KR102616790B1 - Fire safety battery pack - Google Patents

Abstract

The battery pack includes a housing including an internal accommodating space and a through hole communicating from the accommodating space to the outside; It includes a battery cell including a receiving portion accommodated in the receiving space of the housing and an exposed portion exposed to the outside of the housing through a through hole and provided with electrodes for inputting and outputting current; The receiving space of the housing is filled with a fire-retardant material that has fire extinguishing and cooling properties and is capable of contacting the receiving portion of the received battery cell.

Description

Fire safety battery pack {FIRE SAFETY BATTERY PACK}

The present invention relates to a battery pack including a plurality of battery cells, and more specifically, to a battery pack with a structure that blocks fire caused by heat generated from the battery cells or prevents the spread of fire.

Batteries convert chemical energy into electricity, store it, produce direct current power, and supply power to electronic devices that operate on electricity. Batteries include primary batteries (alkaline batteries, mercury batteries, lithium batteries, etc.) that cannot be recharged once all of the electricity stored inside them has been consumed, and secondary batteries that can be recharged and used (nickel-cadmium batteries, nickel-cadmium batteries, etc.) It is divided into hydrogen battery, lithium-ion battery, lithium-ion polymer battery, etc.). The individual unit of a battery is referred to as a cell. Here, in order to meet the power characteristics (voltage, capacity, power density, etc.) required for electronic devices, a combination of battery cells can be prepared by connecting a plurality of battery cells in series or parallel, which can be used as a battery module or It is referred to as a battery pack.

Due to the nature of batteries that contain a combination of various chemicals, there is a possibility that fire or thermal explosion may occur due to heat generation. In particular, in the case of a battery pack including a plurality of battery cells, a fire occurring in one battery cell may spread to adjacent battery cells, resulting in a chain reaction of fire or thermal explosion.

Therefore, when operating a battery pack containing a plurality of battery cells, each battery may be damaged due to internal causes (such as heat generated by the battery cell itself) or external causes (such as shock or heat applied to the battery cell from the outside). It is very important to create an environment that prevents explosions and heat generation from cells.

The present invention was created in consideration of the above problems, and prevents heat generated from each battery cell from developing into a fire or thermal explosion, extinguishes a fire occurring in one battery cell, and prevents the fire from spreading to adjacent battery cells. The purpose is to provide a battery pack that can prevent this.

In order to achieve the above object, a battery pack according to an embodiment of the present invention includes a housing including an internal accommodating space and a through hole communicating from the accommodating space to the outside, an accommodating part accommodated in the accommodating space of the housing, and A battery cell is exposed to the outside of the housing through the through hole and includes an exposed portion provided with an electrode for inputting and outputting current, and in the receiving space of the housing, an accommodating portion of the received battery cell having fire extinguishing and cooling properties. It is filled with fire retardant material so that it can come into contact with. As a result, the fire protection characteristics of the battery pack can be improved.

Additionally, a plurality of battery cells may be provided, and a plurality of through holes may be arranged to be spaced apart from each other in the housing to accommodate the plurality of battery cells, respectively. As a result, the spread of fire between battery cells can be suppressed by filling the battery cells with fire-retardant material.

Additionally, it may include a conductive strap that electrically connects the electrodes of each of the plurality of battery cells. As a result, it is possible to output the power required for the battery pack.

Additionally, the strap opens the electrode to be connected to the electrode, and may include a non-conductive bracket coupled to the housing to cover the exposed portion of the battery cell. As a result, it is possible to connect the electrodes without the strap contacting the fire retardant material.

Additionally, the fire retardant may include a high molecular weight polymer based on a water-soluble polymer. Thereby, the fire retardant properties of the fire retardant material can be guaranteed.

According to the present invention, it is possible to provide a battery pack that can cope with fire, thermal explosion, etc. with a simple structure.

