KR20210049016A - Battery pack with durable property - Google Patents

Abstract

According to the present invention, disclosed is a battery pack having excellent durability. The battery pack having excellent durability according to the present invention includes: a plurality of battery cells made of a steel cylinder; and a bus bar electrically connecting electrode terminals of the battery cells. The battery pack has a flame-resistant layer disposed under the bus bar. Accordingly, the flame-resistant layer strengthens vibration resistance and at the same time improves heat dissipation, and is powdered to extinguish a fire when there is a problem in a unit battery and high heat is generated, thereby preventing the fire from spreading by adversely affecting adjacent batteries.

Description

Battery pack with durable property

The present invention relates to an excellent battery pack with excellent durability, and more particularly, to enhance vibration resistance and at the same time improve heat dissipation, and in case of high heat due to a problem in the unit battery, it is powdered to eliminate fire. It relates to a battery pack having excellent durability that can prevent a fire from spreading due to adverse effects.

Unlike primary batteries that cannot be charged normally, secondary batteries that can be charged and discharged are actively researched through the development of advanced fields such as digital cameras, cellular phones, laptop computers, power tools, electric bicycles, electric vehicles, hybrid vehicles, and large-capacity power storage devices. Is in progress.

In particular, lithium secondary batteries have a higher energy density per unit weight compared to other secondary batteries such as conventional lead storage batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and nickel-zinc batteries, and thus increase in use actively. It's going on.

Lithium secondary batteries are used as power sources for portable electronic devices with an operating voltage of 36V or higher, or for high-power electric vehicles, hybrid vehicles, power tools, electric bicycles, power storage devices, UPS, etc. by connecting multiple batteries in series or parallel. do.

Here, the cylindrical secondary battery includes an electrode assembly and an electrolyte solution, the electrode assembly includes a positive electrode plate, a negative electrode plate, and a separator, and the electrolyte solution often contains lithium ions, and the positive electrode plate and the negative electrode plate of the electrode assembly are electrode tabs drawn out to the outside. Each can be provided.

The electrode assembly is accommodated in the casing, and the electrode terminals may be exposed to the outside of the casing. The electrode tab may be drawn out of the electrode assembly to be electrically connected to the electrode terminal.

A plurality of such secondary batteries may be horizontally or vertically stacked to form a battery pack. In the secondary batteries stacked adjacent to each other in the battery pack, electrode terminals may be electrically connected to each other, and electrode terminals of neighboring secondary batteries may be connected to a bus bar, It can be electrically connected by a booth plate.

Taking Korean Patent Publication No. 2016-111457 as an example of such a battery pack, as can be seen in FIG. 7, an energy storage system includes an interconnected array of energy storage elements in which two cells are shown, and a battery They are physically fixed and held in place (eg, with a specific torque value) by a pair of opposing clamshells (upper clamshell 104 and lower clamshell 106).

For example, the clamshells have openings exposing each end of each cell. In another embodiment, the cells may be fixed by other techniques, such as a structure interleaved between the cells.

Here, the flexible printed circuit 108 places electrical terminals of the battery 102 horizontally thereon to connect, and in this embodiment, the flexible printed circuit includes a flexible lower insulating layer 112 and a flexible upper insulating layer 112 ) It includes three layers to be interposed between the flexible conductive layer 110.

The conductive layer may be a uniform metal layer such as copper, and the insulating layer may be a uniform polyimide layer (eg, a Kapton (registered trademark) material). In other embodiments, one or more other materials may be used in place of or in combination with the materials described above.

Here, the cell 102 is a kind of rechargeable battery cell having a flat top having terminals at one end, and in particular, each cell has a positive terminal 116 in the center and a negative terminal of an annular ring ( 118), for example, the annular negative terminal, which extends along the length of the cell and forms the other end of the cell (i.e., the lower end in this example). ), or can be mounted on top of it.

