KR20110008480A - Overcharge prevention device for secondary battery - Google Patents

Abstract

The present invention relates to an overcharge preventing device for a secondary battery, and an object of the present invention is to use a phenomenon in which a battery is swollen due to gas generation during overcharging in a secondary battery, thereby being damaged by a horizontal force generated between the batteries. An object of the present invention is to provide an overcharge preventing device for a secondary battery having a structure that physically shorts electricity.

The secondary battery overcharge preventing device of the present invention includes a plurality of cells 10 each including a negative electrode 1, a positive electrode 2, and an electrolyte 3, and spaced apart from each other by a predetermined distance. In the overcharge preventing device 100 for preventing overcharging of a battery, the secondary battery is formed of a plurality of cells 10 and an electrical conductor and provided on one side of the cells 10, respectively. A unit battery pack 200 including a cell connection part 20 electrically connecting them to each other; A cell crossing connector 30 provided in the unit battery pack 200 and disposed between the cells 10 and formed of an electrical conductor to electrically connect the cells 10 to each other; It is made, including, the overcharge preventing device 100 is driven by a mechanical operation mechanism, disposed between the cells 10, the cell is provided with a cross-connection connecting portion 30, the overcharge the cell ( It is characterized in that the cell cross-connection portion 30 is broken by the force generated by the volume change of 10) and electrically shorted.

Description

A Safeguard Apparatus Preventing Overcharge for A Secondary Battery}

The present invention relates to an overcharge preventing device for a secondary battery.

Batteries can be largely divided into primary and secondary batteries. Primary batteries generate electricity by using an irreversible reaction, so they cannot be reused after being used once. In this regard, a voltaic battery, and the like, and the secondary battery uses a reversible reaction, and thus, a rechargeable battery, a lithium ion battery, a Ni-Cd battery, and the like may be used as a rechargeable battery after use. Among these, NiCad batteries are generally made of nickel (Ni) oxide on the positive electrode, cadmium (Cd) compound on the negative electrode, and potassium hydroxide aqueous solution on the electrolytic solution. Was used. However, the NiCad battery has a disadvantage of a so-called memory effect, in which the charging start point is incorrectly recognized as a point where electricity is completely consumed when the battery is not fully discharged. A lithium ion battery was developed to overcome these disadvantages, and a lithium ion battery is generally made of lithium (Li) oxide on the positive electrode and carbon on the negative electrode. Lithium Ion Battery (LIB) can generate electricity with high voltage and energy density, making it possible to reduce the size and weight of the battery. Currently, it is widely used as a rechargeable battery of various portable devices such as laptops, PDAs, and mobile phones.

As described above, the lithium ion battery has a wide range of applications due to its advantages, and thus, many efforts have been made to improve the lithium ion battery. In general, a lithium ion battery refers to the use of a liquid electrolyte. A lithium ion polymer battery is made to improve stability. In the lithium ion polymer battery, a gel type polymer is a separator between a positive electrode and a negative electrode. At the same time plays a role of the electrolyte. In other words, in the lithium ion polymer battery, it is a great advantage that the solid electrolyte having excellent conductivity is basically excluded from the possibility that a liquid leakage, explosion or the like occurs when the liquid electrolyte is conventionally used. In addition, there is a lithium metal polymer battery, in which case lithium metal is used instead of carbon for the negative electrode. Table 1 below summarizes the characteristics of a lithium ion battery, a lithium ion polymer battery, and a lithium metal polymer battery.

Lithium ion battery Lithium ion polymer battery Lithium metal polymer battery cathode carbon carbon lithium Electrolyte Liquid electrolyte Polyelectrolyte Polyelectrolyte anode Metal Oxides (LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ ) Metal Oxides (LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ ) Metal Oxide, Organic Sulfur, Conductive Polymer Average voltage 3.7 V 3.7 V 2.0 to 3.6 V Energy density height height Very high Cycle characteristics Very good good Bad Low temperature characteristics good usually Bad stability Bad usually good Degree of freedom in cell design Bad good good

As shown in Table 1, it can be seen that the lithium ion polymer battery shows good overall characteristics in all characteristics, and lithium ion polymer batteries are most widely used at present.