1 is an exploded perspective view of a housing of a battery pack according to an embodiment of the present invention.
Figure 2 is a perspective view showing a housing in which a battery cell is accommodated according to an embodiment of the present invention.
Figure 3 is a perspective view of a battery pack containing battery cells according to an embodiment of the present invention.
Figure 4 is a graph showing temperature change in a test using a battery pack according to an embodiment of the present invention.
Figure 5 is a graph showing temperature changes in another test using a battery pack according to an embodiment of the present invention.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Embodiments described with reference to each drawing are not mutually exclusive unless otherwise noted, and a plurality of embodiments may be selectively combined and implemented within one device. A combination of these plural embodiments may be arbitrarily selected and applied by a person skilled in the art of the present invention when implementing the spirit of the present invention.

If there are terms including ordinal numbers, such as first component, second component, etc. in the embodiment, these terms are used to describe various components, and the term distinguishes one component from other components. As used for this purpose, the meaning of these components is not limited by the terms. Terms used in the examples are applied to describe the corresponding example and do not limit the spirit of the present invention.

In addition, when the expression "at least one" appears among a plurality of components in this specification, this expression refers to not only all of the plurality of components, but also each one of the plurality of components excluding the rest. It refers to all combinations of .

1 is an exploded perspective view of a housing of a battery pack according to an embodiment of the present invention.

Figure 2 is a perspective view showing a housing in which a battery cell is accommodated according to an embodiment of the present invention.

Figure 3 is a perspective view of a battery pack containing battery cells according to an embodiment of the present invention.

As shown in FIGS. 1 to 3, the battery module 1 or battery pack 1 according to an embodiment of the present invention includes a plurality of battery cells 100 provided to supply power as designed in advance, It includes a housing 200 that accommodates a plurality of battery cells 100. The power value output from the battery pack 1 is determined based on the combination of the current output from each of the plurality of battery cells 100, and each battery cell 100 is connected in series or in parallel. Depending on this, the final output power value varies.

The battery cell 100 applied to the battery pack 1 may be a non-rechargeable primary battery or a rechargeable secondary battery. If the battery cell 100 is a secondary battery, although not shown, the battery pack 1 may additionally include adapter equipment for charging. The battery cell 100 in this embodiment has a cylindrical shape with a circular cross-section in the horizontal direction, but the shape of the battery cell 100 is not limited to this example. For example, the horizontal cross-section of the battery cell 100 may have various polygonal shapes, such as a square. The battery cell 100 includes electrodes 110 for inputting and outputting current. The position of the electrode 110 is not limited, and for example, two electrodes 110 (+) and (-) may be provided on one end of the battery cell 100, or on one end of the battery cell 100. A (+) electrode 110 may be provided and a (-) electrode 110 may be provided at the other end.

The housing 200 forms an accommodating space therein for accommodating the battery cell 100. Although the housing 200 has an overall hexahedral shape, the shape of the housing 200 is not limited to this example. The housing 200 may be made of any material, but is preferably made of plastic or metal with heat-resistant properties.

The housing 200 includes a side wall 210, a top plate 220 coupled to the side wall 210 to cover the upper opening of the side wall 210, and a top plate 220 coupled to the side wall 210 to cover the lower opening of the side wall 210. It includes a lower plate 230. The side wall 210 extends up and down along the longitudinal direction. The upper plate 220 and the lower plate 230 extend along the horizontal direction so as to be perpendicular to the side wall 210. Here, the vertical length of the side wall 210 is shorter than the length of the battery cell 100, and the reason for this will be described later.

The side wall 210, upper plate 220, and lower plate 230 are preferably made of the same material in consideration of ease of joining process and productivity, but may be made of different materials depending on the purpose (e.g., battery pack (1) Depending on the installation location, a material with higher rigidity and heat resistance can be applied to any one of the side wall 210, upper plate 220, and lower plate 230).

