the busbar 30 when welding it or when using the actual battery module or battery pack.

[0007] On the other hand, reducing the thickness of the busbars can reduce the cost of materials required for busbar manufacturing and increase the energy density of the battery module and / or battery pack. However, the heat generated in the busbars during charging and discharging of the battery cells may be transferred to the busbar frame due to the reduced busbar thickness, potentially causing thermal deformation of the injection-molded busbar frame. For example, the fixing portion 22 and / or busbar support portion 23 of the busbar frame 20 shown in Figure 2 may be thermally deformed, and in some cases, the main body of the busbar frame 20 may also be thermally deformed.

[0008] Therefore, a solution is needed that can reduce the thickness of the busbars while simultaneously blocking heat transfer from the busbars to the busbar frame, thereby preventing deformation of the busbar frame. [Overview of the project] [Problems that the invention aims to solve]

[0009] The object of the present invention is to provide a battery module, battery pack, and energy storage system that can reduce the thickness of the busbars while preventing deformation of the busbar frame due to temperature rise of the busbars.

[0010] However, the problems that the embodiments of the present invention aim to solve are not limited to those described above, and can be broadly expanded within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0011] A battery module according to one embodiment of the present invention includes a battery cell stack in which a plurality of battery cells are stacked, a busbar frame formed on one or both sides of the battery cell stack, and a busbar on the outer surface of the busbar frame that is electrically connected to the electrode leads of the battery cell stack, wherein the busbar may include a busbar body connected to the electrode leads and a heat-resistant member interposed between the busbar and the busbar frame.

[0012] The heat-resistant member may include a heat-sealing portion that allows it to be heat-sealed to the busbar frame.

[0013] At least one of the corners of the busbar body includes a recess, in which the heat-resistant member is exposed and the heat-sealed portion can be provided.

[0014] When viewed from the front, the busbar body and the heat-resistant member have the same shape, and the busbar body may further include the recess.

[0015] The exposed heat-resistant member is provided with a hole, through which the heat-resistant member can be joined to the busbar frame.

[0016] The heat-sealed portion may be located at a predetermined distance from the periphery of the recess of the busbar body.

[0017] The heat-sealed portion and the recess of the busbar body may be provided at two corners of the busbar that face each other on the diagonal.

[0018] The heat-sealed portion can be made of the same material as the busbar frame.

[0019] The busbar body is made of a metal material, and the heat-resistant member may be made of a material having a glass transition temperature (Tg) higher than the maximum temperature rise of the busbar body during charging and discharging of the battery cell.

[0020] The heat-resistant member may include a polymer having a middle glass transition temperature (middle Tg) or a high glass transition temperature (high Tg).

[0021] The busbar body and the heat-resistant member can be bonded to each other with an adhesive.

[0022] The adhesive may be a heat-resistant epoxy adhesive.

[0023] The thickness of the busbar main body may be 20% to 80% of the thickness of the entire busbar.

[0024] The busbar includes a slit through which the electrode lead passes, and the slit may be integrally formed at the same position in the busbar main body and the heat-resistant member.

[0025] According to another embodiment of the present invention, a battery pack including the battery module according to the foregoing embodiment can be provided.

[0026] According to still another embodiment of the present invention, an energy storage system including the battery pack according to the foregoing embodiment can be provided. Effects of the Invention

[0027] According to the present invention, by reducing the thickness of the busbar, it is possible to reduce the cost of the material required for manufacturing the busbar and increase the energy density of the battery module and / or the battery pack. In addition, despite the reduction in the thickness of the busbar, deformation of the busbar frame caused by the temperature rise of the busbar can be prevented.

