Battery for short-circuit inspection, method for manufacturing the same, and method for analyzing battery safety

Abstract

The present invention relates to a battery for short circuit testing, a manufacturing method thereof, and a method for analyzing the safety of the battery, and provides a battery for short circuit testing that can be easily switched to an internal short circuit state and analyzes the safety of the battery through the battery, a manufacturing method thereof, and a method for analyzing the safety of the battery.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0163887, filed on Nov. 25, 2021, and all contents disclosed in the literature of the Korean Patent Application are incorporated herein by reference.

[0002] The present invention relates to a battery for short-circuit inspection, a method for manufacturing the same, and a method for analyzing the safety of a battery, and more particularly, to a battery for short-circuit inspection that can be easily switched to an internal short-circuit state, a method for manufacturing the same, and a method for analyzing the safety of a battery through the battery.

Background Art

[0003] Generally, a secondary battery is a battery that can be repeatedly used through a discharge process of converting chemical energy into electrical energy and a charging process in the reverse direction. Secondary batteries with high applicability to product groups and electrical characteristics such as high energy density are widely applied not only to portable devices but also to electric vehicles (EVs) or hybrid vehicles (HVs) driven by an electric drive source.

[0004] As secondary batteries are applied to various products, the safety of secondary batteries is linked to the safety of the products, and thus the evaluation of the safety of secondary batteries is important.

[0005] There are various evaluations of the safety of secondary batteries, and one of them is an internal short-circuit inspection in which the negative electrode and the positive electrode are in contact inside the secondary battery.

[0006] Secondary batteries may be short-circuited by various internal and external environments, and there is a risk of ignition during short-circuit.

[0007] Therefore, there is a need for a technology that can easily apply a short-circuit state to a secondary battery and analyze the safety of the secondary battery in the short-circuit state.

Summary of the Invention

Problems to be Solved by the Invention

[0008] The present invention relates to a battery for short - circuit inspection, a method for manufacturing the same, and a method for analyzing the safety of a battery. It is to provide a battery for short - circuit inspection that can be easily switched to an internal short - circuit state, a method for manufacturing the same, and a method for analyzing the safety of a battery by analyzing the safety of the battery through the battery.

[0009] The technical problems to be solved by the present invention are not limited to the above - mentioned technical problems. Further other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

Means for Solving the Problems

[0010] The battery for short - circuit inspection of the present invention includes: a positive electrode part formed by applying a positive electrode active material to a positive electrode current collector; a negative electrode part formed by applying a negative electrode active material to a negative electrode current collector; a perforated separator laminated between the positive electrode part and the negative electrode part, in which perforated holes are formed; an auxiliary separator covering the perforated holes laminated between the positive electrode part and the negative electrode part; and a battery case for housing the positive electrode part, the negative electrode part, the perforated separator, and the auxiliary separator inside. In the positive electrode part, an active material removal region where the positive electrode active material is removed is formed in a region facing the perforated holes of the perforated separator.

Effects of the Invention

[0011] The battery for short - circuit inspection of the present invention can arbitrarily impart a short - circuit state to a secondary battery under a desired situation. It can analyze the safety of a secondary battery by imparting a short - circuit state to the secondary battery under various conditions such as different SOCs, temperatures, and impacts.

[0012] The method for analyzing the safety of a battery of the present invention can simulate the driving situation of a product to which a secondary battery is applied, impart a short - circuit state, and analyze the safety of the secondary battery.

[0013] The battery safety analysis method of the present invention can easily confirm the presence or absence of battery safety.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0015] The battery for short-circuit inspection of the present invention includes a positive electrode portion formed by applying a positive electrode active material to a positive electrode current collector; a negative electrode portion formed by applying a negative electrode active material to a negative electrode current collector; a perforated separator laminated between the positive electrode portion and the negative electrode portion and having perforated holes formed therein; an auxiliary separator covering the perforated holes laminated between the positive electrode portion and the negative electrode portion; and a battery case for housing the positive electrode portion, the negative electrode portion, the perforated separator, and the auxiliary separator therein. In the positive electrode portion, an active material removal region where the positive electrode active material is removed is formed in a region facing the perforated holes of the perforated separator.