The upper plate 220 and the lower plate 230 may be coupled to the side wall 210 in various ways. As an example, they may be permanently coupled during the manufacturing step of the housing 200. When the housing 200 is made of plastic, the upper plate 220 and the lower plate 230 may be joined to the side wall 210 using a melt adhesive method. When the housing 200 is made of metal, the upper plate 220 and the lower plate 230 may be joined to the side wall 210 by welding. Alternatively, the upper plate 220 and the lower plate 230 may be detachably coupled to the side wall 210. For example, the shape of each corner of the upper plate 220 and the lower plate 230 is provided to correspond to the shape of the corner of the side wall 210 forming the upper or lower opening, so that the upper plate 220 and the lower plate ( 230 may be fitted into the side wall 210 (for example, steps are provided on each of the side wall 210 and the top plate 220, and these steps engage with each other). Alternatively, the upper plate 220 and the lower plate 230 may be coupled to the side wall 210 using a fastening method such as screws.

The upper plate 220 includes one or more upper receiving holes 221. When the battery pack 1 includes a single battery cell 100, one upper receiving hole 221 may be provided in the upper plate 220. In the case of this embodiment, since the battery pack 1 includes a plurality of battery cells 100, the top plate 220 is provided with the same number of upper receiving holes 221 as the number of battery cells 100 ( 6 in this example).

Since the upper receiving hole 221 provides a passage through which the battery cell 100 enters the inside of the housing 200, the diameter of the upper receiving hole 221 is that of the battery cell 100 accommodated in the upper receiving hole 221. It is prepared to correspond to the width. However, when assembling the battery pack 1, the battery cell 100 does not necessarily have to enter through the upper receiving hole 221. For example, after inserting the battery cell 100 into the side wall 210, the battery cell 100 A process such as covering the upper plate 220 on the upper part of the cell 100 so that it comes out through the upper receiving hole 221 is also possible.

In this embodiment, the case where the diameters of each of the plurality of upper receiving holes 221 are the same is shown. However, when battery cells 100 of different specifications or sizes are applied to the battery pack 1, the plurality of upper receiving holes 221 have the same diameter. The receiving holes 221 also have different diameters. If the diameter of the upper receiving hole 221 is the same as the width of the battery cell 100, it is difficult for the battery cell 100 to be accommodated through the upper receiving hole 221, so the diameter of the upper receiving hole 221 is the same as the width of the battery cell 100. 100) is provided to be larger than the width by a predetermined length. Here, the above-mentioned length may be determined to various values during the manufacturing process within a range in which the battery cell 100 accommodated in the housing 200 does not significantly flow in the horizontal direction.

The upper plate 220 includes a sealing portion 222 provided around the upper receiving hole 221. The sealing portion 222 includes a step or groove formed in an area of the upper plate 220 that forms the upper receiving hole 221. After the battery cell 100 is accommodated in the housing 200, a sealing material is applied along the sealing portion 222 to maintain the airtightness of the accommodating space inside the housing 200. The sealing material is first applied to the sealing portion 222 in a gel or gel state and then cured. The type of sealing material is not limited and may be, for example, silicone-based, polysulfide-based, polyurethane-based, acrylic-based, etc.

The upper plate 220 includes a fire retardant injection port 223 formed through the fire retardant material for injecting the fire retardant material. The fire retardant injection port 223 is a passage through which fire retardant material is injected into the receiving space of the housing 200, and is sealed with a sealing material, stopper, screw, etc. after the injection of the fire retardant material is completed.

In this embodiment, a case where the structure of the lower plate 230 is generally the same as that of the upper plate 220 will be described. In this case, the lower plate 230 includes a lower receiving hole 231 that plays the same role as the upper receiving hole 221 of the upper plate 220, and the sealing method is also the same as that of the sealing portion 222 of the upper plate 220. It is applied properly. However, the lower plate 230 does not include a component corresponding to the fire retardant material inlet 223 of the upper plate 220. The battery cell 100 penetrates the upper receiving hole 221 of the upper plate 220 and the lower receiving hole 231 of the lower plate 230. In this case, the central part of the battery cell 100 is accommodated in the receiving space of the housing 200, the upper end of the battery cell 100 is exposed to the outside from the upper receiving hole 221 of the top plate 220, and the battery cell ( The lower end of 100) is exposed to the outside from the lower receiving hole 231 of the lower plate 230. Accordingly, the portion of the battery cell 100 accommodated in the receiving space of the housing 200 is referred to as the receiving portion (in this example, the central portion of the battery cell 100), and the battery cell 100 is provided with receiving holes 221 and 231. The portion exposed to the outside through may be referred to as an exposed portion (in this example, the upper and lower portions of the battery cell 100), respectively, for convenience.

