Improved safety of prismatic secondary batteries

Abstract

The disclosed invention relates to a prismatic secondary battery including an electrode assembly having a stack structure in which unit cells are stacked, and in one example, the electrode assembly includes positive and negative electrode tabs electrically connected to positive and negative electrode terminals, respectively, provided on a case of the prismatic secondary battery, and positive and negative electrode dummy tabs electrically isolated from the positive and negative electrode terminals.

Description

[Technical Field]

[0001] The present invention relates to a prismatic secondary battery having improved safety by preventing internal slippage of an electrode assembly.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0044302, filed April 11, 2022, and Korean Patent Application No. 10-2023-0043523, filed April 3, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference. [Background technology]

[0003] Unlike primary batteries, secondary batteries are rechargeable and have the potential to be small and have large capacities, which has led to extensive research and development in recent years. Demand for secondary batteries as an energy source is rapidly increasing due to the increasing technological development and demand for mobile devices, as well as the emergence of electric vehicles and energy storage systems in response to modern demands for environmental protection.

[0004] Secondary batteries are classified into coin-type batteries, cylindrical batteries, prismatic batteries, and pouch-type batteries depending on the shape of the battery case. The electrode assembly installed inside the battery case of a secondary battery is a power generating element that can be charged and discharged and is made up of a laminated structure of electrodes and a separator.

[0005] Electrode assemblies can be broadly classified into a jellyroll type in which a sheet-like positive electrode and negative electrode coated with an active material are wound up with a separator interposed between them; a stack type in which multiple positive electrodes and negative electrodes are stacked in sequence with a separator interposed between them; and a stack and folding type in which stack-type unit cells are wound up with a long separator film.

[0006] The positive and negative electrode tabs of the electrode assembly housed in a prismatic secondary battery are joined to electrode leads, respectively, and then connected to the positive and negative terminals on the case. The case housing the electrode assembly has some extra space for electrical connections of the electrode assembly and for the required amount of electrolyte. Therefore, the electrode assembly inside the case may shake or slip due to external impact. In particular, prismatic secondary batteries used in hybrid and electric vehicles frequently experience slippage due to impacts while driving.

[0007] The structural support of the electrode assembly is mainly provided by the positive and negative electrode tabs (electrode tabs) connected to the positive and negative terminals. Therefore, if slippage occurs in the electrode assembly, various problems can occur, such as a short circuit due to electrical contact or stress concentration on the electrode tabs, causing them to break. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Korean Patent No. 10-0929034 (published November 20, 2009) Summary of the Invention [Problem to be solved by the invention]

[0009] SUMMARY OF THE INVENTION An object of the present invention is to prevent an electrode assembly housed inside a prismatic secondary battery from slipping during use.

[0010] However, the technical problems that the present invention aims to solve are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below. [Means for solving the problem]

[0011] The present invention relates to a prismatic secondary battery including an electrode assembly having a stack structure in which unit cells are stacked. In one example, the electrode assembly includes a positive electrode tab and a negative electrode tab electrically connected to a positive electrode terminal and a negative electrode terminal, respectively, provided on a case of the prismatic secondary battery, and a positive electrode dummy tab and a negative electrode dummy tab electrically isolated from the positive electrode terminal and the negative electrode terminal.

[0012] The positive electrode dummy tab and the negative electrode dummy tab are fixed to the case to support the electrode assembly.

[0013] In one embodiment of the present invention, the positive electrode terminal and the negative electrode terminal are both arranged on one surface of the case, and the positive electrode dummy tab and the negative electrode dummy tab are fixed to an opposing surface opposite to the surface on which the positive electrode terminal and the negative electrode terminal are both arranged.

[0014] Here, each pair of the positive electrode tab and the positive electrode dummy tab, and each pair of the negative electrode tab and the negative electrode dummy tab may be aligned to be positioned on a straight line that crosses the one surface and the opposite surface.

[0015] Alternatively, each pair of the positive electrode tab and the positive electrode dummy tab, and each pair of the negative electrode tab and the negative electrode dummy tab may be arranged offset from each other along a direction crossing the one surface and the opposing surface.