[0016] In the battery for short-circuit inspection of the present invention, the area of the active material removal region is larger than the area of the perforated holes.

[0017] In the battery for short-circuit inspection of the present invention, the materials of the perforated separator and the auxiliary separator include at least one or more of an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, and an ethylene / methacrylate copolymer.

[0018] In the battery for short - circuit inspection of the present invention, one end of the auxiliary separator protrudes outside the battery case.

[0019] The manufacturing method of the battery for short - circuit inspection of the present invention includes: an electrode preparation step of preparing the positive electrode part in which the positive electrode active material is coated on the positive electrode current collector and the negative electrode part in which the negative electrode active material is coated on the negative electrode current collector; a positive electrode active material removal step of removing the positive electrode active material from a partial region of the positive electrode to form the active material removal region; a perforated separator lamination step of laminating a perforated separator having a perforated hole formed at a position facing the active material removal region on the positive electrode part; an auxiliary separator lamination step of laminating the auxiliary separator on the perforated separator so as to hide the perforated hole; a negative electrode lamination step of laminating the negative electrode part on the positive electrode part with the perforated separator and the auxiliary separator interposed therebetween; and a battery completion step of accommodating the positive electrode part, the negative electrode part, the perforated separator, and the auxiliary separator in a battery case and then sealing to complete the battery for short - circuit inspection.

[0020] In the positive electrode active material removal step of the manufacturing method of the battery for short - circuit inspection of the present invention, the positive electrode active material is removed by being washed with NMP (N - Methyl - 2 - pyrrolidone).

[0021] The method for analyzing the safety of the battery of the present invention includes: a battery charging step of charging the battery for short - circuit inspection; a short - circuit step of removing the auxiliary separator and bringing the positive electrode part into contact with the negative electrode part through the perforated hole; and a safety analysis step of measuring the SOC or temperature of the battery for short - circuit inspection to analyze the safety.

[0022] In the safety analysis step of the method for analyzing the safety of the battery of the present invention, the SOC or temperature of the battery for short - circuit inspection is measured in time series.

[0023] Hereinafter, with reference to the accompanying drawings, embodiments according to the present invention will be described in detail. In this process, the sizes, shapes, etc. of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. Also, terms specifically defined in consideration of the configuration and operation of the present invention may vary depending on the intention or convention of the user or operator. Definitions for such terms must be made based on the content throughout this specification.

[0024] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "one surface", "the other surface", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship usually assumed when the product of the present invention is in use. It is merely for the purpose of explaining the present invention and for a brief description, and does not imply that the indicated device or element must be configured or operated in a specific orientation in a specific direction. Therefore, it should not be understood as limiting the present invention.

[0025] FIG. 1 is a cross-sectional view showing the inside of the battery for short-circuit inspection of the present invention. FIG. 2 is a plan view showing a state in which the positive electrode portion 100 and the perforated separator 310 are laminated. FIG. 3 is a block diagram showing a manufacturing method of the battery for short-circuit inspection of the present invention. FIG. 4 is a block diagram showing a method for analyzing the safety of the battery of the present invention. FIG. 5 is a graph showing the SOC and temperature measurement results according to an embodiment.

[0026] Hereinafter, with reference to FIGS. 1 to 5, the battery for short-circuit inspection of the present invention, its manufacturing method, and a method for analyzing the safety of the battery will be described in detail.

[0027] The battery for short - circuit inspection of the present invention is provided in a state where normal charging and discharging are possible. After charging to a SOC (state of charge) value of a numerical value desired by the user, an internal short - circuit state in which the negative electrode and the positive electrode are in direct contact with each other can be easily imparted inside the battery. Therefore, by using the battery for short - circuit inspection of the present invention, it is possible to analyze the safety of the battery while driving the battery in various environments and immediately converting it to a short - circuit state at a desired time point.

[0028] As shown in FIG. 1, the battery for short - circuit inspection of the present invention includes a positive electrode part 100 formed by applying a positive electrode active material 120 to a positive electrode current collector 110; a negative electrode part 200 formed by applying a negative electrode active material 220 to a negative electrode current collector 210; a perforated separator 310 laminated between the positive electrode part 100 and the negative electrode part 200 and having perforated holes 311 formed therein; an auxiliary separator 320 covering the perforated holes 311 of the perforated separator 310 laminated between the positive electrode part 100 and the negative electrode part 200; and a battery case that houses the positive electrode part 100, the negative electrode part 200, the perforated separator 310, and the auxiliary separator 320 therein. In the positive electrode part 100, an active - material removal region 121 where the positive electrode active material 120 is removed is formed in a region facing the perforated holes 311 of the perforated separator 310.