Meanwhile, depending on the design method, the lower plate 230 may not include the lower receiving hole 231, because the (+) and (-) electrodes 110 are located at the upper end of the battery cell 100. In this case, the lower end of the battery cell 100 does not need to be exposed to the outside of the housing 200. In this case, the receiving portion corresponds to the central and lower portions of the battery cell 100, and the exposed portion corresponds to the upper portion of the battery cell 100.

When the plurality of battery cells 100 are accommodated in the receiving space of the housing 200 through the upper receiving hole 221 and the lower receiving hole 231 and then sealed, the receiving space is excluding the fire retardant material inlet 223. This ensures confidentiality to the outside world. In this state, if the fire retardant material is injected through the fire retardant material inlet 223 and the fire retardant material inlet 223 is sealed, the fire retardant material stored in the accommodation space does not leak out of the housing 200. The fire retardant material stored in the receiving space can more efficiently deal with heat, fire, etc. that may occur in the battery cell 100 by directly contacting the battery cell 100.

Fire retardants can include a variety of substances that primarily have fire extinguishing and cooling properties. The properties required for fire retardant materials are diverse, for example, to extinguish a fire occurring in a battery cell 100 and prevent it from spreading to an adjacent battery cell 100, or to prevent the heat generated in a battery cell 100 from developing into a fire. Before being delivered, characteristics such as transmission to the outside of the housing 200 are considered.

For example, fire retardants include polymers based on water-soluble polymers. Fire retardant materials contain cross-linked polymers, and an aqueous solution is contained in the empty spaces of the network structure of the polymers. High molecular weight polymers form crosslinks between multiple polymer chains and crosslinking molecules, thereby forming a network structure. If a fire occurs in the battery cell 100, some of the aqueous solution in the network structure within the high molecular weight polymer of the fire retardant evaporates due to the heat of the fire. As the aqueous solution evaporates, the polymer chains on the side closest to the fire cover the area where the fire occurs, blocking oxygen. The remaining aqueous solution remaining in the polymer moves toward the polymer chain covering the fire occurrence area, suppressing combustion of the polymer chain and lowering the temperature of the fire. Finally, when all of the aqueous solution in the polymer polymer is evaporated, the fire is extinguished, and the polymer polymer is coated in the form of a coating on the fire occurrence area of the battery cell 100. In this way, extinguishment by fire retardant is possible.

Alternatively, the fire retardant may include powdered fire extinguishing agent. Powdered fire extinguishing agents are capable of blocking and cooling external oxygen due to their high weight and have a high melting point, so they are easier to be adsorbed to the surface of combustion products compared to high molecular weight polymers. Through this, it melts at a high temperature and forms a film on the combustion product, thereby blocking oxygen. Powdered fire extinguishing agents may include, for example, fumed silica powder, vermiculite powder, expanded glass powder, or sodium chloride (NaCl) powder.

Alternatively, the fire retardant material may further include a thermally conductive material. Thermal conductive materials are advantageous in reducing temperature by increasing the thermal conductivity of fire retardant materials. The thermally conductive material may include, for example, graphite or sodium chloride.

Alternatively, the fire retardant may include an additive including any one or more of a cross-linking agent, an activator, a moisture evaporation inhibitor, and a propellant. The crosslinking agent reduces the scale of explosion when extinguishing a fire and at the same time fixes the polymer, and may include, for example, boric acid or borax. The activator promotes the crosslinking role of the crosslinking agent and may include, for example, sodium bicarbonate. Moisture evaporation inhibitors inhibit the evaporation of aqueous solutions (distilled water, salt water, or saline solution) and may include, for example, glycerin. The propellant is intended to spray fire retardant materials in the form of foam, and may include, for example, inert substances such as argon and nitrogen.

