Secondary batteries

Abstract

The present invention provides a secondary battery that can reduce the impact on electrode terminals by ejected material from the pressure relief valve while suppressing the enlargement of the exhaust path for the gas discharged from the pressure relief valve. [Solution] The secondary battery 10 comprises an electrode body 100, a housing that houses the electrode body 100, a positive electrode terminal 620 and a negative electrode terminal 520. The housing includes a cylindrical main body portion 210 with a first opening 215 and a second opening 216 on both sides in the longitudinal direction, a first sealing body 510 that closes the first opening 215, and a second sealing body 610 that closes the second opening 216. The main body portion 210 has a pair of long sides and a pair of short sides 213, 214 that face each other in the short direction perpendicular to the longitudinal direction. The electrode body 100 includes a negative electrode current collector portion 110N located at one end in the longitudinal direction and a positive electrode current collector portion 110P located at the other end in the longitudinal direction. A single pressure relief valve 222 is provided on one of the short sides 213 of the pair of short sides.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a secondary battery, and particularly to a secondary battery mounted on a vehicle. BACKGROUND ART

[0002] As a conventional secondary battery, US Patent Application Publication No. 2022 / 0302533 (Patent Document 1) discloses a configuration in which, in a casing accommodating an electrode assembly, each opening of a case body that is open at both sides in the longitudinal direction is closed by a lid member provided with an external terminal, and a pressure relief valve is provided on each lid member. PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0003] Patent Document 1 US Patent Application Publication No. 2022 / 0302533 Specification SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0004] However, in the configuration of Patent Document 1, the pressure relief valves are provided on both side walls (lid members) of the casing located in the longitudinal direction perpendicular to the height direction. For this reason, when the pressure inside the casing increases and the pressure relief valve opens, not only gas but also electrolyte is ejected from the pressure relief valve. In such a case, there is a concern that the ejecta ejected from inside the casing will adhere to external terminals (electrode terminals) and the like, the external terminals will be electrically connected to metal members and the like arranged around them, and the secondary battery will be short-circuited.

[0005] Furthermore, because the housing is equipped with multiple pressure relief valves, if there are differences in the pressure released due to tolerances, etc., it becomes difficult to open multiple pressure relief valves simultaneously. For this reason, when multiple secondary batteries are arranged in a battery module, it becomes difficult to predict which pressure relief valve will release gas from each secondary battery. As a result, exhaust paths for exhausting gas ejected from the pressure relief valves must be provided on the outside of both side walls (lid members) of the housing, which leads to larger exhaust paths.

[0006] This disclosure has been made in view of the above-mentioned problems, and the purpose of this disclosure is to provide a secondary battery that can reduce the impact on electrode terminals by ejected material from the pressure relief valve while suppressing an increase in the size of the exhaust path for the gas discharged from the pressure relief valve. [Means for solving the problem]

[0007] A secondary battery according to this disclosure comprises an electrode body in which a positive electrode and a negative electrode are arranged side by side in a first direction, a housing for housing the electrode body, and a positive electrode terminal and a negative electrode terminal provided in the housing. The housing includes a cylindrical main body portion having a first opening and a second opening on both sides of the longitudinal direction of the housing perpendicular to the first direction, a first sealing body that closes the first opening, and a second sealing body that closes the second opening. The negative electrode terminal is provided in the first sealing body, and the positive electrode terminal is provided in the second sealing body. The main body portion has a pair of long sides facing the first direction and a pair of short sides facing the short direction of the housing perpendicular to the first direction and the longitudinal direction. The electrode body includes a negative electrode current collector portion located at one end in the longitudinal direction and electrically connected to the negative electrode terminal, and a positive electrode current collector portion located at the other end in the longitudinal direction and electrically connected to the positive electrode terminal. A single pressure relief valve is provided on one of the pair of short sides mentioned above.