By the way, even in the lithium ion polymer battery which improved the characteristic of a lithium ion battery, there existed a problem which was not fully solved in terms of stability. In a lithium ion polymer battery, gas is generated in the battery when an overcharge situation or the temperature of the battery rises abnormally above a certain level. The swelling of the cell occurs due to the gas generated. If this phenomenon persists, a dangerous situation may occur in which the encapsulation portion of the battery pouch is opened to release the gas or even cause a fire or explosion.

In order to solve this problem, various researches have been steadily conducted in various fields. These studies are divided into two types, a method of preventing overcharging chemically and a method of preventing overcharging electrically.

First, a technique for preventing overcharge chemically by using a composition such as a non-aqueous electrolyte, a compound that decomposes upon overcharging, as an electrolyte instead of an electrolyte currently used is disclosed in Korean Patent Registration No. 0472506 ("and polymerizable aromatics for charge prevention). Lithium Secondary Battery Containing Non-aqueous Electrolyte Containing an Additive "), Korean Patent Registration No. 0628629 (" Non-aqueous Electrolyte for Secondary Battery and Secondary Battery Containing It "), Korean Patent Publication No. 2006-0121173 (" Non-aqueous Electrolyte solution and lithium secondary battery ") and the like.

Secondly, various techniques have been disclosed to configure a circuit to block the flow of electricity when overheating, overcurrent, and overvoltage occur, or to prevent the fuse from being electrically blown (due to overheating). In Korean Patent Publication No. 2007-0010755 ("Secondary Battery Stabilization Device"), a device for interrupting charging by shorting the power supply when the charging voltage is higher than a predetermined voltage is disclosed in Korean Patent Registration No. 0729106 (" Secondary battery coupled to the safety element ") is provided with a voltage-sensing heating element and a temperature-sensitive element for generating heat above a predetermined voltage, the temperature sensitive element detects the heat generated from the heating element to reversible current An apparatus for turning ON / OFF is disclosed. In addition, Japanese Patent Laid-Open Publication No. 1993-326027 ("Charge Control Method of Secondary Battery") attaches a torsion gauge to one side of the battery, and detects a change in stress due to an increase in the internal pressure of the battery generated by charging. In other words, a device is disclosed that determines that charging is complete when the stress change reaches a certain level and stops charging. In addition, Japanese Patent Laid-Open Publication No. 199-234614 ("cylindrical battery") has a technique for improving an overcharge characteristic by automatically returning a temperature switch or a thermal fuse connected in series to a battery and a zener diode connected in parallel to the battery. In Japanese Patent No. 3778805 ("secondary battery"), an additive which generates gas above a predetermined potential in a chemical reaction occurring in the battery is added to the electrode in advance, and an opening is formed on one side of the battery by gas pressure. In addition, the present invention discloses a device that allows the gas to be generated more than the amount originally generated when an abnormality occurs in the battery due to overcharging, thereby greatly increasing the internal pressure, thereby opening the opening to discharge gas and heat to the outside. . In addition, Japanese Patent Registration No. 3622243 ("Charge and Discharge Protection Device for Secondary Battery"), Japanese Patent Registration No. 3526766 ("Function Testing Method and Function Testing Circuit of Overcharge Protection Circuit"), and Japanese Patent Publication No. 2007-028898 Various technologies for constructing a circuit for detecting an overcurrent, an overvoltage, and the like and providing the battery to a battery, such as an arc ("charge / discharge protection circuit") and Japanese Patent Laid-Open No. 2004-088878 ("assembly battery protection circuit"), are also disclosed. It is.

When looking at such conventional techniques, first, in the case of the chemical overcharge prevention method, there is a disadvantage in that the performance is lower compared to the electrolyte currently used, it is necessary to develop more. In addition, in the case of the electrical overcharge prevention method, a technique such as Japanese Patent Nos. 3622243, 3,352, 667, 2007-028898, 2004-088878, etc. should be constructed as an independent circuit and attached to the battery. Due to the increase in the number of electronic components, manufacturing is difficult and manufacturing costs increase, and there is a problem that the design cost increases due to the complicated design of the circuit. In addition, devices that cut off electricity by using overheating, overcurrent, overvoltage, etc. also use fewer components than the method of constructing an independent circuit as described above in the battery, but ultimately additional The problem described above could not be completely avoided in that the circuit was further provided in the battery.