Meanwhile, the battery pack 1 includes a bracket 300 coupled to the housing 200 to cover the exposed portion of the battery cell 100. However, depending on the design method, the battery pack 1 may not include the bracket 300. In this embodiment, the bracket 300 includes an upper bracket 310 that covers the upper end of the battery cell 100, and a lower bracket 320 that covers the lower end of the battery cell 100. For ease of production, the upper bracket 310 and lower bracket 320 may have the same structure. However, the (+) and (-) electrodes 110 are at the upper end of the battery cell 100, and the lower plate 230 has a structure that does not include the lower receiving hole 231 (i.e., the lower end of the battery cell 100). In the case of a structure in which the accommodation space of the housing 200 is accommodated, the lower bracket 320 may not be provided.

When coupled to the housing 200, the upper bracket 310 includes an electrode opening 311 that exposes the electrode 110 provided at the upper end of the battery cell 100 to the outside. Additionally, the battery pack 1 includes one or more straps 330 that electrically connect electrodes provided in each of the plurality of battery cells 100. The strap 330 is not limited as long as it is made of a conductive material, and includes metals such as nickel, copper, and aluminum, for example. The strap 330 connects the electrodes exposed through the electrode opening 311. The upper bracket 310 is made of a non-conductive material such as plastic or polymer, so that even if the strap 330 contacts the electrode opening 311, there are no electrical problems such as electrical leakage. In this embodiment, only the case where the strap 330 is provided at the upper end of the battery cell 100 is shown. However, even when the electrode 110 is provided at the lower end of the battery cell 100, the strap 330 can be installed in the same way. You can.

Hereinafter, the process of manufacturing the battery pack 1 will be described.

The housing 200 is manufactured by combining the side wall 210, the upper plate 220, and the lower plate 230. After the plurality of battery cells 100 enter the inside of the housing 200 through the upper receiving hole 221, or the plurality of battery cells 100 are accommodated in the side wall 210 of the housing 200, the upper plate 220 or A plurality of battery cells 100 are accommodated in the housing 200 according to the manner in which the lower plate 230 is covered. In a state where the receiving portion of the battery cell 100 is accommodated in the receiving space of the housing 200 and the exposed portion of the battery cell 100 is exposed to the outside of the upper receiving hole 221 and the lower receiving hole 231, the upper receiving hole Sealing is performed on the sealing portion 222 of each of the 221 and lower receiving holes 231. The fire retardant material is injected through the fire retardant injection port 223, and the accommodating space between each receiving portion of the plurality of battery cells 100 in the housing 200 is filled with the retardant material. After the fire retardant material is filled in the receiving space, the fire retardant material inlet 223 is sealed.

The upper bracket 310 and the lower bracket 320 are coupled to the housing 200 to cover the exposed portion of the battery cell 100. The electrode 110 of each battery cell 100, which is open to the outside through the electrode opening 311, is connected by the strap 330, thereby realizing the power characteristics required for the battery pack 1. In addition, the battery pack 1 of this embodiment does not require sealing of the electrodes 110 using a method such as epoxy molding, compared to a battery pack with an immersion structure in which the entire battery cell 100 is immersed in a conductive fire-retardant material. does not exist. Since this sealing process requires a long drying time, the process time is excessively long, and the sealing of the electrode 110 is vulnerable to physical shock. Accordingly, the battery pack 1 of this embodiment is relatively easy to manufacture and reduce cost, and is lighter and more resistant to shock.

According to this process, a battery pack 1 is provided that can cope with disasters such as fire and thermal explosion due to heat generated from the battery cell 100 through a simple structure.

Hereinafter, a test for determining the effect of suppressing temperature rise of the battery pack 1 according to this embodiment will be described.

Figure 4 is a graph showing temperature change in a test using a battery pack according to an embodiment of the present invention.