[0008] According to the above configuration, when the pressure relief valve is opened, gas can be discharged from the pressure relief valve toward a preferred direction, i.e., toward one side of the short direction perpendicular to the first direction in which the positive and negative electrodes are aligned. Furthermore, the pressure relief valve is located on a short side different from the first sealing body on which the negative electrode terminal is located and the second sealing body on which the positive electrode terminal is located. This prevents ejected substances such as electrolyte from adhering to the electrode terminals, such as the positive and negative electrode terminals, and prevents unintentional electrical connection between the electrode terminals and surrounding metal components. This reduces the impact of ejected substances from the pressure relief valve on the electrode terminals. Moreover, since a single pressure relief valve is provided, the location from which the gas is discharged can be specified as one location. Therefore, when multiple secondary batteries are arranged in a row, the exhaust path for exhausting the gas discharged from the pressure relief valve does not need to be enlarged compared to a configuration with multiple pressure relief valves.

[0009] In the secondary battery based on the above disclosure, the pressure relief valve may be positioned at a distance in the longitudinal direction from both ends of one of the short sides, such that the distance from the short side is at least one-third of the length of the short side in the longitudinal direction.

[0010] With the above configuration, the pressure relief valve is positioned at a considerable distance in the longitudinal direction from the positive and negative terminals, further reducing the adhesion of ejected material to the positive and negative terminals.

[0011] In the secondary battery based on the above disclosure, the pressure relief valve may be provided in the center of one of the short sides in the longitudinal direction.

[0012] With the above configuration, since the pressure relief valve is positioned approximately midway between the positive and negative terminals, the adhesion of ejected material from the pressure relief valve to the positive and negative terminals can be further reduced.

[0013] The battery module based on this disclosure comprises a plurality of the above-mentioned secondary batteries, wherein the plurality of the above-mentioned secondary batteries are arranged in line in the first direction.

[0014] According to the above configuration, by providing a module in which a plurality of secondary batteries each provided with a single pressure release valve on a short side surface are arranged, the exhaust path can have a simpler configuration. Effects of the Invention

[0015] According to the present disclosure, it is possible to provide a secondary battery capable of reducing the influence of ejected substances ejected from a pressure release valve on electrode terminals while suppressing an increase in size of an exhaust path for gas discharged from the pressure release valve. Brief Description of the Drawings

[0016] [Figure 1] It is a perspective view of the secondary battery according to Embodiment 1. [Figure 2] It is an exploded perspective view of the secondary battery according to Embodiment 1. [Figure 3] It is a cross-sectional view along the line III-III shown in FIG. 1. [Figure 4] It is a cross-sectional view along the line IV-IV shown in FIG. 1. [Figure 5] It is a top view of the secondary battery according to Embodiment 1. [Figure 6] It is a top view of the secondary battery according to Embodiment 2. [Figure 7] It is a perspective view of the battery module according to Embodiment 3. Mode for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the embodiments shown below, the same or common portions are denoted by the same reference numerals in the drawings, and description thereof will not be repeated.

[0018] (Embodiment 1) FIG. 1 is a perspective view of the secondary battery according to Embodiment 1. FIG. 2 is an exploded perspective view of the secondary battery according to Embodiment 1. FIG. 3 is a cross-sectional view along the line III-III shown in FIG. 1.

[0019] As shown in FIGS. 1 to 3, the secondary battery 10 according to the first embodiment includes an electrode assembly 100, a case 200, a positive electrode member 620 serving as a positive electrode terminal, and a negative electrode member 520 serving as a negative electrode terminal.

[0020] The case 200 has a rectangular parallelepiped shape whose thickness in the thickness direction T is smaller than the width in the width direction W and the height in the height direction H. The thickness direction T is parallel to a first direction in which a positive electrode 110 (see FIG. 4) and a negative electrode 120 (see FIG. 4), which will be described later, are arranged side by side. The width direction W is orthogonal to the thickness direction T, and the height direction H is orthogonal to both the thickness direction T and the width direction W. The width of the case 200 in the width direction W is larger than the height of the case 200 in the height direction H. The width direction W is defined as the longitudinal direction of the case 200, and the height direction H is defined as the lateral direction of the case 200.

[0021] The case 200 houses the electrode assembly 100 and an electrolytic solution (not shown) therein. The case 200 includes a main body 210, a first sealing body 510, and a second sealing body 610.

