Prismatic secondary battery and its manufacturing method

Abstract

A rectangular secondary cell comprises an electrode body, a collector body connected to an end side of the electrode body, and an external terminal connected to the collector body, and in the collector body, a first connection part connected to the external terminal and a second connection part connected to the end side of the electrode body are constituted integrally from the same member, the first connection part passing through a through hole provided in a sealing plate and the external terminal, the tip part of the first connection part being crimped and connected to the external terminal, and the collector body and the external terminal being fixed to the sealing plate.

Description

[Technical field]

[0001] The present disclosure relates to a prismatic secondary battery and a manufacturing method thereof. [Background technology]

[0002] 2. Description of the Related Art A known current collecting structure for a secondary battery is one in which an electrode assembly including a positive electrode plate and a negative electrode plate is connected to an external terminal via a current collector.

[0003] 37, Patent Document 1 discloses a secondary battery 100 in which a current collector 120 is connected to an end of an electrode body 110, and an end 120A of the current collector 120 is connected to an external terminal 130. The cylindrical portion 130A of the external terminal 130 penetrates through holes provided in the insulating member 150, the sealing plate 140, the insulating member 160, and the connection portion 120A of the current collector 120, respectively, and protrudes to the inside of the sealing plate 140, and the tip portion of the cylindrical portion 130A is crimped. As a result, the current collector 120 is connected to the external terminal 130, and the current collector 120 and the external terminal 130 are fixed to the sealing plate 140. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Patent Publication No. 2017 / 131168 Summary of the Invention

[0005] In the secondary battery having the current collecting structure disclosed in Patent Document 1, the tip of the cylindrical portion 130A of the external terminal 130 penetrates an opening hole provided in the connection portion 120A of the current collector 120, and is crimped to protrude inside the sealing plate 140. Therefore, a certain distance required for crimping must be provided between the crimped portion and the electrode body 110. In addition, when the tip of the cylindrical portion 130A is crimped, a large load is applied to the connection portion 120A of the current collector 120. Therefore, the insulating member 160 and the connection portion 120A of the current collector 120 must each have a thickness that provides the rigidity to withstand the load during crimping. As a result, as shown in FIG. 37, the distance D between the sealing plate 140 and the electrode body 110 becomes large.

[0006] The space created between the sealing plate 140 and the electrode body 110 becomes dead space that does not contribute to the battery capacity. Therefore, if the distance D between the sealing plate 140 and the electrode body 110 is large, it will hinder the secondary battery from having a high capacity and a high energy density. In particular, secondary batteries for vehicle use are required to have a low cell height in addition to a large size, so in order to achieve a high capacity and high energy density of the secondary battery, it is necessary to reduce the distance D between the sealing plate 140 and the electrode body 110.

[0007] The prismatic secondary battery according to the present disclosure comprises an electrode body having a positive electrode plate and a negative electrode plate, a prismatic battery case having an opening and housing the electrode body, a sealing plate sealing the opening, a current collector connected to the end edge of the positive electrode plate or the negative electrode plate at a longitudinal end of the sealing plate, and an external terminal provided on the outside of the sealing plate and connected to the current collector, the current collector having a first connection portion connected to the external terminal and a second connection portion connected to the end edge of the positive electrode plate or the negative electrode plate, the first connection portion penetrating through holes provided in the sealing plate and the external terminal from the inside to the outside of the sealing plate, and the tip of the first connection portion is crimped to connect to the external terminal, and the current collector and the external terminal are fixed to the sealing plate.

[0008] According to the present disclosure, it is possible to provide a secondary battery having a current collection structure suitable for achieving high capacity and high energy density. [Brief description of the drawings]