As shown in FIG. 4, a first case equipped with a typical battery pack and a second case equipped with a battery pack 1 according to this embodiment are installed on the same traveling device (for example, a kickboard). The temperature can be measured separately. For example, if the motor is driven in each case for 30 minutes in a room at 21 degrees Celsius and the cooling performance is measured for 40 minutes after the motor is stopped, a graph as shown in FIG. 4 can be derived. The horizontal axis of the graph is time in minutes, and the vertical axis of the graph is temperature in degrees Celsius. In the graph, the red curve represents the first case and the blue curve represents the second case. Since measurements were made 5 times for each case, a total of 10 curves are shown on the graph.

In the first case, the average of the highest temperature of five measurements was 24.8 degrees, and the temperature deviation between the battery cells 100 was 1.6 degrees. In comparison, in the second case, the average of the highest temperature of the five measurements was 22.6 degrees, and the temperature deviation between the battery cells 100 was 0.3 degrees. Accordingly, it can be confirmed that the second case is superior to the first case in suppressing high temperature rise and cooling performance.

Figure 5 is a graph showing temperature changes in another test using a battery pack according to an embodiment of the present invention.

As shown in FIG. 5, the actual running of the traveling device can be performed and the temperature can be measured for each of the first and second cases. The left graph of FIG. 5 shows the temperature change while the traveling device is running, and the right graph shows the temperature change after the traveling device has finished traveling. Driving conditions are approximately 100 meters at an outdoor temperature of 30 degrees Celsius. The average value can be derived by testing multiple times for each case.

In the first case, the average maximum temperature during driving was 39 degrees, the average maximum temperature after driving was 45.9 degrees, and the temperature difference between battery cells 100 was 6 degrees. In comparison, in the second case, the average maximum temperature during driving was 28.4 degrees, the average maximum temperature after driving was 30.9 degrees, and the temperature difference between battery cells 100 was 0.5 degrees. The test in Figure 5 was conducted under harsher conditions than the test in Case 4, and the characteristics of the second case were significantly improved compared to the first case. Through these tests, it can be seen that the temperature characteristics of the battery pack 1 of this embodiment are improved.

1: Battery pack
100: battery cell
110: electrode
200: housing
300: bracket
311: electrode opening
330: strap

Claims (5)

In the battery pack,
A housing in the shape of a hexahedron including an upper plate, a lower plate, and side walls, and having an accommodating space therein,
The upper plate communicates with the outside from the receiving space and has a plurality of upper receiving holes spaced apart from each other, and the lower plate communicates with the outside from the receiving space and has a plurality of lower receiving holes spaced from each other,
A fire retardant material having fire extinguishing and cooling properties and accommodated in the receiving space of the housing,
An accommodating part accommodated in the accommodating space of the housing and in contact with the fire retardant material, and an upper exposed part extending from the accommodating part and exposed to the outside of the housing through the upper accommodating hole and provided with a first electrode for inputting and outputting current. and a plurality of battery cells each including a lower exposed portion extending from the receiving portion and exposed to the outside of the housing through the lower receiving hole and provided with a second electrode having an opposite polarity to the first electrode;
A sealing material that seals the plurality of upper accommodating holes and the plurality of lower accommodating holes, respectively, so that the fire retardant material in the accommodating space does not contact the upper exposed portion and the lower exposed portion of each of the plurality of battery cells;
At least one conductive first strap electrically connecting the plurality of first electrodes exposed to the outside of the housing,
A battery pack including one or more conductive second straps electrically connecting the plurality of second electrodes exposed to the outside of the housing. delete delete According to paragraph 1,
a non-conductive upper bracket coupled to the housing to open the plurality of first electrodes so that the first strap is connected to the plurality of first electrodes, and to cover the upper exposed portion of each of the plurality of battery cells;
The second strap opens the plurality of second electrodes to be connected to the plurality of second electrodes, and includes a non-conductive lower bracket coupled to the housing to cover the lower exposed portion of each of the plurality of battery cells. Battery pack. According to paragraph 1,
The fire retardant material is a battery pack containing a polymer based on a water-soluble polymer.

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