In the patterning of the flexible printed circuit 108, a die cut region 120 is formed on the lower insulating layer 112 so that the exposed portions of the conductive layer 110 can be electrically contacted, for example, the terminal of the battery(s). Enables selective connection to fields. Here, in the die cut region 122 of the top insulating layer 114, the exposed portion of the conductive layer 110 is a base layer (e.g., a battery ( 102) of the terminals) to form an electromechanical connection between them.

Any of a number of different types of devices and techniques can be used to make the electrical junction. For example, here by spot welding 124, portions of the conductive layer 110 are bonded to each terminal of an individual battery.

Such an energy storage system can simply be implemented as a propulsion energy source in an electric vehicle, for example. That is, in the energy storage system, a plurality of cells may be interconnected to form an array (eg, a battery pack) for operating a vehicle, and in this example, the assembly 100 is the evaporation end of the heat pipe 126 ( 126A) and the bottom of the cell 102 has an electrically insulating layer 128, which prevents electrical contact between the heat pipe (which may be a metal component) and the cell housing, for example, TIM ( thermal interface material) may be used to electrically insulate the positive terminal at the bottom of the cell while allowing cooling/heating of the cell through the same side, and in some embodiments, this assembly attaches an electrical insulating layer to the heat pipe and , It is manufactured by attaching an adhesive to the top of the layer (for example, at the location of each cell), and then positioning the cells or cells on that layer, but this structure has problems with the unit battery, It has an inherent risk of adversely affecting the battery and expanding it into a large fire.

Therefore, the technical problem to be solved by the present invention is to enhance vibration resistance and at the same time improve heat dissipation, and when there is a problem in the unit battery, it is powdered to eliminate the fire. It is to provide a battery pack with excellent durability that can be prevented from being damaged.

In order to solve the above-described technical problem, the present invention provides a battery pack comprising a plurality of battery cells made of a cylindrical shape of a steel material, and a bus bar electrically connecting electrode terminals of the battery cells, the lower portion of the bus bar It provides a battery pack having excellent fire resistance, characterized in that it has a flame-resistant layer disposed.

According to another embodiment of the present invention, the flame resistant layer may be interposed between the bus bar and the battery.

According to another embodiment of the present invention, the flame resistant layer may be provided with a through hole at a position opposite to the junction of the bus bar.

According to another embodiment of the present invention, the flame resistant layer may include silicon and mica.

According to another embodiment of the present invention, the flame resistant layer may have a thickness of 0.9 to 1.1 times the distance between the bus bar and the battery cell in order to secure adhesion.

According to another embodiment of the present invention, the flame resistant layer may have a tensile modulus of 0.1 to 1 GPa.

According to another embodiment of the present invention, the flame resistant layer may have a voltage resistance of 2.5KV to 12KV.

According to another embodiment of the present invention, the flame resistant layer may have a conductivity of 1 to 5 Watt/mK.

According to the excellent battery pack with excellent durability according to the present invention, it enhances vibration resistance and improves heat dissipation, and it is powdered to eliminate fire when high heat is generated due to a problem in the unit battery, thereby adversely affecting the adjacent battery. There is an effect that can prevent the expansion of.

1 is a photograph showing a flame resistant layer and a through hole according to the present invention,
Figure 2 is a perspective view showing a cell holder of the present invention and a view showing a latch provided on the side,
3 is a view showing an embodiment according to the bus bar of the present invention by separating the first and second bus bars,
4 is a view showing another embodiment according to the bus bar of the present invention by separating the first and second bus bars,
5 is a plan view showing a fastening hole and a nut hole provided in the terminal and the BMS holder of the present invention,
6 is a perspective view showing the battery pack according to the present invention separated and exposed for each component,
7 is a view showing a part of the side of a conventional battery pack.

Hereinafter, it should be noted that the technical terms used in the present invention are used only to describe specific embodiments, and are not intended to limit the present invention, and the technical terms used in the present invention have special different meanings in the present invention. Unless defined, the present invention should be interpreted as a generally understood meaning in the technical field to which the present invention belongs, and should not be interpreted as an excessively comprehensive or excessively reduced meaning.

In addition, when a technical term used in the present invention is an incorrect technical term that does not accurately express the spirit of the present invention, it should be replaced with a technical term that can be correctly understood by those skilled in the art.