[0009] [Figure 1A] FIG. 1A is a top view illustrating a schematic configuration of a prismatic secondary battery in one embodiment of the present disclosure. [Figure 1B] FIG. 1B is a cross-sectional view taken along line Ib-Ib in FIG. 1A. [Diagram 2] FIG. 2 is a perspective view that illustrates a schematic configuration of a current collector in this embodiment. [Diagram 3] FIG. 3 is a diagram illustrating the assembly procedure of the prismatic secondary battery in this embodiment. [Figure 4] FIG. 4 is a diagram illustrating the assembly procedure of the prismatic secondary battery in this embodiment. [Figure 5A] FIG. 5A is a diagram illustrating the assembly procedure of the prismatic secondary battery in this embodiment. [Figure 5B] FIG. 5B is a diagram illustrating the assembly procedure of the prismatic secondary battery in this embodiment. [Figure 6] FIG. 6 is a diagram illustrating the assembly procedure of the prismatic secondary battery in this embodiment. [Figure 7] FIG. 7 is a diagram illustrating the assembly procedure of the prismatic secondary battery in this embodiment. [Figure 8] FIG. 8 is a diagram illustrating the assembly procedure of the prismatic secondary battery in this embodiment. [Figure 9] FIG. 9 is a diagram illustrating the assembly procedure of the prismatic secondary battery in this embodiment. [Figure 10] FIG. 10 is a perspective view that illustrates a schematic configuration of a current collector in the first modification. [Figure 11] FIG. 11 is a partial perspective view showing a state in which a current collector is sandwiched between exposed portions of an electrode assembly in the first modification. [Figure 12A] FIG. 12A is a cross-sectional perspective view taken along line XIIa-XIIa in FIG. [Figure 12B] FIG. 12B is a cross-sectional view taken along line XIIa-XIIa in FIG. [Figure 13]FIG. 13 is a partial perspective view showing a state after the tip end portion of the first connection portion of the current collector has been crimped in the first modification. [Figure 14] FIG. 14 is a cross-sectional perspective view taken along line XIV-XIV in FIG. [Figure 15] FIG. 15 is a perspective view that illustrates a schematic configuration of a current collector in the second modification. [Figure 16] FIG. 16 is a partial perspective view showing a state in which a current collector is sandwiched between exposed portions of an electrode assembly in the second modification. [Figure 17A] FIG. 17A is a cross-sectional perspective view taken along line XVIIa-XVIIa in FIG. [Figure 17B] FIG. 17B is a cross-sectional view taken along line XVIIa-XVIIa in FIG. [Figure 18] FIG. 18 is a partial perspective view showing a state after the tip end portion of the first connection portion of the current collector has been crimped in Modification 2. As shown in FIG. [Figure 19] FIG. 19 is a cross-sectional perspective view taken along line XIX-XIX in FIG. [Figure 20] FIG. 20 is a perspective view that illustrates a schematic configuration of a current collector in the third modification. [Figure 21] FIG. 21 is a perspective view showing a state in which a current collector is inserted between two electrode assemblies in Modification 3. As shown in FIG. [Figure 22] FIG. 22 is a partial perspective view showing a state in which a current collector is sandwiched between exposed portions of an electrode assembly in Modification 3. As shown in FIG. [Figure 23A] FIG. 23A is a cross-sectional perspective view taken along line XXIIIa-XXIIIa in FIG. [Figure 23B] FIG. 23B is a cross-sectional view taken along line XXIIIa-XXIIIa in FIG. [Figure 24] FIG. 24 is a partial perspective view showing a state after the tip end portion of the first connection portion of the current collector has been crimped in Modification 3. As shown in FIG. [Diagram 25] FIG. 25 is a cross-sectional perspective view taken along line XXV-XXV in FIG. [Figure 26]FIG. 26 is a perspective view showing a schematic configuration of a current collector in the fourth modification. [Figure 27] FIG. 27 is a perspective view showing a state in which a current collector is inserted between two electrode assemblies in the fourth modification. [Figure 28] FIG. 28 is a partial perspective view showing a state in which a current collector is sandwiched between exposed portions of an electrode assembly in Modification 4. As shown in FIG. [Figure 29A] FIG. 29A is a cross-sectional perspective view taken along line XXIXa-XXIXa in FIG. [Figure 29B] FIG. 29B is a cross-sectional view taken along line XXIXa-XXIXa in FIG. [Diagram 30] FIG. 30 is a partial perspective view showing a state after the tip end portion of the first connection portion of the current collector has been crimped in the fourth modification. [Diagram 31] FIG. 31 is a cross-sectional perspective view taken along line XXXI-XXXI in FIG. [Figure 32A] FIG. 32A is a diagram showing the configuration of a current collector in another embodiment, and is a partial cross-sectional view enlarging the vicinity of an external terminal on the positive electrode side. [Figure 32B] FIG. 32B is a cross-sectional view taken along line XXXIIb-XXXIIb in FIG. 32A. [Diagram 33] FIG. 33 is a partial perspective view showing the configuration of an electrode assembly and a current collector in another embodiment. [Figure 34A] 34A is a cross-sectional perspective view taken along line XXXIVa-XXXIVa in FIG. 33. FIG. [Figure 34B] FIG. 34B is a cross-sectional view taken along line XXXIVa-XXXIVa in FIG. [Diagram 35] FIG. 35 is a partial perspective view showing a state after the tip end portion of the first connection portion of the current collector has been crimped in another embodiment. [Diagram 36] FIG. 36 is a cross-sectional perspective view taken along line XXXVI-XXXVI in FIG. [Figure 37] FIG. 37 is a partial cross-sectional view showing a current collecting structure of a conventional secondary battery. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the following embodiments. In addition, appropriate modifications are possible within the scope of the effects of the present disclosure.

[0011] 1A and 1B are diagrams illustrating a schematic configuration of a prismatic secondary battery in one embodiment of the present disclosure, where FIG. 1A is a top view and FIG. 1B is a cross-sectional view taken along line Ib-Ib in FIG. 1A.

[0012] As shown in Figs. 1A and 1B, in a prismatic secondary battery 1 in this embodiment, an electrode assembly 10, which is a power generating element, is housed in a prismatic battery case 11 together with an electrolyte. The electrode assembly 10 has a structure in which a positive electrode plate and a negative electrode plate are laminated with separators (neither shown) interposed therebetween. The positive electrode plate has a positive electrode active material layer provided on the surface of a positive electrode core material, and the negative electrode plate has a negative electrode active material layer provided on the surface of a negative electrode core material. The opening of the battery case 11 is sealed with a sealing plate 12.