Accordingly, the present invention has been made to solve the problems of the prior art as described above, an object of the present invention is to generate between the batteries, using the phenomenon that the battery is swollen due to gas generation during overcharge in the secondary battery The present invention provides an overcharge preventing device for a secondary battery provided with a structure that physically shorts electricity by being damaged by a horizontal force.

An overcharge preventing device for a secondary battery of the present invention for achieving the above object, a plurality of cells each comprising a negative electrode (1), a positive electrode (2) and an electrolyte (3) and are spaced a predetermined distance apart from each other An overcharge preventing device (100) for preventing overcharging of a secondary battery comprising a (10), wherein the secondary battery is formed of a plurality of cells (10) and an electrical conductor and on one side of the cells (10). A unit battery pack 200 which includes a cell connection part 20 provided at each of the cells 10 to electrically connect the cells 10 to each other; A cell crossing connector 30 provided in the unit battery pack 200 and disposed between the cells 10 and formed of an electrical conductor to electrically connect the cells 10 to each other; It is made, including, the overcharge preventing device 100 is driven by a mechanical operation mechanism, disposed between the cells 10, the cell is provided with a cross-connection connecting portion 30, the overcharge the cell ( It is characterized by breaking the cell cross-connections 30 by the force generated by the volume change of 10) to electrically short.

At this time, the overcharge preventing device 100 is connected to the cell cross-connection portion 30, the tab plate 110 is formed in the form of a plate made of an electrical conductor material; A pair of housings 120 provided in close contact with both sides of the tab plate 110 to fix the position of the tab plate 110; It is provided on the outside of the housing 120, the cutting portion 131 is formed to protrude toward the tab plate 110, so as to move toward the tab plate 110 when the volume of the cell 10 increases during overcharge A tab cutter 130 having an outer surface closely contacted with the cell 10; Characterized in that comprises a.

In addition, the overcharge preventing device 100 is provided on the outside of the housing 120, the outer surface of the holder 140 is in close contact with the cell 10; The tab cutter 130 is provided on an outer side of one side of the housing 120, and the holder 140 is provided on an outer side of the other side of the housing 120.

In addition, the tab plate 110 is characterized in that the notch or slit is formed at a position (S) corresponding to the position of the cutting portion 131 of the tab cutter (130).

In addition, the overcharge preventing device 100 includes a support unit 150 supporting the unit battery pack 200 so that the overcharge preventing device 100 is fixedly provided; And further comprising:

According to the present invention, by effectively blocking the electricity when the secondary battery is overcharged, there is a great effect that can completely eliminate the risk of fire, explosion due to gas generation, overheating, etc. generated during overcharge. In particular, since the present invention is intended to cause a short circuit due to breakage of a simple mechanical structure that utilizes a phenomenon in which the battery is swollen by a gas generated in the battery during overcharging, it is possible to reliably short-circuit electricity during overcharging so that reliability is very high. It is effective. In addition, since the mechanical structure used in the present invention only needs to be made of a structure capable of breaking the electrical (and physical) connection between the cells using the horizontal force generated by the swelling of the battery as it is, the structure There is an advantage that the design is simple and easy to manufacture, and of course, there is also an advantage that the increase in manufacturing cost is not so large.

Hereinafter, an overcharge preventing device for a secondary battery according to the present invention having the configuration as described above will be described in detail with reference to the accompanying drawings.

1 conceptually illustrates a structure of a general lithium ion battery which is one of secondary batteries. Lithium ion batteries and lithium ion polymer batteries have the same structure except that they differ only in the properties of the electrolyte (liquid / solid). In addition, depending on the battery, the material of the electrolyte or the electrode may be slightly different from the material of FIG. 1. As shown in FIG. 1, a lithium ion battery includes a cathode 1 generally made of carbon and a cathode 2 generally made of a lithium compound, an electrolyte 3 positioned between two poles 1, 2, and And a wire 4 connecting the cathode 1 and the anode 2. Lithium ions in the electrolyte 3 move toward the cathode 1 when charged and toward the anode 2 when discharged, and cause a chemical reaction by emitting or absorbing excess electrons at each pole. do. In this process, electrons flow through the wire 4, and thus electric energy is generated.