[0022] The main body 210 has a cylindrical shape provided with a first opening 215 and a second opening 216 on both sides in the width direction W, respectively. More specifically, the main body 210 has a square cylindrical shape open at both sides in the width direction W. The first opening 215 is provided on one side in the width direction W, and the second opening 216 is provided on the other side in the width direction W. The main body 210 is made of a metal such as aluminum.

[0023] The main body 210 includes a pair of long sides 211 and 212 facing each other in the thickness direction T, and a pair of short sides 213 and 214 facing each other in the height direction H. One of the pair of short sides 213 and 214, the short side 213, is located on one side (upper side) in the height direction H. The short side 213 connects the ends of the pair of long sides 211 and 212 located on one side in the height direction H. The other short side 214 is located on the other side (downward side) in the height direction H. The other short side 214 connects the ends of the pair of long sides 211 and 212 located on the other side in the height direction H.

[0024] One of the shorter sides 213 is provided with a pressure relief valve 222 and an injection port 224. The pressure relief valve 222 is designed to rupture when the internal pressure of the housing 200 exceeds a predetermined pressure. When the pressure relief valve 222 ruptures, the gas inside the housing 200 is discharged to the outside, causing the internal pressure inside the housing 200 to decrease.

[0025] The electrolyte injection port 224 is sealed by a sealing member 225. The electrolyte injection port 224 is a through-hole for injecting electrolyte into the housing 200 during the manufacturing process of the secondary battery 10. The sealing member 225 is a member that seals the electrolyte injection port 224 after the electrolyte has been injected into the housing 200. The sealing member 225 may be, for example, a permeable membrane that allows gas to pass through but not liquid. In this case, when the gas generated during charging is discharged to the outside of the housing 200, the gas can be discharged through the permeable membrane. This eliminates the need to provide a separate gas vent. In addition, the permeable membrane can prevent the electrolyte from leaking to the outside of the housing 200. Note that the sealing member 225 is not limited to a permeable membrane, and resin members, metal members, etc. can be used as appropriate.

[0026] The first sealing body 510 closes the first opening 215. The first sealing body 510 has a flat plate shape. The first sealing body 510 is made of a metal such as aluminum. A negative electrode member 520 is provided on the first sealing body 510. The first sealing body 510 is fixed to the first opening 215 by, for example, laser welding.

[0027] The negative electrode member 520 is provided on the outer surface of the first sealing body 510. The negative electrode member 520 functions as a negative electrode terminal. The negative electrode member 520 includes a negative electrode terminal plate 521 and an insulating plate 522.

[0028] The negative electrode terminal plate 521 is formed in a substantially rectangular parallelepiped shape. The negative electrode terminal plate 521 is held by an insulating plate 522. The insulating plate 522 is fixed to the outer surface of the first sealing body 510. The insulating plate 522 insulates the first sealing body 510 from the negative electrode terminal plate 521. Both the negative electrode terminal plate 521 and the insulating plate 522 are provided with through holes for inserting the negative electrode connecting pin 533, which will be described later.

[0029] The second sealing body 610 closes the second opening 216. The second sealing body 610 has a flat plate shape. The second sealing body 610 is made of a metal such as aluminum. A positive electrode member 620 is provided on the second sealing body 610. The second sealing body 610 is fixed to the second opening 216 by, for example, laser welding.

[0030] The positive electrode member 620 is provided on the outer surface of the second sealing body 610. The positive electrode member 620 functions as a positive electrode terminal. The positive electrode member 620 includes a positive electrode terminal plate 621 and a terminal block 622.

[0031] The positive terminal plate 621 is formed in a rectangular parallelepiped shape. The positive terminal plate 621 is made of a metal such as aluminum.

[0032] The terminal block 622 is formed in a rectangular parallelepiped shape. The terminal block 622 is made of a different metal (such as iron) than the metal that makes up the positive terminal plate 621. The terminal block 622 is fixed to the outer surface of the second sealing body 610 by welding or the like. The positive terminal plate 621 is fixed to the terminal block 622 by welding or the like. The main body 210 and the second sealing body 610 are electrically connected to the positive terminal plate 621 via the terminal block 622 and are charged with the same polarity as the positive terminal plate 621. Each of the positive terminal plate 621 and the terminal block 622 has a through hole for inserting the positive connecting pin 633, which will be described later.