[0028] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the claims. Brief Description of the Drawings

[0029] [Figure 1] It is a front view of a battery module equipped with a busbar according to the prior art. [Figure 2] A cross-sectional view taken along line A-A in Fig. 1 is shown. [Figure 3] It is a front view showing a battery module according to an embodiment of the present invention. [Figure 4] It is a perspective view of a busbar, which is one component of the battery module of Fig. 3 and can be mounted to the battery module. [Figure 5] Figure 4 is an exploded perspective view of the busbar. [Figure 6] This is an enlarged view of the section shown in Figure 3, indicating that the busbar shown in Figure 3 has been installed. [Figure 7] A comparison table of the characteristics of High Tg FR-4 and FR-4 is shown. [Modes for carrying out the invention]

[0030] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings, so that they can be easily implemented by a person with ordinary skill in the art to which the present invention pertains. The present invention can be realized in a variety of different forms and is not limited to the embodiments described herein.

[0031] To clearly explain the present invention, unnecessary explanatory parts have been omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

[0032] Furthermore, the dimensions and thicknesses of each component shown in the drawings are arbitrarily indicated for the sake of explanation, and therefore the present invention is not necessarily limited to what is shown in the drawings. In the drawings, the thicknesses are shown enlarged to clearly represent multiple layers and regions. Also, in the drawings, the thicknesses of some layers and regions are shown exaggerated for the sake of explanation.

[0033] Furthermore, when a layer, membrane, region, plate, or other part is said to be "above" another part, this includes not only the case where it is "directly above" the other part, but also the case where there is another part in between. Conversely, when one part is said to be "directly above" another part, it means that there is no other part in between. Also, being "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "above" in the opposite direction of gravity.

[0034] Furthermore, when a specification states that a part "includes" a certain component, unless otherwise stated, this means that other components are not excluded and that other components may be included.

[0035] Furthermore, throughout the specification, "on a plane" means when the subject is viewed from above, and "on a cross-section" means when the subject is viewed from the side of a cross-section obtained by cutting the subject perpendicularly.

[0036] A battery module according to one embodiment of the present invention will be described below with reference to Figures 3 and 4.

[0037] Figure 3 is a front view showing a battery module according to one embodiment of the present invention. Figure 4 is a perspective view of a busbar, one component of the battery module of Figure 3, which can be mounted on the battery module. Figure 5 is an exploded perspective view of the busbar of Figure 4. Figure 6 is an enlarged view of a portion of Figure 3, showing the busbar of Figure 3 mounted on a busbar frame.

[0038] Referring to Figure 3, the battery module according to this embodiment includes a battery cell stack in which a plurality of battery cells 10 are stacked, electrode leads 11 protruding from one or both ends of the battery cell stack, a bus bar 100, and a bus bar frame 200.

[0039] First, the battery cell 10 is a rechargeable battery, and may consist of, for example, a pouch-type rechargeable battery. Multiple such battery cells 10 may be composed of each other, and multiple battery cells 10 may be stacked on top of each other so as to be electrically connected to each other to form a battery cell stack.

[0040] The busbar 100 is welded to the electrode lead 11 and electrically connected to the electrode lead 11. The busbar frame 200 includes a number of slits 210, and the busbar 100 is positioned corresponding to the slits 210. The electrode lead 11 passes through the slits 210 and is joined to the busbar 100. The busbar frame 200 may be made of, for example, plastic injection molded plastic, and the material of the busbar frame 200 may be the same as that used for a typical busbar frame 200.

[0041] Referring to Figures 4 and 5, the busbar 100 can be broadly composed of two layers: a busbar body 110 electrically connected to the electrode leads 11 and a heat-resistant member 120.

[0042] The busbar body 110 is made of a metallic material and may include, for example, any one selected from copper, iron, aluminum, and alloys thereof. The busbar body 110 is joined to the electrode leads 11 by welding. The electrode leads 11 pass through the slits 130 of the busbar 100 or the space between adjacent busbars 100 and overlap on one side of the busbar body 110 (the side facing outwards from the battery module). The overlapping portion of the electrode leads 11 and the busbar body 110 is welded to electrically connect the electrode leads 11 and the busbar 100.

[0043] The heat-resistant member 120 is interposed between the busbar body 110 and the busbar frame 200. This prevents the heat generated in the busbar body 110 during charging and discharging of the battery cell 10 from being transferred to the injection-molded busbar frame 200, thus preventing the busbar frame 200 from undergoing thermal deformation.