Although described using a lithium ion battery herein, other secondary batteries also have the same basic principle and structure as those used as electrodes or electrolytes. That is, the secondary battery generally includes the negative electrode 1, the positive electrode 2, the electrolyte 3, and the electric wire 4 as described above.

At this time, the secondary battery may be formed with a single negative electrode 1, a positive electrode 2, an electrolyte 3 and an electric wire 4, but more generally, a single negative electrode 1 and a positive electrode ( 2), a plurality of cells 10 consisting of the electrolyte 3 and the electric wire 4 is connected. That is, a plurality of cells 10 as described above are contained in the secondary battery pack. Of course, each cell 10 is electrically connected to each other.

Figure 2 briefly illustrates the basic concept of the overcharge protection device for a secondary battery of the present invention. The overcharge preventing device 100 for a secondary battery of the present invention includes a secondary battery as shown in FIG. 1, that is, a negative electrode 1, a positive electrode 2, and an electrolyte 3, respectively, and are spaced apart from each other by a predetermined distance. An apparatus for preventing overcharge of a secondary battery comprising a plurality of cells 10 arranged. To describe the structure of the secondary battery in more detail, the secondary battery is formed of a plurality of cells 10 and electrical conductors and provided on one side of the cells 10 to electrically connect the cells 10 to each other. A unit battery pack 200 including a cell connection unit 20 connected to each other; A cell crossing connector 30 provided in the unit battery pack 200 and disposed between the cells 10 and formed of an electrical conductor to electrically connect the cells 10 to each other; It is made, including.

At this time, the overcharge preventing device 100 of the present invention is driven by a mechanical operation mechanism, disposed between the cells 10 and provided with the cell cross-connection connecting portion 30, the cell 10 during overcharge The cell cross connection 30 is broken and electrically shorted by a force generated by a change in volume. As shown, the cell connection portion 20 is provided on the outside of the cells 10, while the cell cross-connection portion 30 is provided in a form that crosses between the cells (10). In other words, the cell connecting portion 20 and the cell cross-connection portion 30 has the same function in that the cells 10 are electrically connected, but are divided according to the form provided. At this time, the overcharge preventing device 100 of the present invention is connected to the cell cross-connection portion 30 to generate a short circuit during overcharge.

More detailed description is as follows. As described above, when the cell 10 is overcharged or the temperature of the battery is excessively high, gas is generated inside the battery, thereby expanding the volume of the cell 10. As shown in FIG. 2, the cells 10 are arranged side by side in one direction to form one unit battery pack 200, and as a result, when each of the cells 10 expands, The gap between the cells 10 is narrowed. The overcharge protection device 100 of the present invention is driven by this phenomenon, that is, a mechanical operating mechanism. The overcharge protection device 100 is provided to be connected to the cell cross-connection portion 30 that connects the cells 10 to each other physically and electrically, if the physical connection in the overcharge protection device 100 is broken ( 2, the electrical connection between the unit battery packs 200 is also apparent. The overcharge protection device 100 has a main focus here, and as the unit battery pack 200 expands to narrow the gap between the cells 10, the outer member of the overcharge protection device 100 may be formed. Pushed in so that the inner member of the overcharge protection device 100 connected to the cell cross-connection 30 is physically broken, ultimately causing the electrical short between the cells (10).

A detailed embodiment of the overcharge preventing device 100 of the present invention made on the principle described above will be described in more detail with reference to FIG. 3. Of course, the present invention is not limited by the embodiments described below, and is driven by a mechanical operation mechanism according to the principle as described above, that is, the volume change of the unit battery pack 200, and thus, between the unit battery packs 200. Any device that uses the principle of disconnecting electrical connections can be used.

As shown in FIG. 3, the overcharge preventing device 100 includes a tab plate 110, a pair of housings 120 disposed outside the tab plate 110, and an outer side of the housing 120. It comprises a tab cutter 130 provided in. In detail, each tab plate 110 is formed in the form of a plate made of an electrical conductor material, and is physically and electrically connected to the cell cross connection 30. The pair of housings 120 are provided in close contact with both sides of the tab plate 110 to fix the position of the tab plate 110. Finally, the tab cutter 130 is provided on the outside of the housing 120, the cutting portion 131 is formed to protrude toward the tab plate 110, when the volume of the cell 10 is increased during overcharging The outer surface is in close contact with the cell 10 so as to be movable toward the tab plate 110.