[0016] Alternatively, each pair of the positive electrode tab and the negative electrode dummy tab, and each pair of the negative electrode tab and the positive electrode dummy tab may be aligned so as to be positioned on a straight line that crosses the one surface and the opposing surface.

[0017] In another embodiment of the present invention, the positive electrode terminal and the negative electrode terminal are arranged separately on two opposing surfaces of the case, and the positive electrode dummy tab is fixed to the surface on which the positive electrode terminal is arranged, while the negative electrode dummy tab is fixed to the surface on which the negative electrode terminal is arranged.

[0018] Alternatively, the positive electrode terminal and the negative electrode terminal may be separately arranged on two opposing surfaces of the case, and the positive electrode dummy tab may be fixed to the surface on which the negative electrode terminal is arranged, while the negative electrode dummy tab may be fixed to the surface on which the positive electrode terminal is arranged.

[0019] Here, the positive electrode dummy tab and the negative electrode dummy tab may be aligned to be positioned on a straight line that crosses the two opposing surfaces.

[0020] Either the positive electrode dummy tab or the negative electrode dummy tab may be electrically insulated from the case.

[0021] For example, a dummy tab that is electrically insulated from the case may be fixed to an insulator mounted on the inner surface of the case.

[0022] The insulator may have a tab insertion groove, and the dummy tab may be inserted into the tab insertion groove and fixed.

[0023] A dummy tab that is not electrically insulated from the case can then be welded to the inside surface of the case.

[0024] Meanwhile, according to an embodiment of the present invention, at least one of the positive electrode dummy tab and the negative electrode dummy tab may be provided in plural numbers. [Effects of the Invention]

[0025] The electrode assembly of the prismatic secondary battery of the present invention having the above-described configuration includes a positive electrode dummy tab and a negative electrode dummy tab on the opposite side of the positive electrode tab and the negative electrode tab, and the positive electrode dummy tab and the negative electrode dummy tab are fixed to the case.

[0026] As a result, the electrode assembly is fixed in both directions within the case, improving the support structure. As a result, the electrode assembly housed inside the prismatic secondary battery is prevented from slipping during use, preventing various problems such as short circuits due to electrical contact and broken tabs, thereby significantly improving the safety of the secondary battery.

[0027] However, the technical effects that can be obtained by the present invention are not limited to the effects described above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

[0028] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical concept of the present invention, and therefore the present invention should not be interpreted as being limited solely to the matters depicted in such drawings. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a view illustrating the outer shape of a prismatic secondary battery according to an embodiment of the present invention; [Figure 2] 2 is a view illustrating an electrode assembly housed in the prismatic secondary battery of FIG. 1; [Figure 3] 2 is a view illustrating a support structure of an electrode assembly in the prismatic secondary battery of FIG. 1; [Figure 4] 10 is a view illustrating another electrode assembly according to an embodiment of the present invention; [Figure 5] 1 is a view illustrating another electrode assembly according to an embodiment of the present invention; [Figure 6] 10 is a view illustrating the outer shape of a prismatic secondary battery according to another embodiment of the present invention. [Figure 7] 7 is a view illustrating an electrode assembly housed in the prismatic secondary battery of FIG. 6; [Figure 8] 7 is a view illustrating a support structure of an electrode assembly in the prismatic secondary battery of FIG. 6. [Figure 9]10 is a view illustrating another electrode assembly according to another embodiment of the present invention; [Figure 10] 10 is a view illustrating another embodiment of a unidirectional electrode assembly. [Figure 11] 10 is a view illustrating another embodiment of a bidirectional electrode assembly. DETAILED DESCRIPTION OF THE INVENTION

[0030] Because the present invention can be modified in various ways and can have various embodiments, specific embodiments will be described in detail below.

[0031] However, this is not intended to limit the invention to any particular embodiment, but should be understood to include all modifications, equivalents, or alternatives falling within the spirit and scope of the invention.