[0044] More specifically, the busbar frame 200 is typically manufactured from plastic. Conventionally, reducing the thickness of the busbar body 110, which is made of metal, could lead to increased heat generation in the busbar body 110 due to resistance, potentially causing thermal deformation of the busbar frame 200. However, according to the present invention, by providing a heat-resistant member 120 between the busbar body 110 and the busbar frame 200, the heat generated in the busbar body 110 is prevented from being transferred to the busbar frame 200, thereby preventing thermal deformation of the busbar frame 200.

[0045] The heat-resistant member 120 is formed in a plate shape and may cover at least one surface of the busbar body 110. More specifically, the heat-resistant member 120 may cover the rear surface facing the busbar frame, one of the two large-area surfaces (front and rear surfaces) of the busbar body 110. The large area of ​​the heat-resistant member 120 may be the same as or larger than the large area of ​​the busbar body 110. The slit 130 is integrally formed at the same position on both the busbar body 110 and the heat-resistant member 120.

[0046] According to the prior art, the bus bar 30 is hook-connected to the bus bar frame 20 by a fixing part 22 (see Figure 1) having a snap-fit ​​structure and a guide rib structure.

[0047] On the other hand, according to one embodiment of the present invention, the busbar 100 is joined to the busbar frame 200 by heat fusion. In other words, the fixing portion 22 having a snap-fit ​​structure and a guide rib structure is removed from the busbar frame 200. Instead, as shown in Figure 6, the busbar 100 is joined to the busbar frame 200 by a heat fusion portion 140. For this purpose, as shown in Figures 4 to 6, at least one corner of the busbar body 110 is cut to expose the heat-resistant member 120. The heat fusion portion 140 can be made of the same material as the busbar frame 200.

[0048] The heat-resistant member 120 may be made of a material having a glass transition temperature (Tg) higher than the maximum temperature rise of the busbar body 110. The heat-resistant member 120 may include, for example, a polymer having a middle glass transition temperature (middle Tg) or a high glass transition temperature (high Tg).

[0049] The heat-resistant member 120 may, for example, have a High Tg (high glass transition temperature). The glass transition temperature of the heat-resistant member 120 may be, for example, 170 degrees Celsius or higher, or 170 degrees Celsius to 300 degrees Celsius, or 200 degrees Celsius to 250 degrees Celsius, or approximately 210 degrees Celsius to 220 degrees Celsius, or 210 degrees Celsius. Alternatively, the heat-resistant member 120 may include, for example, a High Tg FR-4 material, polysulfone, or polynorbornene. In the case of High Tg FR-4, it may have the properties shown in Figure 7, for example. For reference, Figure 7 shows a comparative table illustrating the properties of High Tg FR-4 and FR-4.

[0050] Alternatively, in some cases, if the maximum temperature rise of the busbar body 110 is less than 140 degrees Celsius, the heat-resistant member 120 may have a high Tg (high glass transition temperature), or it may have a middle Tg (medium glass transition temperature). The glass transition temperature of the heat-resistant member 120 may be, for example, 150 degrees Celsius or higher, or for example, between 150 degrees Celsius and 300 degrees Celsius. In this case, the heat-resistant member 120 may include, for example, a middle Tg FR-4 material.

[0051] The busbar body 110 and the heat-resistant member 120 can be bonded together with an adhesive. The adhesive may be a heat-resistant adhesive. For example, it may be a heat-resistant epoxy adhesive. The adhesive may be supplied in sheet form, for example, or it may be supplied in paste form and cured after application. If cured after application, it may be manufactured by methods such as room temperature drying type, room temperature curing type, thermosetting type, high temperature firing type, or UV curing type.

[0052] When viewed from the front (from the outside of the busbar frame), the busbar body 110 and the heat-resistant member 120 have the same shape, and the busbar body 110 may further include the recess 111 described later.

[0053] The heat-sealed portion 140 and the recess 111 may be provided on at least one of the corners of the busbar 100, and may also be provided on two diagonally opposite corners of the busbar 100 as shown in Figures 4 to 6. Alternatively, they may be provided on the entire corner of the busbar 100.