[0013] The positive electrode plate and the negative electrode plate each have exposed portions 10a, 10b on which no active material layer is formed at the end sides in the longitudinal direction L of the sealing plate 12. The exposed portions 10a, 10b extend in opposite directions in the longitudinal direction of the sealing plate 12 and are connected to the positive and negative current collectors 20A, 20B. Specifically, a plurality of exposed portions 10a, 10b are joined to the current collectors 20A, 20B in a bundled state. The joining can be performed by, for example, laser welding. On the outside of the sealing plate 12, positive and negative external terminals 30A, 30B connected to the positive and negative current collectors 20A, 20B, respectively, are provided. The electrode body 10 and the current collectors 20A, 20B are wrapped in an insulating holder 50 and housed in the battery case 11.

[0014] The materials of the current collectors 20A and 20B are not particularly limited as long as they are made of materials that are not corroded by the positive electrode potential and the negative electrode potential in the electrolyte. In addition, it is preferable that the positive and negative current collectors 20A and 20B are made of the same material as the exposed portion 10a of the positive electrode plate and the exposed portion 10b of the negative electrode plate, respectively. For example, in the case of a lithium ion secondary battery, it is preferable that the current collector (positive electrode current collector) 20A connected to the exposed portion 10a of the positive electrode plate is made of aluminum or an aluminum alloy, and the current collector (negative electrode current collector) 20B connected to the exposed portion 10b of the negative electrode plate is made of copper or a copper alloy.

[0015] 2 is a perspective view showing a schematic configuration of the positive electrode side current collector 20A. The negative electrode side current collector 20B has a similar configuration. In the following description, unless otherwise specified, the current collecting structure including the negative electrode side current collector 20B will be omitted.

[0016] As shown in FIG. 2, the current collector 20A includes a cylindrical first connection portion 21A and a plate-like second connection portion 22A, which are integrally formed of the same member. The second connection portion 22A has a first side surface 22a parallel to the longitudinal direction L of the sealing plate 12 and a second side surface 22b parallel to the width direction W of the sealing plate 12 and facing the electrode body 10. In this embodiment, the second side surface 22b has a curved shape with a protruding central portion, but may have a flat shape. In addition, the end portion of the second connection portion 22A on the first connection portion 21A side has an upper surface 22c parallel to the sealing plate 12.

[0017] In this embodiment, second connection portion 22A has a substantially U-shaped cross section along a direction parallel to sealing plate 12. The axis of first connection portion 21A having a cylindrical shape and first side surface 22a of second connection portion 22A overlap with each other in the width direction of sealing plate 12.

[0018] The current collector 20A having such a configuration can be manufactured, for example, by rolling, etc. Alternatively, the first connection portion 21A and the second connection portion 22A may be manufactured as separate parts, and then these may be integrated by welding, etc.

[0019] 1B, the first connection portion 21A penetrates from the inside to the outside of the sealing plate 12 through a through-hole provided in each of the first insulating member 40A arranged on the inside of the sealing plate 12, the sealing plate 12, the second insulating member 41A provided on the outside of the sealing plate 12, and the external terminal 30A. The tip of the first connection portion 21A is crimped and connected to the external terminal 30A, and the current collector 20A and the external terminal 30A are fixed to the sealing plate 12. Here, the current collector 20A is insulated from the sealing plate 12 by the first insulating member 40A, and the external terminal 30A is insulated from the sealing plate 12 by the second insulating member 41A.

[0020] Next, a procedure for assembling the prismatic secondary battery 1 in this embodiment will be described with reference to FIGS.

[0021] First, as shown in Fig. 3, two electrode bodies 10A, 10B and positive and negative current collectors 20A, 20B having the same structure are prepared. The electrode bodies 10A, 10B have positive and negative exposed portions 10a, 10b at both ends of the sealing plate 12 in the longitudinal direction L, respectively. The current collectors 20A, 20B have a configuration as shown in Fig. 2. Then, the current collectors 20A, 20B arranged at both ends of the sealing plate 12 in the longitudinal direction L are sandwiched between the exposed portions 10a, 10a of the electrode bodies 10A, 10B from the direction of the arrows in the figure.

[0022] Fig. 4 is a partial perspective view showing a state in which a current collector 20A is sandwiched between exposed portions 10a, 10a of electrode bodies 10A, 10B. Also, Fig. 5A is a cross-sectional perspective view taken along line Va-Va in Fig. 4, and Fig. 5B is a cross-sectional view.

[0023] As shown in Fig. 5B, the second connection portion 22A abuts against the exposed portions 10a, 10a of the electrode bodies 10A, 10B at first side surfaces 22a, 22a parallel to the longitudinal direction L of the sealing plate 12. Then, as shown in Fig. 4, the exposed portions 10a, 10a and the second connection portion 22A are joined by, for example, laser welding at joining regions 24 at the abutting portions.

[0024] Next, as shown in Fig. 6, the first insulating member 40A, the sealing plate 12, the second insulating member 41A, and the external terminal 30A are arranged in this order above the current collector 20A to which the electrode bodies 10A and 10B are connected. Here, the first insulating member 40A, the sealing plate 12, the second insulating member 41A, and the external terminal 30A are arranged with the axes of the through holes 40a, 12a, 41a, and 30a provided in each of them aligned. Then, the first connection portion 21A of the current collector 20A is passed through the through holes 40a, 12a, 41a, and 30a provided in the first insulating member 40A, the sealing plate 12, the second insulating member 41A, and the external terminal 30A in the direction of the arrow.