[0033] Furthermore, the positive electrode member 620 may have an insulating plate placed between it and the second sealing body 610, thereby electrically insulating the positive electrode member 620 from the second sealing body 610. In this case, the insulating plate may be placed in place of the terminal block 622, or the insulating plate may be placed between the terminal block 622 and the second sealing body 610.

[0034] The secondary battery 10 further includes a negative electrode connecting member 530, a negative electrode side first insulating member 540, a negative electrode side second insulating member 550, and an insulator 560 on the negative electrode member 520 side.

[0035] The negative electrode connecting member 530 connects the negative electrode current collector 110N and the negative electrode terminal plate 521. The negative electrode current collector 110N is a portion of the electrode body 100 formed by bundling together multiple negative electrode tabs 122n (see Figure 5), which will be described later. The negative electrode connecting member 530 includes a negative electrode side first current collector 531, a negative electrode side second current collector 532, and a negative electrode connecting pin 533.

[0036] The negative electrode side first current collector 531 is made of a thin plate-shaped conductive material. The negative electrode side first current collector 531 is connected to the negative electrode current collector 110N by laser welding or ultrasonic welding or the like.

[0037] The negative electrode side second current collector 532 is made of a thin plate-shaped conductive member. The negative electrode side second current collector 532 is connected to the negative electrode side first current collector 531 by laser welding or ultrasonic welding. The negative electrode side second current collector 532 has a holding portion 532a that holds the negative electrode connecting pin 533. The holding portion 532a has a flat plate shape. A through hole is provided in the holding portion 532a into which the base end of the negative electrode connecting pin 533 is inserted.

[0038] The negative electrode connecting pin 533 connects the negative electrode side second current collector 532 and the negative electrode terminal plate 521. The negative electrode connecting pin 533 includes a cylindrical portion. The tip of this cylindrical portion penetrates the first sealing body 510, the insulating plate 522, and the negative electrode terminal plate 521, and is crimped to the negative electrode terminal plate 521.

[0039] The negative electrode side first insulating member 540 has a substantially plate-like shape. The negative electrode side first insulating member 540 is positioned to contact the inner surface of the first sealing body 510. The negative electrode side first insulating member 540 is provided with a through hole 542 through which the negative electrode connecting pin 533 is inserted.

[0040] The negative electrode side second insulating member 550 is positioned between the negative electrode side first insulating member 540 and the electrode body 100. The negative electrode side second insulating member 550 is provided with a slit 552 through which the negative electrode current collector 110N is inserted.

[0041] The negative electrode side first insulating member 540 and the negative electrode side second insulating member 550 are assembled such that a accommodating space is formed between them. The negative electrode current collector 110N, the negative electrode side first current collector 531, and the negative electrode side second current collector 532 are arranged in this accommodating space, with the negative electrode current collector 110N inserted through the slit 552 being positioned within it.

[0042] The insulator 560 has a shape that covers the cylindrical portion of the negative electrode connecting pin 533. The insulator 560 insulates the negative electrode connecting pin 533 from the housing 200 (more specifically from the first sealing body 510).

[0043] The negative electrode member 520, the first sealing body 510, the negative electrode connecting member 530, the negative electrode side first insulating member 540, the negative electrode side second insulating member 550, and the insulator 560 are assembled to constitute the first lid assembly 50.

[0044] The first cover assembly 50 is fixed to the main body 210 by attaching the first sealing body 510 to the first opening 215 with the negative electrode current collector 110N and the negative electrode connecting member 530 fixed by welding or the like.

[0045] The secondary battery 10 further comprises a positive electrode connecting member 630, a positive electrode side first insulating member 640, a positive electrode side second insulating member 650, and an insulator 660 on the positive electrode member 620 side.

[0046] The positive electrode connecting member 630 connects the positive electrode current collector 110P and the positive electrode terminal plate 621. The positive electrode current collector 110P is a portion of the electrode body 100 formed by bundling together multiple positive electrode tabs 112p (see Figure 5), which will be described later. The positive electrode connecting member 630 includes a positive electrode side first current collector 631, a positive electrode side second current collector 632, and a positive electrode connecting pin 633.