[0032] In the present invention, the terms "comprise" and "have" are intended to specify the presence of features, numbers, steps, operations, components, parts or combinations thereof described in the specification, and should be understood as not precluding the presence or possibility of addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0033] Furthermore, in the present invention, when a layer, film, region, plate, or other portion is described as being "on" another portion, this includes not only the case where it is "directly on" the other portion, but also the case where there is another portion therebetween. Conversely, when a layer, film, region, plate, or other portion is described as being "under" the other portion, this includes not only the case where it is "directly under" the other portion, but also the case where there is another portion therebetween. Furthermore, in this application, being "located on" can include not only the case where it is located at the top, but also the case where it is located at the bottom.

[0034] The present invention relates to a prismatic secondary battery including an electrode assembly having a stack structure in which unit cells are stacked. In one example, the electrode assembly includes a positive electrode tab and a negative electrode tab electrically connected to a positive electrode terminal and a negative electrode terminal, respectively, provided on a case of the prismatic secondary battery, and a positive electrode dummy tab and a negative electrode dummy tab electrically isolated from the positive electrode terminal and the negative electrode terminal.

[0035] Here, the positive electrode dummy tab and the negative electrode dummy tab are fixed to the case to support the electrode assembly.

[0036] As described above, the electrode assembly of the prismatic secondary battery according to the present invention includes a positive electrode dummy tab and a negative electrode dummy tab on the opposite side of the positive electrode tab and the negative electrode dummy tab are fixed to the case. Therefore, the electrode assembly is fixed in both directions within the case, improving the support structure. As a result, the electrode assembly housed inside the prismatic secondary battery is prevented from slipping during use, and various problems such as short circuits due to electrical contact and tab breakage are prevented, thereby significantly improving the safety of the secondary battery.

[0037] Hereinafter, specific embodiments of the prismatic secondary battery of the present invention will be described in detail with reference to the accompanying drawings. For reference, the directions of front, back, up, down, left, and right used in the following description to designate relative positions are intended to facilitate understanding of the invention, and unless otherwise specified, are based on the directions shown in the drawings.

[0038] (First embodiment) FIG. 1 is a view illustrating the outer shape of a prismatic secondary battery 100 according to a first embodiment of the present invention, and FIG. 2 is a view illustrating an electrode assembly 200 housed in the prismatic secondary battery 100 of FIG. 1.

[0039] The prismatic secondary battery 100 in the first embodiment relates to a one-way secondary battery in which a positive electrode terminal 120 and a negative electrode terminal 130 are both arranged on one surface of a case 110, in the illustrated example, the top surface. An electrode assembly 200 having a stack structure in which unit cells are stacked is sealed and housed in the case 110. A unit cell refers to a cell having a unit structure of a positive electrode / separator / negative electrode, and one electrode assembly 200 is constructed by stacking a plurality of unit cells. The general structure of a unit cell is as follows.

[0040] The positive electrode includes a positive electrode current collector and a positive electrode active material coated on one or both sides of the positive electrode current collector. One widthwise end of the positive electrode current collector has a blank area where the positive electrode active material is not coated. The blank area is notched (punched) to form a positive electrode tab 210.

[0041] The negative electrode includes a negative electrode current collector and a negative electrode active material coated on one or both sides of the negative electrode current collector. One widthwise end of the negative electrode current collector has a non-coated portion where the negative electrode active material is not coated. Similarly, the non-coated portion of the negative electrode functions as a negative electrode tab 220.

[0042] As a result, the positive electrode tab 210 and the negative electrode tab 220 in the first embodiment are located at the same end in the width direction of the electrode assembly 200, i.e., in the height direction of the prismatic secondary battery 100. In the illustrated example, the positive electrode tab 210 and the negative electrode tab 220 extend toward the top surface of the prismatic secondary battery 100, and the positive electrode tab 210 and the negative electrode tab 220 are electrically connected to the positive electrode terminal 120 and the negative electrode terminal 130, respectively, provided on the case 110 of the prismatic secondary battery 100.

[0043] In the present invention, the positive electrode active material coated on the positive electrode current collector and the negative electrode active material coated on the negative electrode current collector may be any active material known in the art without limitation.