[0025] Fig. 7 is a partial perspective view showing a state after the tip of the first connection portion 21A protruding from the through hole 30a of the external terminal 30A has been crimped, and Fig. 8 is a cross-sectional perspective view taken along line VII-VII in Fig. 7.

[0026] 7 and 8, by crimping the tip of the first connection portion 21A, the first connection portion 21A is connected to the external terminal 30A, and the current collector 20A and the external terminal 30A are fixed to the sealing plate 12. In addition, the first insulating member 40A disposed on the inner side of the sealing plate 12 is fixed to the sealing plate 12 by being pressed by an upper surface 22c (see FIG. 2) of the second connection portion 22A on the first connection portion 21A side.

[0027] After the tip of the first connection portion 21A is crimped, the peripheral edge of the first connection portion 21A and the external terminal 30A may be fused and joined by, for example, laser welding, thereby further reducing the electrical resistance between the current collector 20A and the external terminal 30A.

[0028] Next, as shown in Fig. 9, the sealing plate 12 to which the current collector 20A and the external terminal 30A are integrally fixed is inserted into an insulating holder 50. Then, the electrode bodies 10A, 10B and the current collector 20A wrapped in the insulating holder 50 are housed in a battery case 11. Thereafter, the open end of the battery case 11 and the outer periphery of the sealing plate 12 are welded, for example, by laser welding, to seal the battery case 11. Finally, an electrolyte is injected into the battery case 11 through an injection hole (not shown) provided in the sealing plate 12, and the injection hole is then sealed with a plug 70 (see Figs. 1A and 1B).

[0029] As described above, in this embodiment, the first connection portion 21A of the current collector 20A penetrates the through holes 12a, 30a provided in the sealing plate 12 and the external terminal 30A from the inside to the outside of the sealing plate 12, and the tip of the first connection portion 21A is crimped to connect to the external terminal 30A, and the current collector 20A and the external terminal 30A are fixed to the sealing plate 12. That is, the tip of the first connection portion 21A of the current collector 20A is crimped to protrude outside the sealing plate 12. As a result, compared to the conventional case in which the tip of the cylindrical portion of the external terminal is crimped to protrude inside the sealing plate, it is not necessary to provide a certain distance required for crimping between the crimping portion and the electrode body 10A. Therefore, the distance between the sealing plate 140 and the electrode body 110 can be reduced.

[0030] In addition, since the first connection portion 21A and the second connection portion 22A are integrally configured, when the tip portion of the first connection portion 21A is crimped to protrude outside the sealing plate 12, the first insulating member 40A arranged inside the sealing plate 12 is pressed by the upper surface 22c of the second connection portion 22A and fixed to the sealing plate 12. Therefore, only the first insulating member 40A exists between the sealing plate 12 and the second connection portion 22A. This allows the electrode body 10 connected to the second connection portion 22A to be brought close to the first insulating member 40A without contacting it, including manufacturing tolerances.

[0031] In this manner, in this embodiment, the gap between the sealing plate 140 and the electrode body 110 can be reduced, making it possible to provide a secondary battery having a current collection structure suitable for achieving higher capacity and higher energy density.

[0032] In addition to the above effects, even if the peripheral edge of the first connecting portion 21A and the external terminal 30A are melt-joined by laser welding or the like after the tip of the first connecting portion 21A is crimped in order to reduce the electrical resistance between the current collector 20A and the external terminal 30A, sputter residue from the laser welding will not enter the battery case 11 during the secondary battery assembly process. This makes it possible to provide a highly reliable secondary battery.

[0033] In this embodiment, the current collector 20A has the first connection portion 21A and the second connection portion 22A integrally formed from the same material. Here, the first connection portion 21A is connected to the external terminal 30A by crimping its tip, and therefore has a cylindrical structure. On the other hand, the second connection portion 22A is connected to an end edge of the electrode body 10 (positive electrode plate or negative electrode plate), and therefore the structure needs to have at least a side surface that is connected to the end edge of the electrode body 10.

[0034] For example, the current collector 20A illustrated in FIG. 2 is in the form of a plate having a first side surface 22a with a width in the longitudinal direction L of the sealing plate 12, and is connected to the edge of the electrode body 10 at the first side surface 22a.

[0035] However, the structure of the second connection part 22A is not limited thereto, and can be determined as appropriate, for example, depending on the required current collection characteristics, the configuration of the electrode body, etc. Various modified examples of the current collector 20A are exemplified below. Note that in all of the current collectors 20A exemplified below, the first connection part 21A connected to the external terminal 30A and the second connection part 22A connected to the edge of the positive or negative electrode plate are integrally formed from the same member.

[0036] (Variation 1) FIG. 10 is a perspective view that illustrates a schematic configuration of a current collector 20A in the first modification.

[0037] As shown in FIG. 10, the first connection portion 21A of the current collector 20A in this first modification is cylindrical, and the second connection portion 22A is block-shaped with a thickness in the width direction W of the sealing plate 12.