[0054] On the other hand, as described above, a recess 111 is provided at at least one corner so that the heat-sealed portion 140 can be provided, thereby exposing the heat-resistant member 120. For example, the recess 111 can have a recessed shape that is concave (indented) from the periphery of the busbar body 110, and the recess 111 can have a square or circular shape. As shown in Figures 4 to 6, the recess 111 is formed in a square shape, and the corners may, for example, have a 90-degree angle. However, the present invention is not limited to what is shown, and it is sufficient as long as the heat-resistant member 120 is exposed and the heat-sealed portion 140 can be provided, and it can be manufactured in a variety of shapes and structures. For example, the corners of the busbar body 110 can be chamfered, and various other modifications and changes are possible. The recess 111 may be manufactured by cutting the corners of the busbar body 110, or the busbar body 110 may be cast to have the shape of the recess 111.

[0055] The recess 111 of the busbar body 110 may be spaced at a predetermined distance from the periphery of the recess 111 and the heat-fused portion 140 so that the heat-fused portion 140 is not affected by the heat generated during welding when the electrode lead 11 is welded to the busbar body 110.

[0056] A hole 121 is provided on the exposed surface of the heat-resistant member 120. The busbar 100 can be joined to the busbar frame 200 by heat fusion through the hole 121. The heat-fused portion 140 may be, for example, welded through the hole 121. The busbar 100, in which the busbar body 110 and the heat-resistant member 120 are bonded with adhesive, can be joined to the busbar frame 200 by heat fusion at the heat-fused portion 140. Alternatively, the heat-resistant member 120 may be joined to the busbar frame 200 by heat fusion first, and then the aforementioned adhesive may be applied to the heat-resistant member 120 before attaching the busbar body 110.

[0057] According to this embodiment of the present invention, it is possible to reduce the thickness by more than half compared to conventional busbars made of a single metal material. For example, the thickness of the busbar body 110 may be 20% to 80%, 30% to 70%, or 40% to 60% of the total thickness of the busbar 100 (the sum of the thickness of the busbar body 110 and the heat-resistant member 120).

[0058] While conventional busbars have a thickness of, for example, 3 mm, according to the embodiment of the present invention, the thickness of the busbar body 110 can be reduced to, for example, 1.4 mm. In this case, the thickness of the heat-resistant member 120 may be, for example, 1.6 mm, but may be less.

[0059] Compared to conventional busbars made from a single metal material, the thickness can be the same or reduced, and most importantly, the amount of metal required to manufacture the busbar can be reduced, thereby saving overall manufacturing costs. At the same time, the function of the busbar (electrical connection with electrode leads) can be maintained, and deformation of the busbar frame 200 due to the thermal resistance of the busbar can be prevented.

[0060] The busbar frame 200 shown in Figure 3 is connected to end plates 40 and other components to form a battery module. The stack of battery cells 10 can be housed in the module frame, but it can also be provided in a module-less structure where the module frame is omitted. Standard end plates can be used instead of end plates 40.

[0061] Furthermore, the battery module may be included in a battery pack. The battery pack may have a structure in which one or more battery modules according to this embodiment are included, along with a battery management system (BMS) for managing the battery temperature and voltage, and a cooling device, etc., and are packaged together.

[0062] Battery modules and battery packs containing them can be applied to a variety of devices. Such devices may include means of transport such as electric bicycles, electric vehicles, and hybrid vehicles, and / or energy storage systems (ESS). However, the present invention is not limited thereto and is applicable to a variety of devices in which battery modules and battery packs containing them can be used, and this also falls within the scope of the present invention.