[0044] In one example, the positive electrode active material has the general chemical formula A[A x M y ]O 2+z(A includes at least one element selected from Li, Na, and K; M includes at least one element selected from Ni, Co, Mn, Ca, Mg, Al, Ti, Si, Fe, Mo, V, Zr, Zn, Cu, Sc, Ru, and Cr; x≧0, 1≦x+y≦2, 0.1≦z≦2; and the stoichiometric coefficients of x, y, z, and the components in M ​​are selected so that the compound maintains electroneutrality).

[0045] In another example, the positive electrode active material is an alkali metal compound xLiM disclosed in US Pat. No. 6,677,082, US Pat. No. 6,680,143, etc. 1 O2(1x)Li2M 2 O3(M 1 contains at least one element having an average oxidation state of 3; M 2 may contain at least one element having an average oxidation state of 4; 0≦x≦1).

[0046] In another example, the positive electrode active material has the general chemical formula Li a M 1 x Fe 1x M 2 y P 1y M 3 z O 4z (M 1 contains at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Mg and Al; M 2 contains at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, As, Sb, Si, Ge, V and S; M 3 contains halogen elements, optionally including F; <a≦2、0≦x≦1、0≦y<1、0≦z<1;a、x、y、z、M 1 , M 2 , and M 3wherein the stoichiometric coefficients of the components in are selected to maintain electroneutrality of the compound), or lithium metal phosphate, represented by Li3M2(PO4)3, where M comprises at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Mg, and Al.

[0047] Preferably, the positive electrode active material may contain primary particles and / or secondary particles formed by aggregation of primary particles.

[0048] For example, the negative electrode active material may be a carbon material, lithium metal or a lithium metal compound, silicon or a silicon compound, or tin or a tin compound. Metal oxides with a potential of less than 2 V, such as TiO2 and SnO2, may also be used as the negative electrode active material. The carbon material may be either low-crystalline carbon or high-crystalline carbon.

[0049] The separator interposed between the positive electrode and the negative electrode may be a porous polymer film, for example, a porous polymer film made of a polyolefin polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, an ethylene / methacrylate copolymer, etc., either alone or in a laminated state. As another example, the separator may be made of a conventional porous nonwoven fabric, for example, a nonwoven fabric made of a high-melting point glass fiber, a polyethylene terephthalate fiber, etc.

[0050] At least one surface of the separator may include a coating layer of inorganic particles. Alternatively, the separator itself may be made of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure in which they are bound with a binder so that there is interstitial volume between adjacent particles.

[0051] The inorganic particles may be made of an inorganic material having a dielectric constant of 5 or more. Non-limiting examples of the inorganic particles include Pb(Zr,Ti)O3 (PZT), Pb 1x La x Zr1y Ti y O3(PLZT), PB(Mg3Nb 2 / 3 )O3PbTiO3 (PMNPT), BaTiO3, hafnia (HfO2), SrTiO3, TiO2, Al2O3, ZrO2, SnO2, CeO2, MgO, CaO, ZnO, and Y2O3.

[0052] The electrolyte that constitutes the electrolyte solution in which the electrode assembly 200 is impregnated is A + B - The salt may have the structure: + Li + , Na + , K. + and alkali metal cations such as B - is F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , AlO4 - , AlCl4 - , PF6 - , SbF6 - , AsF6 - , BF2C2O4 - , BC4O8 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , C4F9SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C -, CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - and (CF3CF2SO2)2N - The compound contains one or more anions selected from the group consisting of:

[0053] The electrolyte may also be dissolved in an organic solvent, such as propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (EMC), gamma-butyrolactone, or a mixture thereof.

[0054] 2 , the electrode assembly 200 in the first embodiment includes a positive electrode tab 210 and a negative electrode tab 220 electrically connected to the positive electrode terminal 120 and the negative electrode terminal 130, respectively, provided on the case 110 of the prismatic secondary battery 100, and also includes a positive electrode dummy tab 230 and a negative electrode dummy tab 240 electrically isolated from the positive electrode terminal 120 and the negative electrode terminal 130. The positive electrode dummy tab 230 and the negative electrode dummy tab 240 are formed in uncoated areas opposite the uncoated areas on which the positive electrode tab 210 and the negative electrode tab 220 are formed. Therefore, in the first embodiment, the positive electrode tab 210 and the negative electrode tab 220 are disposed at opposite ends of the electrode assembly 200, i.e., at the upper end of the electrode assembly 200 in the drawing, while the positive electrode dummy tab 230 and the negative electrode dummy tab 240 are disposed at the lower end of the electrode assembly 200.