[0029] The positive electrode current collector 110 or the negative electrode current collector 210 is made of a thin sheet in the form of a foil. Each of the positive electrode active material 120 and the negative electrode active material 220 can be formed into a layer of appropriate thickness on one or both sides of the positive electrode current collector 110 and the negative electrode current collector 210 after being applied to the positive electrode current collector 110 and the negative electrode current collector 210 in a slurry state and then dried.

[0030] The materials of the perforated separator 310 and the auxiliary separator 320 include at least one or more of an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, and an ethylene / methacrylate copolymer.

[0031] A plurality of positive electrode parts 100 and a plurality of negative electrode parts 200 are provided respectively. When a plurality of positive electrode parts 100 and a plurality of negative electrode parts 200 are provided, the positive electrode parts 100 and the negative electrode parts 200 are laminated one by one crossing each other. A separation membrane can be individually provided between each positive electrode part 100 and negative electrode part 200. That is, if a plurality of positive electrode parts 100 and a plurality of negative electrode parts 200 are provided, a plurality of separation membranes are also provided. At that time, only one or a part of the plurality of separation membranes can be provided as the perforated separation membrane 310. For example, in a state where a plurality of positive electrode parts 100, negative electrode parts 200 and separation membranes are provided respectively and laminated so as to cross each other, among the plurality of positive electrode parts 100, an active material removal region 121 is formed in the outermost positive electrode part 100, and the separation membrane facing the active material removal region 121 can be formed as the perforated separation membrane 310. As a more specific example, five positive electrode parts 100 are laminated respectively with a separation membrane sandwiched between six negative electrode parts 200. Among the five positive electrode parts 100, an active material removal region 121 is formed in one of the two positive electrode parts 100 adjacent to the outermost part, and the perforated separation membrane 310 and the auxiliary separation membrane 320 can be positioned between the positive electrode part in which the active material removal region 121 is formed and the outermost negative electrode part 200 adjacent thereto. That is, in the battery for short circuit inspection of the present invention, when a plurality of positive electrode parts 100 and a plurality of negative electrode parts 200 are provided, an active material removal region 121 is formed only in one positive electrode part 100 adjacent to the outermost part, and from the outermost part, they are laminated in the order of [negative electrode part 200]-[perforated separation membrane 310]-[auxiliary separation membrane 320]-[positive electrode part 100], or laminated in the order of [negative electrode part 200]-[auxiliary separation membrane 320]-[perforated separation membrane 310]-[positive electrode part 100]. Therefore, the positive electrode part 100 and the negative electrode part 200 can be easily brought into contact with a relatively small force by an external pressing device.

[0032] As shown in FIG. 2, the area of the active material removal region 121 can be formed larger than the area of the perforation hole 311. By forming the active material removal region 121 even larger than the perforation hole 311, it is possible to stably provide a short circuit state in which the negative electrode active material and the positive electrode current collector are in contact, rather than a short circuit in which the negative electrode active material and the positive electrode active material are in direct contact with each other.

[0033] One end of the auxiliary separation membrane 320 protrudes outside the battery case. That is, one end of the auxiliary separation membrane 320 is located outside the battery case, and the other end covers the punching hole 311 inside the battery case. When a short - circuit state is applied to the short - circuit inspection battery, the auxiliary separation membrane 320 is removed by pulling one end thereof.