[0038] The second connection portion 22A has a first side surface 22a parallel to the longitudinal direction L of the sealing plate 12 and a second side surface 22b parallel to the width direction W of the sealing plate 12. In addition, the end portion of the second connection portion 22A on the first connection portion 21A side has an upper surface 22c parallel to the sealing plate 12.

[0039] Fig. 11 is a partial perspective view showing a state in which a current collector 20A is sandwiched between exposed portions 10a, 10a of electrode assemblies 10A, 10B. Also, Fig. 12A is a cross-sectional perspective view taken along line XIIa-XIIa in Fig. 11, and Fig. 12B is a cross-sectional view.

[0040] As shown in Fig. 12B, the second connection portion 22A abuts against the exposed portions 10a, 10a of the electrode bodies 10A, 10B at the first side surfaces 22a, 22a. Then, as shown in Fig. 1, the exposed portions 10a, 10a and the second connection portion 22A are joined by laser welding or the like at joining regions 24 at the abutting portions.

[0041] Fig. 13 is a partial perspective view showing a state after the first connecting portion 21A of the current collector 20A is inserted through the first insulating member 40A, the sealing plate 12, the second insulating member 41A, and the through holes provided in the external terminal 30A, and the tip of the first connecting portion 21A protruding from the through hole 30a of the external terminal 30A is crimped, similar to that shown in Fig. 6. Fig. 14 is a perspective view of a cross section taken along the line XIV-XIV in Fig. 13.

[0042] 13 and 14, by crimping the tip of the first connection portion 21A, the first connection portion 21A is connected to the external terminal 30A, and the current collector 20A and the external terminal 30A are fixed to the sealing plate 12. In addition, the first insulating member 40A disposed on the inner side of the sealing plate 12 is fixed to the sealing plate 12 by being pressed by the upper surface 22c of the second connection portion 22A on the first connection portion 21A side.

[0043] In this first modification, the cross-sectional area of ​​the second connection part 22A of the current collector 20A can be increased by forming the second connection part 22A in a block shape. This reduces the electrical resistance of the second connection part 22A, so that even if a large current flows through the current collector 20A, the generation of Joule heat can be suppressed. As a result, the temperature rise inside the battery can be suppressed.

[0044] (Variation 2) FIG. 15 is a perspective view that illustrates a schematic configuration of a current collector 20A in the second modification.

[0045] 15, the first connection portion 21A of the current collector 20A in this modification 2 has a cylindrical shape, and the second connection portion 22A has a plate shape parallel to the width direction W of the sealing plate 12. In addition, the second connection portion 22A has an upper plate portion 23A parallel to the sealing plate 12 at its end on the first connection portion 21A side.

[0046] Fig. 16 is a partial perspective view showing a state in which a current collector 20A is sandwiched between electrode assemblies 10A and 10B. Also, Fig. 17A is a cross-sectional perspective view taken along line XVIIb-XVIIb in Fig. 16, and Fig. 17B is a cross-sectional view.

[0047] 17B, ​​exposed portions 10a, 10a of electrode bodies 10A, 10B are each bent in the width direction of sealing plate 12 and abut against a side surface of second connecting portion 22A that is parallel to width direction W of sealing plate 12. Then, as shown in Fig. 16, exposed portions 10a, 10a and second connecting portion 22A are joined by laser welding or the like in joining regions 24 at the abutting sites.

[0048] Fig. 18 is a partial perspective view showing a state after the first connection portion 21A of the current collector 20A is inserted through the first insulating member 40A, the sealing plate 12, the second insulating member 41A, and the through holes provided in the external terminal 30A, and the tip portion of the first connection portion 21A protruding from the through hole 30a of the external terminal 30A is crimped, similar to that shown in Fig. 6. Fig. 19 is a perspective view of a cross section taken along the line XIX-XIX in Fig. 18.

[0049] 18 and 19, by crimping the tip of the first connection portion 21A, the first connection portion 21A is connected to the external terminal 30A, and the current collector 20A and the external terminal 30A are fixed to the sealing plate 12. In addition, the first insulating member 40A disposed on the inner side of the sealing plate 12 is fixed to the sealing plate 12 by being pressed by the upper plate portion 23A of the second connection portion 22A.

[0050] (Variation 3) FIG. 20 is a perspective view that illustrates a schematic configuration of a current collector 20A in the third modification.

[0051] In the above embodiment, the electrode bodies 10A and 10B have a structure in which the positive and negative electrode plates are stacked with a separator interposed therebetween, but the positive and negative electrode plates may be wound with a separator interposed therebetween. The current collector 20A in this modification 3 has a suitable configuration for the electrode bodies 10A and 10B having a wound structure.

[0052] As shown in FIG. 20, a first connection portion 21A of a current collector 20A in the present modified example 3 has a cylindrical shape, and a second connection portion 22A has a block shape and is made up of a first portion 22Aa and a second portion 22Ab having different widths.

[0053] The second portion 22Ab has a first side surface 22a parallel to the longitudinal direction L of the sealing plate 12. The first and second portions 22Aa, 22Ab have second side surfaces 22b parallel to the width direction W of the sealing plate 12. The end portion of the first portion 22Aa on the first connection portion 21A side has an upper surface 22c parallel to the sealing plate 12.