In addition, general terms used in the present invention should be interpreted as defined in the dictionary or according to the context before and after, and should not be interpreted as an excessively reduced meaning.

In addition, the singular expression used in the present invention includes a plurality of expressions unless the context clearly indicates otherwise, for example, terms such as "consist of" or "includes" are various constituent elements described in the present invention, or It should not be construed as necessarily including all of the various steps, and some components or some steps may not be included, or additional components or steps may be further included.

Hereinafter, a battery pack for energy storage according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a photograph showing a flame-resistant layer and a through hole according to the present invention, FIG. 2 is a perspective view showing a cell holder of the present invention and a view showing a latch provided on the side, and FIG. 1 and 2 is a view showing an embodiment of the present invention by separating the first and second bus bars, Figure 4 is a view showing another embodiment according to the bus bar of the present invention by separating the first and second bus bars, and Figure 5 is a terminal of the present invention and It is a plan view showing the fastening hole and nut hole provided in the BMS holder, and FIG. 6 is a view showing a shape in which a plurality of cell holders of the present invention are applied to package battery modules of various electric capacities, and FIG. 7 is the present invention This is a perspective view showing the battery pack according to the separation and exposing each component, see this.

In the battery pack having excellent ignition resistance according to the present invention, in a battery pack including a plurality of battery cells 100 made of a cylindrical shape of a steel material, and a bus bar 200 electrically connecting electrode terminals of the battery cells, It characterized in that it comprises a flame-resistant layer 150 disposed under the bus bar.

Here, the flame-resistant layer 150 may be in close contact with and interposed between the bus bar and the battery, and may be provided with a through hole 151 at a position opposite to the junction 221 of the bus bar. It will be described later in detail.

Next, the battery pack is installed on the top of the plurality of battery cells 100, the cell holder 300 to which the battery cells 100 are connected to conduct electricity, and the plurality of cell holders 300 so that the battery cells 100 are energized. A case member 400 and a BMS holder 500 may be further included to include a bus bar 200 to cover and protect the exterior of the battery pack.

The plurality of battery cells 100 have a cylindrical shape and are installed between the plurality of cell holders 300, and the cell holder 300 has an insertion hole 330 so as to be coupled to the upper and lower portions of the battery cell 100. ) Is formed of an upper holder 310 and a lower holder 320.

In addition, in the upper holder 310 and the lower holder 320, a flat scan area is repeatedly formed so that a plurality of battery cells 100 can be joined by laser beam scanning, and protrusions and grooves are formed on the side surfaces. The upper holder 310 adjacent to each other is formed with a latch unit 340 coupled to each other, that is, the latch unit 340 allows the cell holder 300 and the cell holder 300 to be connected, and the latch unit The 340 is not formed only in the upper holder 310 and may be formed in the same manner in the lower holder 320.

One side of the upper holder 310 is provided with a protruding coupling part 350 to allow the bus bar 200 to be coupled, and the protruding coupling part 350 includes a plurality of battery cells 100 by laser beam scanning. A flat unit section (Scan area) is located between sections that are repeatedly formed so as to be bondable.

And the cell holder 300 is oriented according to the arrangement of the battery cells 100 to be accommodated in the cell holder 300 according to the size of the bus bar 200 integrally provided as a terminal of the designed voltage constituting the battery module. It is possible to ensure the expandability of the battery pack by providing the battery according to the number of cells 100.

Preferably, the battery cell 100 is formed into 16 to 20 of the insertion holes 330 of the cell holder 300 that can be used in the modularized battery module, so that the standardization of the cell holder 300 may be determined.

In addition, the cell holder 300 is not specifically limited in material as long as it can fix the battery cell 100, but in order to prevent the risk of a short circuit or a short circuit, the battery cells 100 are arranged by injection of plastic material. It can be prevented from being twisted or separated during use.