[0055] 3 is a diagram illustrating a support structure for the electrode assembly 200 in the prismatic secondary battery 100 of FIG 1. As shown in the diagram, the positive electrode tab 210 and the negative electrode tab 220 are fixed to the positive electrode terminal 120 and the negative electrode terminal 130 on the top surface of the case 110 by welding, and the positive electrode dummy tab 230 and the negative electrode dummy tab 240 are fixed to the bottom surface of the case 110.

[0056] As described above, in the prismatic secondary battery 100 according to the first embodiment of the present invention, the electrode assembly 200 is fixed to the case 110 at both the upper and lower ends. More specifically, the positive electrode tab 210, the negative electrode tab 220, the positive electrode dummy tab 230, and the negative electrode dummy tab 240 form a four-point support structure to fix the electrode assembly 200 to the case 110. The four-point support structure provides strong support against external disturbances, and the electrode assembly 200 supported at four points is less likely to slip during use, preventing various problems such as short circuits due to electrical contact and breakage of the electrode tabs 210 and 220. As a result, the safety of the prismatic secondary battery 100 is significantly improved.

[0057] Since the positive electrode dummy tab 230 and the negative electrode dummy tab 240 are integrally formed with the positive and negative electrodes of the electrode assembly 200, if the case 110 has polarity, at least one of the dummy tabs 230 or 240 must be electrically insulated from the case 110 to prevent an internal short circuit. That is, if the case 110 is electrically positive, the negative electrode dummy tab 240 must be electrically insulated from the case 110, and conversely, if the case 110 is electrically negative, the positive electrode dummy tab 230 must be insulated. If the case 110 is electrically neutral, the dummy tabs 230 and 240 do not necessarily need to be insulated from the case 110.

[0058] 3 illustrates an example in which the case 110 is electrically negative, e.g., grounded, and the positive electrode dummy tab 230 is fixed to an insulator 300 installed on the inner surface of the case 110. The positive electrode dummy tab 230 fixed to the case 110 via the insulator 300 is electrically isolated from the case 110. For example, the insulator 300 has a tab insertion groove 310, and the positive electrode dummy tab 230 can be fixed by being inserted into the tab insertion groove 310 of the insulator 300 and compressed.

[0059] The negative electrode dummy tab 240 can also be fixed to the case 110 using the insulator 300, and since it does not necessarily need to be insulated from the electrically negative case 110, it is of course possible for the negative electrode dummy tab 240 to be directly welded and fixed to the inner surface of the case 110.

[0060] Figure 4 is a view illustrating another electrode assembly 200 according to an embodiment of the present invention, and Figure 5 is a view illustrating another electrode assembly 200 according to an embodiment of the present invention. Figures 4 and 5 show that the arrangement relationship of the positive electrode dummy tab 230 and the negative electrode dummy tab 240 with respect to the positive electrode tab 210 and the negative electrode tab 220 can be configured in various ways, while the four-point support structure of the electrode assembly 200 remains the same.

[0061] 2, each pair of positive electrode tab 210 and positive electrode dummy tab 230, and each pair of negative electrode tab 220 and negative electrode dummy tab 240 are aligned so as to be located on a straight line that intersects one surface and the opposing surface of electrode assembly 200, i.e., a straight line that intersects the height direction (width direction of the electrode assembly) of case 110. In other words, positive electrode dummy tab 230 faces positive electrode tab 210, and negative electrode dummy tab 240 faces negative electrode tab 220.

[0062] In comparison, in the electrode assembly 200 of Fig. 4, each pair of positive electrode tabs 210 and positive electrode dummy tabs 230, and each pair of negative electrode tabs 220 and negative electrode dummy tabs 240 are offset from one another in a direction transverse to one surface and the opposing surface. In other words, the electrode assembly 200 of Fig. 4 has a structure in which the positive electrode dummy tabs 230 and negative electrode dummy tabs 240 are offset from the opposing structures of the positive electrode tabs 210 and negative electrode tabs 220. Breaking the four-point support vertical symmetry structure changes the natural frequency, making it possible to respond to various types of vibration.