At this time, the overcharge preventing device 100 is provided on the outside of the housing 120, the outer surface of the holder 140 is in close contact with the cell 10; It may be made to include more. That is, when the overcharge preventing device 100 does not include the holder 140, the tap cutter 130 may be disposed outside the pair of the housing 120 (as shown in FIG. 2). A pair is provided, respectively, when the overcharge protection device 100 includes the holder 140, the tab cutter 130 is provided on the outer side of one side of the housing 120, of the housing 120 The outer side of the other side is provided with the holder 140.

4 shows an operation example of the overcharge preventing device 100. As shown in FIG. 4 (A), the overcharge preventing device 100 has the housing 120-the tab cutter 130 (or the holder) around the tab plate 110 in both outward directions. 140 is disposed between the cells 10. That is, the tab cutter 130 or the holder 140 is connected to the cells 10 in the unit battery pack 200. In the state where the unit battery pack 200 is normally operated (that is, the unit battery pack 200 is not expanded), the tap cutter 130 or the holder 140 It is not necessary that the cell 10 is in close contact with the cell 10 in the unit battery pack 200, and of course, the tab cutter 130 or the holder 140 may be moved to the cell 10 in the unit battery pack 200. It may be arranged in close contact with the) or provided with a fixed. FIG. 4 illustrates a case in which the overcharge preventing device 100 includes both the tab cutter 130 and the holder 140. Hereinafter, the holder 140 is not included. Even if not, the overcharge preventing device 100 of the present invention operates by the same principle as the following description, but it is to be understood that another tap cutter 130 is disposed in the position of the holder 140 of FIG. .

At this time, when the unit battery pack 200 is expanded, the tab cutter 130 and the holder 140 are pushed by the cell 10 in the unit battery pack 200, as shown in FIG. 4B. As it is pushed toward the tab plate 110. In this case, since the cutting portion 131 is protruded toward the tab plate 110 in the tab cutter 130, the cutting portion 131 is pushed toward the tab plate. Closer to the tab plate 110, and finally, the cutting part 131 proceeds to a position where the cutting part 131 is better than the tab plate 110, whereby the tab plate 110 is cut to the cutting part ( 131).

As described above, the tab plate 110 is connected to the cell cross-connections 30 provided across the cells 10 in the unit battery pack 200 to form an electrical connection between the cells 10. It is. Therefore, when the tab plate 110 is cut, the electrical connection between the cells 10 in the unit battery pack 200 is cut off, and thus, no electricity flows to the unit battery pack 200, thereby no further charging. This is not done so that it is possible to prevent damage to the unit battery pack 200 due to overcharge. As described above, the overcharge preventing apparatus 100 of the present invention utilizes a phenomenon in which the unit battery pack 200 expands during overcharging, so that an electrical short circuit is performed using a very simple mechanical structure. That is, the overcharge preventing device 100 of the present invention does not require any separate power source, and thus is not only excellent in terms of energy efficiency, but also its structure is very simple, and the difficulty of designing, manufacturing and assembling is very low. There is a big advantage that can greatly save.

In FIG. 3 and FIG. 4, the overcharge preventing device 100 is illustrated in which the tab cutter 130 is disposed at one side of the tab plate 110 and the holder 140 is disposed at the other side. As shown in FIG. 2, the overcharge preventing device 100 may be configured in a form in which the tab cutter 130 is disposed on both sides of the tab plate 110. In both cases, the principle that the tab plate 110 is finally cut by being pushed in by the expansion of the unit battery pack 200 during overcharge causes an electrical short circuit. The holder 140 may be formed in substantially the same shape as the tab cutter 130, but in a form in which the cutting part 131 is deleted, and the tab cutter 130 may be formed according to the presence or absence of the holder 140. Only the projecting degree of the cutting unit 131 may be adjusted and designed. That is, when the overcharge preventing device 100 is formed in a shape in which the tab cutter 130 is formed at one side of the tab plate 110 and the holder 140 is arranged at the other side, the cutting part 131 Since one), the cutting unit 131 may be formed to protrude more. In addition, when the overcharge preventing device 100 is formed in a form in which the tab cutter 130 is disposed on both sides of the tab plate 110, the cutting parts 131 are formed on both sides of the tab plate 110. Since it is pushed in, the cutting portion 131 is made shorter than when the holder 140 is included in the overcharge preventing device 100 may be formed to meet each other at the position of the tab plate 110. Alternatively, the tab cutter 130 may be disposed on both sides of the tab plate 110 so that the tab plate 110 is more surely cut, and the cutting parts 131 do not meet each other. By forming, that is, the tab plate 110 may be formed to be cut in two places.