The bus bar 200 includes a first bus bar 220 and a second bus bar 210, and the first bus bar 220 and the second bus bar 210 are symmetrically disposed, and a plurality of It is characterized in that it is a battery module that is fixed by interposing two battery cells 100, wherein the first bus bar 220 is in contact with the battery cell 100 to allow high-output current to pass through, as well as dissipating heat. So it can act as a heat sink.

The first bus bar 220 has a unit conducting part 220 ′ formed at a predetermined interval to conduct electricity to the battery cell 100, and the unit conducting part 220 ′ has a junction part 221 and a plurality of It consists of a buffer leg (222).

In addition, the first bus bar 220 is preferably made of an Al material and formed to a thickness of 0.3 mm, but is not limited thereto, and may be formed to be equal to or thinner than the thickness of the second bus bar 210. , An opening into which the battery cell 100 is inserted is formed larger than the junction 221 of the unit conduction part 220', which is for the purpose of securing the area of the junction 221 and avoiding interference during beam scanning. .

The bonding portion 221 is provided to be spaced apart from the first bus bar 220 so that the electrode terminals of the battery cell 100 are bonded to conduct electricity, and the plurality of buffer legs 222 are connected to the bonding portion 221 and the first The bus bar 220 is connected.

The bonding portion 221 is preferably formed to be less than the thickness of the negative terminal of the battery cell, that is, the bonding portion 221 is disposed in contact with the electrode terminal, and the portion can be welded to enable electrical current. The positive terminal has a protrusion and a ventilation hole where the cap up is an electrode, so even if it is penetrated by high energy during laser welding, there is less risk of damage to the inside of the secondary battery, but the bottom surface of the battery cell 100, which is the negative terminal, is a battery. When damage occurs in the cell 100 material, there is a possibility that defects in the secondary battery may occur immediately, and the joint 221 performs resistance welding to prevent the occurrence of defects due to welding in advance, and in this case, resistance welding is performed. As a possible material, aluminum or copper can be used, as well as nickel or tin-coated copper.

Furthermore, it is possible to form joints and extensions through press processing by adopting nickel, nickel alloy, copper, nickel silver, iron or SPCE in the form of a plate or strip, so it has excellent workability and can occur over time. Increased contact resistance can also be prevented.In particular, the metal constituting the electrode terminal including the positive and negative terminals of the battery is often made of nickel or nickel alloy, so if the joint is made of nickel or its alloy, the welding efficiency can be increased. have.

A gas hole 223 is formed between the buffer leg 222 and the buffer leg 222, and the gas hole 223 allows gas to be discharged when the battery cell 100 is vented.

A terminal 212 is further configured on one side of the first bus bar 220, and a bolt is formed on the terminal 212 so that the BMS holder 500 can be coupled.

The second bus bar 210 has a plurality of entrance holes 211 formed at predetermined intervals so that laser bonding in a state in close contact with one side of the first bus bar 220 to be partially contacted. The second bus bar 210 is made of an Al material and has a thickness of 0.5 mm to 1 mm.

The above anti-opening property prevents the opening that can be electrically generated between the electrode terminal and the junction due to various vibrations generated during the operation of the vehicle, and can be secured by coupling or fixing with secured durability between the electrode terminal and the junction. I can.

A flame-resistant layer 150 is interposed between the bus bars 210 and 220 and the battery cell 100 in close contact with each other.

Since the battery pack having excellent ignition resistance according to the present invention is welded to the junction 221 between the battery cell and the bus bar and the electrode terminal of the battery cell, when mounted on the vehicle, any one There is a risk of damage to the welding part in places, and the flame-resistant layer 150 is in close contact between the bus bars 210 and 220 and the battery cell 100 to help absorb shock or vibration from the outside. Can be beneficial for durability.

In addition, it is beneficial to dissipate high temperature heat generated by the operation of battery cells to the outside by securing such adhesion.

Therefore, it is preferable that the flame-resistant layer 150 has a thickness of 0.9 to 1.1 times the distance between the bus bars 210 and 220 and the battery cell 100 in order to maintain adhesion, but if less than 0.9 times Heat dissipation may be reduced by reducing the portion where the flame-resistant layer contacts the bus bar or the battery cell. Conversely, if it exceeds 1.1 times, it may be helpful for adhesion, but the junction 221 and the electrode terminal of the battery cell Because welding is difficult, fairness may be reduced.