[0034] As shown in FIG. 3, the method for manufacturing a short - circuit inspection battery of the present invention includes an electrode preparation step (step S1) of preparing the positive electrode part 100 in which the positive electrode active material 120 is applied to the positive electrode current collector 110 and the negative electrode part 200 in which the negative electrode active material 220 is applied to the negative electrode current collector 210; a positive electrode active material removal step (step S2) of removing the positive electrode active material 120 in a partial region of the positive electrode part 100 to form the active material removal region 121; a punching separation membrane lamination step (step S3) of laminating the punching separation membrane 310 having the punching hole 311 formed at a position facing the active material removal region 121 on the positive electrode part 100; an auxiliary separation membrane lamination step (step S4) of laminating the auxiliary separation membrane 320 on the punching separation membrane 310 so as to hide the punching hole 311; a negative electrode lamination step (step S5) of laminating the negative electrode part 200 on the positive electrode part 100 with the punching separation membrane 310 and the auxiliary separation membrane 320 interposed therebetween; and a battery completion step (step S6) of accommodating the positive electrode part 100, the negative electrode part 200, the punching separation membrane 310, and the auxiliary separation membrane 320 in a battery case and then sealing to complete the short - circuit inspection battery.

[0035] In the electrode preparation step (step S1), the positive electrode part 100 and the negative electrode part 200 can be prepared through a mixing process in which the positive electrode active material 120 and the negative electrode active material 220 are kneaded into a slurry state, a coating process in which the slurry of the positive electrode active material 120 and the slurry of the negative electrode active material 220 are respectively applied to the positive electrode current collector 110 and the negative electrode current collector 210, a pressing process in which heat is applied to and pressure is applied to the coated electrodes, a slitting process in which the electrodes are cut to meet the specifications, and a drying process in which the electrodes are dried through hot air.

[0036] In the positive electrode active material removal step (step S2), the positive electrode active material 120 is removed by being washed with NMP. The size and shape of the active material removal region 121 are determined according to the conditions required in the analysis of the battery safety. Therefore, the washing degree of the positive electrode active material 120 is also determined in consideration thereof.

[0037] In the perforated separator lamination step (step S3), as shown in FIG. 2, the size of the perforation holes 311 can be formed so as to be located within the active material removal region 121.

[0038] In the auxiliary separator lamination step (step S4), the auxiliary separator 320 is manufactured to have a sufficient size so as to completely hide the perforation holes 311. Further, since tension is generated while the other end is pulled during removal, it can be provided with a specification that does not break during removal in consideration of the tensile strength.

[0039] In the electrode preparation step (step S1) or the negative electrode lamination step (step S5), a positive electrode tab and a negative electrode tab are respectively fused to the plain portions where no active material is applied on each of the positive electrode part 100 and the negative electrode part 200, and each of the positive electrode tab and the negative electrode tab is fused to each of the positive electrode lead and the negative electrode lead for electrical connection with an external device.

[0040] In the battery completion step (step S6), the positive electrode part 100 and the negative electrode part 200 are accommodated inside the battery case so that the positive electrode lead and the negative electrode lead protrude outside the battery case, and an electrolytic solution is injected into the battery case so that the separator is sufficiently impregnated. Thereafter, the battery case is sealed after the internal gas is removed.

[0041] As shown in FIG. 4, the method for analyzing the safety of the battery of the present invention includes a battery charging stage (step S10) for charging the short-circuit test battery; a short-circuit stage (step S20) for removing the auxiliary separator 320 and bringing the positive electrode part 100 into contact with the negative electrode part 200 through the punching hole 311; and a safety analysis stage (step S30) for measuring the SOC or temperature of the short-circuit test battery to analyze the safety.

[0042] In the short-circuit stage (step S20), the short-circuit test battery is pressurized by a pressurizing device, and the positive electrode part 100 and the negative electrode part 200 are directly contacted through the punching hole 311 by the pressure applied by the pressurizing device.

[0043] In the safety analysis stage (step S30), the SOC or temperature of the short-circuit test battery is measured in time series. Characteristic information about the safety of the battery can be derived based not only on the SOC value and the temperature value, but also on the amount of change in SOC over time and the amount of change in temperature over time.

[0044] In the safety analysis stage (step S30), the temperature measurement may be performed by directly contacting a temperature sensor with the short-circuit test battery, or after the short-circuit test battery is housed in a chamber in which a sealed space is formed inside, the internal temperature of the chamber may be measured.

[0045] Example Two short-circuit test batteries were manufactured by laminating the positive electrode part 100 and the negative electrode part 200 in five layers and forming an active material removal region 121 at the center of the uppermost positive electrode part 100.