[0047] The positive electrode side first current collector 631 is made of a thin plate-shaped conductive material. The positive electrode side first current collector 631 is connected to the positive electrode current collector 110P by laser welding or ultrasonic welding or the like.

[0048] The positive electrode side second current collector 632 is made of a thin plate-shaped conductive material. The positive electrode side second current collector 632 is connected to the positive electrode side first current collector 631 by laser welding or ultrasonic welding. The positive electrode side second current collector 632 has a holding portion 632a that holds the positive electrode connecting pin 633. The holding portion 632a has a flat plate shape. A through hole is provided in the holding portion 632a into which the base end of the positive electrode connecting pin 633 is inserted.

[0049] The positive electrode connecting pin 633 connects the positive electrode side second current collector 632 and the positive electrode terminal plate 621. The positive electrode connecting pin 633 includes a cylindrical portion. The tip of this cylindrical portion passes through the second sealing body 610, the terminal block 622, and the positive electrode terminal plate 621, and is crimped to the positive electrode terminal plate 621.

[0050] The positive electrode side first insulating member 640 has a substantially plate-like shape. The positive electrode side first insulating member 640 is positioned to contact the inner surface of the second sealing body 610. The positive electrode side first insulating member 640 is provided with a through hole 642 through which the positive electrode connecting pin 633 is inserted.

[0051] The positive electrode side second insulating member 650 is positioned between the positive electrode side first insulating member 640 and the electrode body 100. The positive electrode side second insulating member 650 is provided with a slit 652 through which the positive electrode current collector 110P is inserted.

[0052] The positive electrode side first insulating member 640 and the positive electrode side second insulating member 650 are assembled such that a accommodating space is formed between them. The positive electrode current collector 110P, the positive electrode side first current collector 631, and the positive electrode side second current collector 632 are arranged in this accommodating space, with the positive electrode current collector 110P inserted through the slit 652 being placed inside.

[0053] The insulator 660 has a shape that covers the cylindrical portion of the positive electrode connecting pin 633. The insulator 660 insulates the positive electrode connecting pin 633 from the housing 200 (more specifically from the second sealing body 610).

[0054] The positive electrode member 620, the second sealing body 610, the positive electrode connecting member 630, the positive electrode side first insulating member 640, the positive electrode side second insulating member 650, and the insulator 660 are assembled to constitute the second lid assembly 60.

[0055] The second cover assembly 60 is fixed to the main body 210 by attaching the second sealing body 610 to the second opening 216 with the positive electrode current collector 110P and the positive electrode connecting member 630 fixed together by welding or the like.

[0056] Figure 4 is a cross-sectional view along the line IV-IV shown in Figure 1. For convenience, the housing 200 of the secondary battery 10 is omitted in Figure 4, and only the electrode body 100 is shown. The details of the electrode body 100 will be explained with reference to Figure 4.

[0057] As shown in Figure 4, the electrode body 100 comprises a plurality of positive electrodes 110 and a plurality of negative electrodes 120, and a separator 130. The plurality of positive electrodes 110 and a plurality of negative electrodes 120 are arranged alternately in the thickness direction T, insulated by the separator 130.

[0058] Each negative electrode 120 is formed in a rectangular shape with the width direction W as the long side and the height direction H as the short side. Each negative electrode 120 has a negative electrode current collector foil 122 and a negative electrode active material layer 124 provided on both sides of the negative electrode current collector foil 122. As shown in Figure 4, the negative electrode current collector foil 122 has a negative electrode tab 122n (see Figure 5) on which the negative electrode active material layer 124 is not provided. The negative electrode tab 122n protrudes toward one side in the width direction W.

[0059] Each positive electrode 110 is formed in a rectangular shape with the width direction W as the long side and the height direction H as the short side. Each positive electrode 110 has a positive electrode current collector foil 112 and a positive electrode active material layer 114 provided on both sides of the positive electrode current collector foil 112 in the thickness direction T. The positive electrode current collector foil 112 has a positive electrode tab 112p (see Figure 5) on which the positive electrode active material layer 114 is not provided. The positive electrode tab 112p protrudes toward the other side in the width direction W.