On the other hand, since the flame-resistant layer 150 must have adhesion and fairness at the same time, it is necessary to have elasticity that can contract when pressing for welding and return to its original state after welding. The tensile modulus of the flame-resistant layer is 0.1 To 1 GPa is preferable, but if it is less than 0.1 GPa, shape deformation or damage may occur during pressing for welding, whereas when it exceeds 1 GPa, it is difficult to pressurize the welding interface and thus welding defects may occur (thin film plastics Criteria for evaluating the tensile strength properties of a sheet (ASTM D882)).

In addition, the flame resistant layer 150 may include silicon or mica, and a sheet or pad may be used by mixing or respectively mixing silicon or mica.

The silicone sheet cures a composition comprising an organopolysiloxane, an organic peroxide as a curing agent, a thermally conductive filler, and a silicon compound containing at least one selected from the group consisting of an epoxy group, an alkoxy group, a methyl group, a vinyl group, and a Si-H group. It is made of silicone rubber

The thermally conductive filler may be at least one selected from the group consisting of titanium oxide, aluminum hydroxide, aluminum oxide, zinc oxide, silicon oxide, silicon carbide, aluminum nitride, boron nitride, and magnesium oxide.

In addition, the mica sheet may contain 30% by weight or more of mica powder based on the total weight of the sheet, may contain a fibrous component, and the mica powder is preferably 30 to 300 m 2 /g.

Here, as the fibrous component, aramid fiber, glass fiber, and carbon fiber may be used, and silica powder and carbon black powder may be further used as reinforcing agents.

In addition, various types of mica may be used. For example, muscovite mica or gold mica may be used, and muscovite mica is preferable for electrical insulation and gold mica is preferable for flame barriers.

As such, the flame resistant layer 150 may have a voltage resistance of about 2.5KV to 12KV, and if it is less than 2.5KV, insulation breakdown may occur due to overload due to overcurrent when the battery module malfunctions, and conversely, it exceeds 12KV. If it does, the heat dissipation characteristics are inferior.

In addition, the conductivity of the flame resistant layer 150 is preferably 1 to 5Watt/mK.If it is less than 1 Watt/mK, heat dissipation characteristics are reduced, and heat generated from the battery and heat transfer from the outside are slow, resulting in reduced heat dissipation. On the contrary, if it exceeds 5 Watt/mK, insulation characteristics may decrease due to an increase in the content of metal oxides used in the material, resulting in a decrease in withstand voltage characteristics. This can be a downside.

Battery cell 100, bus bar 200, flame resistant layer 150, junction 221, through hole 151, cell holder 300, case member 400, BMS holder 500.

Claims (8)

In the battery pack comprising a plurality of battery cells made of a cylindrical steel material, and a bus bar electrically connecting the electrode terminals of the battery cells,
A battery pack having excellent durability, comprising a flame-resistant layer disposed under the bus bar.
The method of claim 1,
The flame-resistant layer is a battery pack having excellent durability, characterized in that interposed in close contact between the bus bar and the battery.
The method of claim 2,
The flame resistant layer is a battery pack having excellent durability, characterized in that the through hole is provided at a position opposite to the junction of the bus bar.
The method of claim 1,
The flame resistant layer is a battery pack having excellent durability, characterized in that it contains silicon and mica.
The method of claim 2,
The flame-resistant layer is a battery pack having excellent durability, characterized in that it has a thickness of 0.9 to 1.1 times the distance between the bus bar and the battery cell in order to secure adhesion.
The method of claim 1,
The flame-resistant layer has excellent durability, characterized in that the tensile modulus is 0.1 to 1 GPa.
The method of claim 1,
The flame resistant layer is a battery pack having excellent durability, characterized in that it has a voltage resistance of 2.5KV to 12KV.
The method of claim 1,
The flame resistant layer is a battery pack having excellent durability, characterized in that the conductivity is 1 to 5Watt/mK.

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