[0054] FIG. 21 is a perspective view showing a state in which two electrode assemblies 10A, 10B are arranged side by side and the current collector 20A shown in FIG. 20 is inserted between the two electrode assemblies 10A, 10B in the direction of the arrow.

[0055] The electrode bodies 10A and 10B have a structure in which a positive electrode plate and a negative electrode plate are wound with a separator interposed therebetween, and have a plurality of exposed portions 10a at the end in the winding axis direction. The plurality of exposed portions 10a are compressed in a bundled state in a certain region P in a direction perpendicular to the winding axis. Between the two exposed portions 10a, 10a on one side (upper side in FIG. 21) of the region P, there is a certain gap S1, and the two exposed portions 10a, 10a on the other side (lower side in FIG. 21) are in contact with each other. In addition, between the two exposed portions 10a, 10a in the region P, there is a certain gap S2 larger than the gap S1.

[0056] Fig. 22 is a partial perspective view showing a state in which a current collector 20A is sandwiched between exposed portions 10a, 10a of electrode assemblies 10A, 10B. Also, Fig. 23A is a cross-sectional perspective view taken along line XXIIIa-XXIIIa in Fig. 22, and Fig. 23B is a cross-sectional view.

[0057] As shown in Figure 22, the current collector 20A is sandwiched between the exposed portions 10a, 10a of the electrode bodies 10A, 10B with the first portion 22Aa of the second connection portion 22A inserted into the gap S1 shown in Figure 21, and the second portion 22Ab is sandwiched between the exposed portions 10a, 10a of the electrode bodies 10A, 10B with the second portion 22Ab inserted into the gap S2 shown in Figure 21.

[0058] 23A and 23B, the second portion 22Ab abuts against the exposed portions 10a, 10a of the electrode bodies 10A, 10B at the first side surfaces 22a, 22a. The exposed portions 10a, 10a and the second connection portion 22A are joined by laser welding or the like at joining regions 24 in the abutting portions.

[0059] Fig. 24 is a partial perspective view showing a state after the first connecting portion 21A of the current collector 20A is inserted through the first insulating member 40A, the sealing plate 12, the second insulating member 41A, and the through holes provided in the external terminal 30A, and the tip of the first connecting portion 21A protruding from the through hole 30a of the external terminal 30A is crimped, similar to that shown in Fig. 6. Fig. 25 is a perspective view of a cross section taken along the line XXIV-XXIV in Fig. 24.

[0060] 24 and 25, by crimping the tip of the first connection portion 21A, the first connection portion 21A is connected to the external terminal 30A, and the current collector 20A and the external terminal 30A are fixed to the sealing plate 12. In addition, the first insulating member 40A disposed on the inner side of the sealing plate 12 is fixed to the sealing plate 12 by being pressed by the upper surface 22c on the first connection portion 21A side of the second connection portion 22A.

[0061] (Variation 4) FIG. 26 is a perspective view that illustrates a schematic configuration of a current collector 20A in the fourth modification.

[0062] The current collector 20A in the present modification 4 also has a configuration suitable for the electrode assemblies 10A and 10B having a wound structure.

[0063] 26, the first connection portion 21A of the current collector 20A in this modification 4 has a cylindrical shape, and the second connection portion 22A has a plate-shaped first portion 22Aa and a second portion 22Ab having a substantially U-shaped cross section. The second connection portion 22A has an upper plate portion 23A at its end on the first connection portion 21A side. The second portion 22Ab has a first side surface 22a parallel to the longitudinal direction L of the sealing plate 12. Furthermore, the second connection portion 22A has an upper plate portion 23A at its end on the first connection portion 21A side.

[0064] FIG. 27 is a perspective view showing a state in which two electrode assemblies 10A, 10B are arranged side by side and the current collector 20A shown in FIG. 26 is inserted between the two electrode assemblies 10A, 10B in the direction of the arrow.

[0065] The electrode bodies 10A and 10B have a structure in which a positive electrode plate and a negative electrode plate are wound with a separator interposed therebetween, and have a plurality of exposed portions 10a at the end portions in the winding axis direction. The plurality of exposed portions 10a are compressed in a bundled state in a certain region P in a direction perpendicular to the winding axis. The two exposed portions 10a, 10a on both sides of the region P are in contact with each other. In addition, there is a certain gap S2 between the two exposed portions 10a, 10a in the region P.

[0066] Fig. 28 is a partial perspective view showing a state in which a current collector 20A is sandwiched between exposed portions 10a, 10a of electrode assemblies 10A, 10B. Also, Fig. 29A is a cross-sectional perspective view taken along line XXIXa-XXIXa in Fig. 28, and Fig. 29B is a cross-sectional view.

[0067] As shown in FIG. 28, the current collector 20A is sandwiched between the exposed portions 10a, 10a of the electrode bodies 10A, 10B with the second portion 22Ab of the second connection portion 22A inserted into the gap S2 shown in FIG.

[0068] 29A and 29B, the second portion 22Ab abuts against the exposed portions 10a, 10a of the electrode bodies 10A, 10B at the first side surfaces 22a, 22a. The exposed portions 10a, 10a and the second connection portion 22A are joined by laser welding or the like at joining regions 24 in the abutting portions.