[0060] The separator 130 insulates the positive electrode 110 and the negative electrode 120. The separator 130 is made of an insulating material and has minute voids that allow ion permeation. The separator 130 is formed in a zigzag pattern.

[0061] The separator 130 has a rectangular shape before being formed into a zigzag shape. The separator 130 is arranged between the positive electrode 110 and the negative electrode 120 while being formed into a zigzag shape. The separator 130 has a plurality of intervening portions 132a, a plurality of first folded portions 132b, a plurality of second folded portions 132c, and an outermost covering portion 132d.

[0062] Each intervening portion 132a is interposed between the positive electrode 110 and the negative electrode 120, which are adjacent to each other in the thickness direction T. In other words, each intervening portion 132a has the function of insulating the positive electrode 110 and the negative electrode 120. Each intervening portion 132a is composed of a rectangular region.

[0063] Each first folded portion 132b connects the ends of adjacent intervening portions 132a in the height direction H in the thickness direction T, such that the positive electrode 110 is positioned between them. The first folded portion 132b is positioned on one side (above) of the positive electrode 110 in the height direction H.

[0064] Each second folded portion 132c connects the other ends in the height direction H of adjacent intervening portions 132a in the thickness direction T, such that the negative electrode 120 is positioned between them. The second folded portion 132c is positioned on the other side (below) of the negative electrode 120 in the height direction H.

[0065] The outermost covering portion 132d covers each of the first folded portions 132b and each of the second folded portions 132c together. More specifically, the outermost covering portion 132d covers all of the positive electrodes 110, all of the negative electrodes 120, all of the intervening portions 132a, all of the first folded portions 132b and all of the second folded portions 132c together by winding them around a central axis parallel to the width direction W. The end portion 132e of the outermost covering portion 132d is set in a range that does not overlap with the positive electrode active material layer 114 and the negative electrode active material layer 124 in the thickness direction T. In this embodiment, the end portion 132e of the outermost covering portion 132d is provided below each of the positive electrodes 110 and each of the negative electrodes 120. Note that the circumferential and bottom surfaces of the multiple positive electrodes 110, multiple negative electrodes 120, and the separator 130 may be covered with an insulating film (not shown).

[0066] Figure 5 is a top view of the secondary battery according to Embodiment 1. The details of the arrangement of the pressure relief valve and the liquid injection port will be described with reference to Figure 5.

[0067] As shown in Figure 5, the pressure relief valve 222 and the liquid injection port 224 are located on one of the short sides 213. More specifically, the pressure relief valve 222 is positioned at a distance in the width direction W from both ends of the short side 213 in the width direction W, for a distance of at least one-third of the length of one of the short sides 213 in the width direction W.

[0068] In other words, when one short side 213 is equally divided into three regions, a first region R1, a second region R2, and a third region R3, starting from one side in the width direction W, the pressure relief valve 222 is located in the second region R2, which is situated between the first region R1 and the third region R3.

[0069] In this way, the pressure relief valve 222 is positioned a considerable distance away from the positive electrode member 620 and the negative electrode member 520 in the width direction W, thus reducing the likelihood of ejected material from the pressure relief valve 222 adhering to the positive electrode member 620 and the negative electrode member 520.

[0070] The electrolyte injection port 224 is also provided in the second region R2. This allows the electrolyte to be distributed more uniformly inside the housing 200 when the electrolyte is injected from the injection port 224, compared to the case where the injection port 224 is provided only in the first region R1 or only in the third region R3.

[0071] As described above, in the secondary battery 10 according to this embodiment, a negative electrode member 520 and a positive electrode member 620 are provided in the first sealing body 510 and the second sealing body 610, which are arranged opposite each other in the longitudinal direction (width direction W). Furthermore, a pressure relief valve 222 is provided on the short side 213 of the housing 200, which is located on one side in the short direction (height direction H) perpendicular to the longitudinal direction. That is, the pressure relief valve 222 is provided on a side of the housing 200 that is different from the side on which the negative electrode member 520 and the positive electrode member 620 are provided. Therefore, as described above, when gas and electrolyte are ejected from the pressure relief valve 222, it is possible to suppress the adhesion of the ejected material to the electrode terminals such as the negative electrode member 520 and the positive electrode member 620, and to suppress the unintentional electrical connection of the electrode terminals and metal members etc. arranged around them. As a result, the influence of ejected material from the pressure relief valve on the electrode terminals can be suppressed.