As shown in FIG. 3, the tab plate 110 may have a notch or a slit formed at a position S corresponding to the position of the cutting portion 131 of the tab cutter 130. When a notch or slit is formed in the tab plate 110, the tab plate 110 may be more easily cut by advancing the cutting part 131.

In addition, the overcharge preventing device 100 includes a support unit 150 supporting the unit battery pack 200 so that the overcharge preventing device 100 is fixedly provided; It may be made to include more. FIG. 5 illustrates an installation example in which the supporting unit 150 is fixed to an outer housing of the unit battery pack 200. In FIGS. 3 and 4, the supporting unit 150 includes the tab plate 110. It is shown a structure that is connected to. According to the supporting part 150, the overcharge preventing device 100 may be more stably provided between the unit battery packs 200.

The present invention is not limited to the above-described embodiments, and the scope of application of the present invention is not limited to those of ordinary skill in the art to which the present invention pertains without departing from the gist of the present invention as claimed in the claims. Of course, various modifications can be made.

1 is a structural diagram of a typical lithium ion battery.

2 is a principle of the overcharge preventing device of the present invention.

Figure 3 is an embodiment of the overcharge protection device of the present invention.

Figure 4 is an operation example of the overcharge protection device of the present invention.

Figure 5 is an installation example of the overcharge protection device of the present invention.

DESCRIPTION OF REFERENCE NUMERALS

1: cathode 2: anode

3: electrolyte 4: wire

200: unit battery pack 10: cell

20: cell connection 30: cell cross connection

100: overcharge prevention device (of the present invention)

110: tab plate 120: housing

130: tap cutter 131: cutting portion

140: holder 150: supporting part

Claims (5)

An overcharge preventing device 100 including an anode 1, an anode 2, and an electrolyte 3, respectively, and including a plurality of cells 10 spaced apart from each other by a predetermined distance, to prevent overcharging of a secondary battery 100. ), The secondary battery includes a plurality of cells 10 and cell connectors 20 formed of electrical conductors and provided on one side of the cells 10 to electrically connect the cells 10 to each other. A unit battery pack 200; A cell crossing connector 30 provided in the unit battery pack 200 and disposed between the cells 10 and formed of an electrical conductor to electrically connect the cells 10 to each other; Including, The overcharge preventing device 100 is driven by a mechanical actuation mechanism, is disposed between the cells 10 and is connected to the cell cross connection 30, and the overcharge charging device 100 may change the volume of the cell 10 during overcharge. Overcharge preventing device for a secondary battery, characterized in that by the force generated by the cell cross-connection (30) is broken and electrically shorted. According to claim 1, wherein the overcharge preventing device 100 A tab plate 110 connected to the cell cross connection part 30 and formed in a plate shape made of an electrical conductor material; A pair of housings 120 provided in close contact with both sides of the tab plate 110 to fix the position of the tab plate 110; It is provided on the outside of the housing 120, the cutting portion 131 is formed to protrude toward the tab plate 110, so as to move toward the tab plate 110 when the volume of the cell 10 increases during overcharge A tab cutter 130 having an outer surface closely contacted with the cell 10; Overcharge protection device for a secondary battery, characterized in that comprises a. The method of claim 2, wherein the overcharge preventing device 100 A holder 140 provided on an outer side of the housing 120 and having an outer surface closely contacted with the cell 10; It is made to include more The tab cutter 130 is provided on the outer side of one side of the housing 120, the holder 140 is provided on the outer side of the other side of the housing (120). The method of claim 2, wherein the tab plate 110 is Notch or slit is formed at a position (S) corresponding to the position of the cutting portion 131 of the tab cutter 130, overcharge protection device for a secondary battery. The method of claim 2, wherein the overcharge preventing device 100 A support unit 150 supporting the unit battery pack 200 so that the overcharge preventing device 100 is fixedly provided; Overcharge protection device for a secondary battery, characterized in that further comprises.

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