[0069] Fig. 30 is a partial perspective view showing a state after the first connecting portion 21A of the current collector 20A is inserted through the first insulating member 40A, the sealing plate 12, the second insulating member 41A, and the respective through holes provided in the external terminal 30A, and the tip end portion of the first connecting portion 21A protruding from the through hole 30a of the external terminal 30A is crimped, similar to that shown in Fig. 6. Fig. 31 is a perspective cross-sectional view taken along the line XXXI-XXXI in Fig. 30.

[0070] 30 and 31, by crimping the tip of the first connection portion 21A, the first connection portion 21A is connected to the external terminal 30A, and the current collector 20A and the external terminal 30A are fixed to the sealing plate 12. In addition, the first insulating member 40A disposed on the inner side of the sealing plate 12 is fixed to the sealing plate 12 by being pressed by the upper plate portion 23A of the second connection portion 22A.

[0071] Although the present disclosure has been described above with reference to the preferred embodiments, such description is not intended to be limiting, and various modifications are possible.

[0072] For example, when the current collector 20A has the structure shown in Fig. 2, an insulating member 60 may be disposed on the second side surface 22b of the second connection portion 22A that faces the electrode body 10A, as shown in Fig. 32A and Fig. 32B. Here, Fig. 32A is a partial cross-sectional view enlarging the vicinity of the positive electrode external terminal 30A, and Fig. 32B is a cross-sectional view taken along line XXXIIb-XXXIIb in Fig. 32A.

[0073] The positive electrode collector 20A is connected to an exposed portion (positive electrode core material) exposed at the edge of the positive electrode plate at the first side surface 22a of the second connection portion 22A. Since a negative electrode plate is usually arranged on the outermost layer of the electrode body 10A, the second side surface 22b of the second connection portion 22A facing the electrode body 10A is located close to the negative electrode plate on the outermost layer of the electrode body 10A. If the secondary battery receives an impact from the outside, the second side surface 22b of the second connection portion 22A may break through the separator and come into contact with the negative electrode on the outermost layer, causing an internal short circuit between the positive electrode plate and the negative electrode plate. Therefore, by arranging an insulating member 60 on the second side surface 22b of the second connection portion 22A facing the electrode body 10A, it is possible to prevent such an internal short circuit from occurring. The insulating member 60 may be, for example, an insulating tape or an insulating coating film. Moreover, such an arrangement of the insulating member 60 can also be applied to current collectors having a structure other than that illustrated in FIG.

[0074] In the above embodiment, as shown in Fig. 4, Fig. 11, Fig. 16, Fig. 22, and Fig. 28, the second connection portion 22A and the exposed portion 10a of the current collector 20A are welded to each other at the joint region 24, but the joint may be covered with a covering member. This can prevent metal powder generated during welding from penetrating into the electrode body 10A. For example, an insulating tape or the like can be used as the covering member.

[0075] Furthermore, in the above embodiment, two electrode bodies 10A, 10B having the same structure are arranged in the battery case 11, but it is also possible to arrange only one electrode body.

[0076] Fig. 33 is a partial perspective view showing a state in which a current collector 20A is connected to an end edge of an electrode body 10A. Fig. 34A is a cross-sectional perspective view taken along line XXXIVa-XXXIVa in Fig. 33, and Fig. 34B is a cross-sectional view. Here, the current collector 20A has the structure shown in Fig. 2.

[0077] 34A and 34B, the electrode body 10A has multiple exposed portions 10a at the longitudinal direction L end of the sealing plate 12, and the multiple exposed portions 10a are bundled together at the width direction W end side of the sealing plate 12. The second connection portion 22A abuts against the exposed portions 10a of the electrode body 10A at a first side surface 22a parallel to the longitudinal direction L of the sealing plate 12. Then, at the abutting portion, the exposed portions 10a and the second connection portion 22A are joined by laser welding or the like.

[0078] Fig. 35 is a partial perspective view showing a state after the first connecting portion 21A of the current collector 20A is inserted through the through holes provided in the first insulating member 40A, the sealing plate 12, the second insulating member 41A, and the external terminal 30A, and the tip of the first connecting portion 21A protruding from the through hole 30a of the external terminal 30A is crimped, similar to that shown in Fig. 6. Fig. 36 is a perspective view of a cross section taken along the line XXXVI-XXXVI in Fig. 35.

[0079] 35 and 36, by crimping the tip of the first connection portion 21A, the first connection portion 21A is connected to the external terminal 30A, and the current collector 20A and the external terminal 30A are fixed to the sealing plate 12. In addition, the first insulating member 40A disposed on the inner side of the sealing plate 12 is fixed to the sealing plate 12 by being pressed by the upper surface 22c on the first connection portion 21A side of the second connection portion 22A.

[0080] In the above embodiment, the second connection portion 22A is exemplified as a substantially rectangular parallelepiped block as shown in Figs. 10 and 20, but the block may be, for example, cylindrical.

[0081] In addition, in the above embodiment, as shown in Figures 4, 11, 25, and 31, the axis of the cylindrical first connection portion 21A and the first side surface 22a of the second connection portion 22A are overlapped with each other in the width direction of the sealing plate 12, but the two do not necessarily have to overlap.