[0063] 5 is a modification of FIG. 2, in which each pair of positive electrode tab 210 and negative electrode dummy tab 240, and each pair of negative electrode tab 220 and positive electrode dummy tab 230, are aligned to be located on a straight line that intersects one surface and the opposite surface of the electrode assembly 200. In other words, the negative electrode dummy tab 240 faces the positive electrode tab 210, and the positive electrode dummy tab 230 faces the negative electrode tab 220. The type (polarity) of the dummy tabs 230, 240 facing each electrode tab 210, 220 is not limited to the embodiment of FIG. 2.

[0064] (Second embodiment) FIG. 6 is a view illustrating the outer shape of a prismatic secondary battery 100 according to a second embodiment of the present invention, and FIG. 7 is a view illustrating an electrode assembly 200 housed in the prismatic secondary battery 100 of FIG. 6.

[0065] The prismatic secondary battery 100 according to the second embodiment of the present invention relates to a bidirectional secondary battery in which the positive terminal 120 and the negative terminal 130 are separately disposed on two opposing surfaces of the case 110. Accordingly, the electrode assembly 200 in which the unit cells are stacked also differs from the first embodiment in the arrangement of the dummy tabs 230 and 240. The second embodiment of the present invention will be described focusing on the configuration that is distinguishable from the first embodiment.

[0066] 7, corresponding to the positive electrode terminal 120 and the negative electrode terminal 130 arranged separately on opposite surfaces, the positive electrode tab 210 and the negative electrode tab 220 are also arranged separately on the left and right ends of the electrode assembly 200. The positive electrode dummy tab 230 is fixed to the surface on which the positive electrode terminal 120 is arranged, whereas the negative electrode dummy tab 240 is fixed to the surface on which the negative electrode terminal 130 is arranged.

[0067] 7, the positive electrode tab 210 and the positive electrode dummy tab 230 are both arranged on one side of the case 110 (the left side in the drawing), and the negative electrode tab 220 and the negative electrode dummy tab 240 are both arranged on the opposite side of the case 110 (the right side in the drawing). The positions of the electrode tabs 210, 220 and the dummy tabs 230, 240 provided on the electrode assembly 200 have changed depending on the terminal arrangement of the prismatic secondary battery 100. However, as shown in FIG. 8, the four-point support structure of the electrode assembly 200 is maintained in the second embodiment, and either the positive electrode dummy tab 230 or the negative electrode dummy tab 240 can be electrically insulated from the case 110.

[0068] 9 is a view illustrating another electrode assembly 200 according to a second embodiment of the present invention. In FIG. 9, the positive electrode dummy tab 230 is fixed to the surface on which the negative electrode terminal 130 is disposed, while the negative electrode dummy tab 240 is fixed to the surface on which the positive electrode terminal 120 is disposed. That is, in the electrode assembly 200 of FIG. 9, the positive electrode tab 210 and the negative electrode dummy tab 240 are both disposed on one surface of the case 110 (the left side in the drawing), and the negative electrode tab 220 and the positive electrode dummy tab 230 are both disposed on the opposite surface of the case 110 (the right side in the drawing). In other words, as long as the four-point support structure of the electrode assembly 200 is maintained, the protruding positions of the positive electrode dummy tab 230 and the negative electrode dummy tab 240 are not particularly important.

[0069] Here, the positive electrode dummy tab 230 and the negative electrode dummy tab 240 can be aligned so as to be positioned on a straight line that intersects two opposing surfaces, i.e., two surfaces on which the positive electrode tab 210 and the negative electrode tab 220 are arranged to face each other. In other words, similar to the arrangement of the positive electrode tab 210 and the negative electrode tab 220, the positive electrode dummy tab 230 and the negative electrode dummy tab 240 can also be arranged to face each other accurately.

[0070] (Third embodiment) In the above-described first and second embodiments, electrode assemblies suitable for application to one-way secondary batteries and bidirectional secondary batteries, respectively, have been described, and in each embodiment, one positive electrode dummy tab and one negative electrode dummy tab have been provided as an example. However, in order to further strengthen the support structure of the electrode assembly in a prismatic secondary battery, multiple dummy tabs may be provided, and the third embodiment relates to this.