[0072] By providing a single pressure relief valve 222 on the short side 213, the direction in which the ejected material is ejected from the pressure relief valve 222 can be specified to a suitable direction. Furthermore, when multiple secondary batteries 10 are arranged in a row to form an energy storage module, providing a single pressure relief valve 222 to each secondary battery 10 prevents the exhaust path for exhausting the gas discharged from the pressure relief valve from becoming larger compared to a configuration in which multiple pressure relief valves are provided to each secondary battery.

[0073] In addition, since the negative electrode member 520 and positive electrode member 620 are provided on the first sealing body 510 and the second sealing body 610, respectively, the profile can be reduced compared to a configuration in which the negative electrode member 520 and positive electrode member 620 are provided on the short side surface 213.

[0074] (Embodiment 2) Figure 6 is a top view of the secondary battery according to Embodiment 2. The secondary battery 10A according to Embodiment 2 will be described with reference to Figure 6.

[0075] As shown in Figure 6, the secondary battery 10A according to Embodiment 2 differs from the secondary battery 10 according to Embodiment 1 in that it has a different arrangement of the pressure relief valve 222 and multiple liquid injection ports 224A and 224B. The other configurations are almost the same.

[0076] The pressure relief valve 222 is located in the center of one of the short sides 213 in the width direction W. Manufacturing tolerances, such as tolerances, should be taken into account in this center portion.

[0077] The liquid injection port 224A is provided in the first region R1. The liquid injection port 224A is provided on one side of the short side surface 213 in the width direction W. Specifically, the liquid injection port 224A is provided in a position that overlaps with the negative electrode current collector 110N in the height direction H.

[0078] The liquid injection port 224B is provided in the third region R3. The liquid injection port 224B is provided on the other side in the width direction W of one short side surface 213. Specifically, the liquid injection port 224B is provided in a position that overlaps with the positive electrode current collector 110P in the height direction H.

[0079] Even when configured as described above, the secondary battery 10A according to Embodiment 2 can obtain substantially the same effects as the secondary battery 10 according to Embodiment 1.

[0080] In addition, by providing multiple injection ports 224A and 224B on one of the shorter sides 213, the electrolyte can be poured into the housing 200 from multiple locations. This improves the rate at which the electrolyte is injected.

[0081] Furthermore, the electrolyte injection ports 224A and 224B are positioned to overlap the negative electrode current collector 110N and the positive electrode current collector 110P in the height direction H, respectively. The negative electrode current collector 110N is the portion of the electrode body 100 where the negative electrode tabs 122n are gathered, and the positive electrode current collector 110P is the portion of the electrode body 100 where the positive electrode tabs 112p are gathered. As a result, the density of the negative electrode current collector 110N and the positive electrode current collector 110P is lower than that of the portion of the electrode body 100 where the positive electrode 110 and the negative electrode 120 are stacked, and a considerable gap exists between the negative electrode current collector 110N and the positive electrode current collector 110P and the housing 200. Therefore, when the electrolyte is injected from the electrolyte injection ports 224A and 224B, leakage of the electrolyte to the housing 200 can be suppressed.

[0082] Furthermore, since the pressure relief valve 222 is positioned approximately midway between the positive electrode member 620 and the negative electrode member 520, the amount of material ejected from the pressure relief valve 222 adhering to the positive electrode member 620 and the negative electrode member 520 can be further reduced.

[0083] (Embodiment 3) Figure 7 is a perspective view of the battery module according to Embodiment 3. The battery module 1 according to Embodiment 3 will be described with reference to Figure 7.

[0084] As shown in Figure 7, the battery module 1 according to Embodiment 3 is configured by arranging multiple secondary batteries 10 according to Embodiment 1 in a row. The battery module 1 comprises multiple secondary batteries 10, a band 20, multiple busbars 30, and an exhaust path forming member 70.