[0082] The prismatic secondary battery of this embodiment can be manufactured by the following steps (a) to (d).

[0083] First, a current collector 20A is prepared in which a cylindrical first connection portion 21A and a plate-like or block-like second connection portion 22A are integrally formed from the same member (step (a)).

[0084] Next, an edge of a positive electrode plate or a negative electrode plate is connected to the second connection portion 22A of the current collector 20A. After that, the sealing plate 12 and the external terminal 30A are disposed above the current collector 20A (step (b)).

[0085] Next, the first connection portion 21A of the current collector 20A is penetrated through holes provided in the sealing plate 12 and the external terminal 30A (step (c)).

[0086] Thereafter, the tip of the first connection portion 21A is crimped to connect the first connection portion 21A to the external terminal 30A, and the current collector 20A and the external terminal 30A are fixed to the sealing plate 12 (step (d)).

[0087] After step (d), the peripheral edge of the first connection portion 21A and the external terminal 30A may be welded together, for example, by a laser or the like (step (e)).

[0088] The type of the prismatic secondary battery in this embodiment is not particularly limited, but it can be applied to, for example, a lithium ion secondary battery, a nickel hydrogen secondary battery, and the like. [Explanation of symbols]

[0089] 1 Prismatic secondary battery 10A,10B electrode body 10a,10b Exposed part 11 Battery case 12 Sealing plate 12a Through hole 20A, 20B Current collector 21A 1st Connection 22A 2nd Connection 22Aa 1st part 22Ab 2nd site 22a 1st side 22b Second side 22c top surface 23A Upper plate 24 Joint area 30A,30B external terminal 30a through hole 40A First insulating member 41A Second insulating member 50 Insulating holder 60 Insulating materials

Claims

1. An electrode assembly including a positive electrode plate and a negative electrode plate; a rectangular battery case having an opening and housing the electrode assembly; a sealing plate that seals the opening; a current collector connected to an end side of the positive electrode plate or the negative electrode plate at a longitudinal end of the sealing plate; an external terminal provided on the outside of the sealing plate and connected to the current collector; A prismatic secondary battery comprising: the current collector is configured such that a first connection portion connected to the external terminal and a second connection portion connected to an end side of the positive electrode plate or the negative electrode plate are integrally formed from the same member, the first connection portion passes through a through hole provided in the sealing plate and the external terminal from the inside to the outside of the sealing plate, and a tip end of the first connection portion is crimped to be connected to the external terminal, and the current collector and the external terminal are fixed to the sealing plate, The first connection portion has a cylindrical shape, the second connection portion has a first side surface parallel to a longitudinal direction of the sealing plate, The current collector is connected to an end edge of the positive electrode plate or the negative electrode plate at the first side surface, an axis of the first connection portion having a cylindrical shape and the first side surface of the second connection portion overlap with each other in a width direction of the sealing plate, the second connection portion has a second side surface that is parallel to a width direction of the sealing plate and perpendicular to a longitudinal direction of the sealing plate and faces the electrode body; An insulating member is disposed on the second side surface.

2. A rectangular secondary battery as described in claim 1, wherein the second connection portion is plate-shaped or block-shaped.

3. The second connection portion of the current collector and an end edge of the positive electrode plate or the negative electrode plate are welded to each other, The prismatic secondary battery according to claim 1 , wherein the welded joint is covered with a covering member.

4. The electrode body is composed of a plurality of 4. The prismatic secondary battery according to claim 1, wherein an end side of the positive electrode plate or the negative electrode plate of each electrode body is connected to a common current collector.

5. An electrode assembly including a positive electrode plate and a negative electrode plate; a rectangular battery case having an opening and housing the electrode assembly; a sealing plate that seals the opening; a current collector connected to an end side of the positive electrode plate or the negative electrode plate at a longitudinal end of the sealing plate; an external terminal provided on the outside of the sealing plate and connected to the current collector; A method for manufacturing a prismatic secondary battery comprising: (a) preparing a current collector in which a first connection portion having a cylindrical shape and a second connection portion having a plate or block shape are integrally formed from the same material; connecting an end edge of the positive electrode plate or the negative electrode plate to the second connection portion of the current collector; a step (b) of disposing the sealing plate and the external terminal above the current collector; (c) a step of penetrating the first connection portion of the current collector into through holes provided in the sealing plate and the external terminal; a step (d) of crimping a tip end of the first connection portion to connect the first connection portion to the external terminal and fix the current collector and the external terminal to the sealing plate; Including, The first connection portion has a cylindrical shape, the second connection portion has a first side surface parallel to a longitudinal direction of the sealing plate, The current collector is connected to an end edge of the positive electrode plate or the negative electrode plate at the first side surface, an axis of the first connection portion having a cylindrical shape and the first side surface of the second connection portion overlap with each other in a width direction of the sealing plate, the second connection portion has a second side surface that is parallel to the width direction of the sealing plate and perpendicular to the longitudinal direction of the sealing plate and faces the electrode body; an insulating member is disposed on the second side surface.

6. The method for producing a prismatic secondary battery according to claim 5 , further comprising, after the step (d), a step (e) of welding a peripheral edge portion of the first connection portion and the external terminal.

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