[0063] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto. Various modifications and improvements made by those skilled in the art, utilizing the basic concepts of the present invention as defined in the claims, also fall within the scope of the present invention. [Explanation of Symbols]

[0064] 10: Battery cell stack 11: Electrode Leads 20: Busbar Frame 30: Bus bar 40: End plate 100: Bus bar 110: Busbar body 120: Heat-resistant material 130: Slit 140: Heat-sealed joint 200: Busbar Frame 210: Slit

Claims

1. A battery cell stack, in which multiple battery cells are stacked; A busbar frame formed on one or both sides of the battery cell stack; and The busbar frame includes busbars on its outer surface that are electrically connected to the electrode leads of the battery cell stack. The busbar includes a busbar body connected to the electrode lead, and a heat-resistant member interposed between the busbar and the busbar frame. The heat-resistant member prevents heat generated in the busbar body from being transferred to the busbar frame. A battery module including a heat-sealing section that heat-seals the heat-resistant member to the busbar frame.

2. The battery module according to claim 1, wherein at least one of the corners of the busbar body includes a recess, and the heat-resistant member is exposed in the recess to provide the heat-sealed portion.

3. The battery module according to claim 2, wherein the busbar body further includes the recess, and when viewed from the front, the busbar body excluding the recess has the same shape as the heat-resistant member.

4. The battery module according to claim 2, wherein the exposed heat-resistant member is provided with a hole, and the heat-resistant member is joined to the busbar frame through the hole.

5. The battery module according to claim 2, wherein the heat-sealed portion is spaced a predetermined distance from the periphery of the recess of the busbar body.

6. The battery module according to claim 2, wherein the heat-sealed portion and the recess of the busbar body are provided at two corners of the busbar that face each other on the diagonal.

7. The battery module according to claim 2, wherein the heat-sealed portion is made of the same material as the busbar frame.

8. A battery cell laminate in which multiple battery cells are stacked; A busbar frame formed on one or both sides of the battery cell stack; and The busbar frame includes busbars on its outer surface that are electrically connected to the electrode leads of the battery cell stack. The busbar includes a busbar body connected to the electrode lead, and a heat-resistant member interposed between the busbar and the busbar frame. The heat-resistant member prevents heat generated in the busbar body from being transferred to the busbar frame. The busbar body is made of metal, The heat-resistant member is made of a material having a glass transition temperature (Tg) higher than the maximum temperature rise of the busbar body during charging and discharging of the battery cell, in a battery module.

9. The battery module according to claim 8, wherein the heat-resistant member comprises a polymer having a glass transition temperature of 150 degrees Celsius or more and 300 degrees Celsius or 170 degrees Celsius or more and 300 degrees Celsius or less.

10. A battery cell laminate in which multiple battery cells are stacked; A busbar frame formed on one or both sides of the battery cell stack; and The busbar frame includes busbars on its outer surface that are electrically connected to the electrode leads of the battery cell stack. The busbar includes a busbar body connected to the electrode lead, and a heat-resistant member interposed between the busbar and the busbar frame. The heat-resistant member prevents heat generated in the busbar body from being transferred to the busbar frame. A battery module in which the busbar body and the heat-resistant member are bonded to each other with an adhesive.

11. The battery module according to claim 10, wherein the adhesive is a heat-resistant epoxy adhesive.

12. A battery cell laminate in which multiple battery cells are stacked; A busbar frame formed on one or both sides of the battery cell stack; and The busbar frame includes busbars on its outer surface that are electrically connected to the electrode leads of the battery cell stack. The busbar includes a busbar body connected to the electrode lead, and a heat-resistant member interposed between the busbar and the busbar frame. The heat-resistant member prevents heat generated in the busbar body from being transferred to the busbar frame. A battery module in which the thickness of the busbar body is 20% to 80% of the total thickness of the busbar.

13. A battery cell laminate in which multiple battery cells are stacked; A busbar frame formed on one or both sides of the battery cell stack; and The busbar frame includes busbars on its outer surface that are electrically connected to the electrode leads of the battery cell stack. The busbar includes a busbar body connected to the electrode lead, and a heat-resistant member interposed between the busbar and the busbar frame. The heat-resistant member prevents heat generated in the busbar body from being transferred to the busbar frame. A battery module in which the busbar includes a slit through which the electrode lead passes, and the slit is integrally formed at the same position in the busbar body and the heat-resistant member.

14. A battery pack comprising the battery module according to claim 1, 8, 10, 12, or 13.

15. An energy storage system comprising the battery pack described in claim 14.

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