[0071] 10 illustrates a unidirectional electrode assembly in which the positive electrode tab 210 and the negative electrode tab 220 are both arranged on the upper end of the electrode assembly 200. As shown in FIG. 10, a plurality of positive electrode dummy tabs 230 and a plurality of negative electrode dummy tabs 240 (two of each in the illustrated example) may be provided. The support structure of the electrode assembly 200 may be further strengthened by the plurality of dummy tabs 230, 240.

[0072] FIG. 11 illustrates a third embodiment of a bidirectional electrode assembly in which positive electrode tabs 210 and negative electrode tabs 220 are separately arranged on two opposing surfaces of the electrode assembly 200, and multiple positive electrode dummy tabs 230 and multiple negative electrode dummy tabs 240 are provided on the same surface as the positive electrode tabs 210 and negative electrode tabs 220, respectively.

[0073] Of course, the configurations of the insulator 300, the tab insertion groove 310, etc. described in the first and second embodiments can be equally applied to the third embodiment, except for the fact that a plurality of dummy tabs 230, 240 are provided. 10 and 11 illustrate that a plurality of positive electrode dummy tabs 230 and a plurality of negative electrode dummy tabs 240 are provided, and that the same number of both are provided, but this is merely an example, and it is possible for a plurality of either the positive electrode dummy tabs 230 or the negative electrode dummy tabs 240, or for the numbers of the positive electrode dummy tabs 230 and the negative electrode dummy tabs 240 to be provided.

[0074] The present invention has been described in more detail above with reference to the drawings and embodiments, etc. However, the configurations described in the drawings or embodiments in this specification are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention, so it should be understood that there may be various equivalents and modifications that can replace them at the time of filing this application. [Explanation of symbols]

[0075] 100: Prismatic secondary battery 110: Case 120: Positive terminal 130: Negative terminal 200: Electrode assembly 210: Positive electrode tab 220: Negative electrode tab 230: Positive dummy tab 240: Negative dummy tab 300: Insulator 310: Tab insertion groove

Claims

1. A prismatic secondary battery having an electrode assembly with a stack structure in which unit cells are stacked, The electrode assembly is a positive electrode tab and a negative electrode tab electrically connected to a positive electrode terminal and a negative electrode terminal, respectively, provided on a case of the prismatic secondary battery; a positive electrode dummy tab and a negative electrode dummy tab electrically isolated from the positive electrode terminal and the negative electrode terminal, The positive electrode dummy tab and the negative electrode dummy tab are a support member fixed to the case to support the electrode assembly; The positive electrode tab, the negative electrode tab, the positive electrode dummy tab, and the negative electrode dummy tab support the electrode assembly from both directions.

2. A prismatic secondary battery having an electrode assembly with a stack structure in which unit cells are stacked, The electrode assembly is a positive electrode tab and a negative electrode tab electrically connected to a positive electrode terminal and a negative electrode terminal, respectively, provided on a case of the prismatic secondary battery; a positive electrode dummy tab and a negative electrode dummy tab electrically isolated from the positive electrode terminal and the negative electrode terminal, The positive electrode dummy tab and the negative electrode dummy tab are a support member fixed to the case to support the electrode assembly; the positive terminal and the negative terminal are both disposed on one surface of the case, the positive electrode dummy tab and the negative electrode dummy tab are fixed to an opposing surface opposite to one surface on which the positive electrode terminal and the negative electrode terminal are both arranged.

3. 3. The prismatic secondary battery according to claim 2, wherein each pair of the positive electrode tab and the positive electrode dummy tab, and each pair of the negative electrode tab and the negative electrode dummy tab are aligned so as to be positioned on a straight line intersecting the one surface and the opposing surface.

4. 3. The prismatic secondary battery according to claim 2, wherein each pair of the positive electrode tab and the positive electrode dummy tab, and each pair of the negative electrode tab and the negative electrode dummy tab are arranged offset from each other along a direction transverse to the one surface and the opposing surface.