[0046] After charging the two short-circuit test batteries at 0.33C and 4.2V, the short-circuit test batteries were pressurized by a pressurizing device in a state where the auxiliary separator 320 was removed to impart a short-circuit state.

[0047] Figure 5 is a graph showing the SOC values and temperature values of two short - circuit test batteries over time after applying the short - circuit state. Both of the two short - circuit test batteries ignited between 0.5 and 1.5 seconds. In Figure 5, the solid - line graph indicates the SOC, and the dotted - line graph indicates the temperature.

[0048] As described above, the embodiments according to the present invention have been explained, but these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent - scope embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention must be determined by the scope of the claims.

Industrial Applicability

[0049] The short - circuit test battery of the present invention can arbitrarily apply a short - circuit state to a secondary battery in a desired situation, and can analyze the safety of the secondary battery by applying a short - circuit state to the secondary battery under various conditions such as different SOCs, temperatures, and impacts.

[0050] The method for analyzing the safety of the battery of the present invention can simulate the driving situation of a product to which a secondary battery is applied, apply a short - circuit state, and analyze the safety of the secondary battery.

[0051] The method for analyzing the safety of the battery of the present invention can easily confirm the presence or absence of battery safety.

Explanation of Reference Numerals

[0052] 100: Positive electrode part 110: Positive electrode current collector 120: Positive electrode active material 121: Active material removal region 200: Negative electrode part 210: Negative electrode current collector 220: Negative electrode active material 310: Perforated separator 311: Perforation hole 320: Auxiliary separator

Claims

1. A positive electrode part formed by applying a positive electrode active material to a positive electrode current collector, A negative electrode part formed by applying a negative electrode active material to a negative electrode current collector, A perforated separator laminated between the positive electrode part and the negative electrode part, with perforated holes formed therein, An auxiliary separator covering the perforated holes laminated between the positive electrode part and the negative electrode part, A battery case for housing the positive electrode part, the negative electrode part, the perforated separator, and the auxiliary separator therein, and In the positive electrode part, an active material removal region where the positive electrode active material is removed is formed in a region facing the perforated holes of the perforated separator, One end of the auxiliary separator protrudes outside the battery case, a battery for short - circuit inspection.

2. The battery for short - circuit inspection according to Claim 1, wherein the area of the active material removal region is larger than the area of the perforated holes.

3. The battery for short - circuit inspection according to Claim 1, wherein the materials of the perforated separator and the auxiliary separator include at least one or more of ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, and ethylene / methacrylate copolymer.

4. In a method for manufacturing a battery for short - circuit inspection for manufacturing the battery for short - circuit inspection according to any one of Claims 1 to 3, An electrode preparation step of preparing the positive electrode part with the positive electrode active material applied to the positive electrode current collector and the negative electrode part with the negative electrode active material applied to the negative electrode current collector, A positive electrode active material removal step of removing the positive electrode active material from a partial region of the positive electrode part to form the active material removal region, A perforated separator lamination step of laminating the perforated separator with the perforated holes formed at a position facing the active material removal region to the positive electrode part, An auxiliary separator lamination step of laminating the auxiliary separator on the perforated separator so as to hide the perforated holes, A negative electrode lamination step of laminating the negative electrode part on the positive electrode part with the perforated separator and the auxiliary separator sandwiched therebetween, A battery completion step of housing the positive electrode part, the negative electrode part, the perforated separator, and the auxiliary separator in the battery case and then sealing to complete the battery for short - circuit inspection, A method for manufacturing a battery for short - circuit inspection, including.

5. In the positive electrode active material removal step, The positive electrode active material is removed by being washed with NMP. The method for manufacturing a battery for short - circuit inspection according to Claim 4.

6. In a method for analyzing the safety of a battery using the battery for short - circuit inspection according to Claim 1, A battery charging step of charging the battery for short - circuit inspection, A short-circuit step of removing the auxiliary separation membrane and bringing the positive electrode portion into contact with the negative electrode portion through the punched holes; A safety analysis step of measuring the SOC or temperature of the short-circuit test battery to analyze safety; A method for analyzing the safety of a battery, comprising:

7. In the safety analysis step, The method for analyzing the safety of a battery according to claim 6, wherein the SOC or temperature of the short-circuit test battery is measured in time series.

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