5. 5. The prismatic secondary battery according to claim 4, wherein each pair of the positive electrode tab and the negative electrode dummy tab, and each pair of the negative electrode tab and the positive electrode dummy tab, are aligned so as to be positioned on a straight line intersecting the one surface and the opposing surface.

6. A prismatic secondary battery having an electrode assembly with a stack structure in which unit cells are stacked, The electrode assembly is a positive electrode tab and a negative electrode tab electrically connected to a positive electrode terminal and a negative electrode terminal, respectively, provided on a case of the prismatic secondary battery; a positive electrode dummy tab and a negative electrode dummy tab electrically isolated from the positive electrode terminal and the negative electrode terminal, The positive electrode dummy tab and the negative electrode dummy tab are a support member fixed to the case to support the electrode assembly; the positive electrode terminal and the negative electrode terminal are separately arranged on two opposing surfaces of the case, the positive electrode dummy tab is fixed to a surface on which the positive electrode terminal is disposed, whereas the negative electrode dummy tab is fixed to a surface on which the negative electrode terminal is disposed.

7. A prismatic secondary battery having an electrode assembly with a stack structure in which unit cells are stacked, The electrode assembly is a positive electrode tab and a negative electrode tab electrically connected to a positive electrode terminal and a negative electrode terminal, respectively, provided on a case of the prismatic secondary battery; a positive electrode dummy tab and a negative electrode dummy tab electrically isolated from the positive electrode terminal and the negative electrode terminal, The positive electrode dummy tab and the negative electrode dummy tab are a support member fixed to the case to support the electrode assembly; the positive electrode terminal and the negative electrode terminal are separately arranged on two opposing surfaces of the case, the positive electrode dummy tab is fixed to a surface on which the negative electrode terminal is disposed, whereas the negative electrode dummy tab is fixed to a surface on which the positive electrode terminal is disposed.

8. The prismatic secondary battery according to claim 6 or 7, wherein the positive electrode dummy tab and the negative electrode dummy tab are aligned so as to be positioned on a straight line that crosses the two opposing surfaces.

9. 8. The prismatic secondary battery according to claim 1, wherein one of the positive electrode dummy tab and the negative electrode dummy tab is electrically insulated from the case.

10. The prismatic secondary battery according to claim 9 , wherein the dummy tab, which is electrically insulated from the case, is fixed to an insulator disposed on the inner surface of the case.

11. A prismatic secondary battery having an electrode assembly with a stack structure in which unit cells are stacked, The electrode assembly is a positive electrode tab and a negative electrode tab electrically connected to a positive electrode terminal and a negative electrode terminal, respectively, provided on a case of the prismatic secondary battery; a positive electrode dummy tab and a negative electrode dummy tab electrically isolated from the positive electrode terminal and the negative electrode terminal, The positive electrode dummy tab and the negative electrode dummy tab are a support member fixed to the case to support the electrode assembly; one of the positive electrode dummy tab and the negative electrode dummy tab is electrically insulated from the case; a dummy tab electrically insulated from the case is fixed to an insulator disposed on the inner surface of the case; The insulator has a tab insertion groove, The dummy tab is inserted into the tab insertion groove and fixed in place.

12. A prismatic secondary battery having an electrode assembly with a stack structure in which unit cells are stacked, The electrode assembly is a positive electrode tab and a negative electrode tab electrically connected to a positive electrode terminal and a negative electrode terminal, respectively, provided on a case of the prismatic secondary battery; a positive electrode dummy tab and a negative electrode dummy tab electrically isolated from the positive electrode terminal and the negative electrode terminal, The positive electrode dummy tab and the negative electrode dummy tab are a support member fixed to the case to support the electrode assembly; one of the positive electrode dummy tab and the negative electrode dummy tab is electrically insulated from the case; a dummy tab electrically insulated from the case is fixed to an insulator disposed on the inner surface of the case; A prismatic secondary battery, wherein a dummy tab that is not electrically insulated from the case is welded to the inner surface of the case.

13. The prismatic secondary battery according to claim 1 , wherein at least one of the positive electrode dummy tab and the negative electrode dummy tab is provided in a plurality of pieces.

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