[0085] Multiple secondary batteries 10 are arranged side by side in the thickness direction T. Spacers may be placed between adjacent secondary batteries 10 in the thickness direction T. Multiple secondary batteries 10 are arranged such that on one side and the other side in the width direction W, the positive electrode members 620 and negative electrode members 520 are arranged alternately in the thickness direction T. Multiple secondary batteries 10 are arranged such that each pressure relief valve 222 is arranged in a substantially straight line in the thickness direction T.

[0086] Multiple busbars 30 are made of a metal such as aluminum or an aluminum alloy. Multiple busbars 30 connect the positive electrode members 620 (more specifically positive electrode terminal boards 621) and negative electrode members 520 (more specifically negative electrode terminal boards 521) of adjacent secondary batteries 10 so that multiple secondary batteries 10 are connected in series.

[0087] The band 20 is annular in shape and surrounds multiple secondary batteries 10. The band 20 is positioned to be in close contact with multiple busbars 30. The band 20 is positioned to cover and abut against the multiple busbars 30. The band 20 is designed to be expandable and contractible. When the band 20 surrounds multiple secondary batteries 10, it restrains the multiple secondary batteries 10 by its contractile force. The material constituting the band 20 is not particularly limited, but an elastic material such as silicone rubber can be used, for example.

[0088] The exhaust path forming member 70 is provided to cover a plurality of pressure relief valves 222. The exhaust path forming member 70 is composed of cover members. In the portion of the exhaust path forming member 70 located above the plurality of secondary batteries 10, it has a shape that extends linearly in the thickness direction T.

[0089] The battery module 1 according to this embodiment has a configuration in which secondary batteries 10, each equipped with a single pressure relief valve 222, are arranged in a row. Compared to a configuration in which each secondary battery is equipped with multiple pressure relief valves, the configuration of the exhaust path forming member 70 for exhausting the gas discharged from the pressure relief valve can be simplified, and an increase in the size of the exhaust path can be suppressed.

[0090] Furthermore, in this embodiment, the positive electrode member 620 and the negative electrode member 520 of the multiple secondary batteries 10 arranged side by side in the thickness direction T are connected by busbars 30 from the outside in the width direction W on both sides in the width direction W. Therefore, compared to a configuration in which the positive electrode member and the negative electrode member provided on the short side 213 of one side (upper side) in the height direction are connected by busbars from one side in the height direction, the battery module 1 can be made lower in height.

[0091] Furthermore, since the elastic band 20 can be attached to multiple secondary batteries 10 from the height direction H, the workability for restraining multiple secondary batteries 10 can be improved.

[0092] In the battery module 1 according to Embodiment 3, the example given is that the secondary batteries 10 according to Embodiment 1 are arranged side by side, but the example is not limited to this, and secondary batteries 10A according to Embodiment 2 may also be arranged side by side.

[0093] Furthermore, while embodiments 1 to 3 described above illustrate and explain the case where one side in the height direction H is the upper side in the vertical direction, the invention is not limited to this. One side in the height direction H may also be the lower side in the vertical direction. In this case, in embodiment 3, the exhaust path forming member 70 may be arranged below the plurality of secondary batteries 10.

[0094] The embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, and all modifications are made in the sense and scope equivalent to the claims. [Explanation of symbols]

[0095] 1 Battery module, 10, 10A secondary battery, 20 Band, 30 Busbar, 50 First cover assembly, 60 Second cover assembly, 70 Exhaust path forming member, 100 Electrode body, 110 Positive electrode, 110N Negative electrode current collector, 110P Positive electrode current collector, 112 Positive electrode current collector foil, 112p Positive electrode tab, 114 Positive electrode active material layer, 120 Negative electrode, 122 Negative electrode current collector foil, 122n Negative electrode tab, 124 Negative electrode active material layer, 130 Separator, 132a Intervening part, 132b First folded part, 132c Second folded part, 132d Outermost covering part, 132e Termination, 200 Housing, 210 Main body, 211, 212 Long side, 213, 214 Short side, 215 1st opening, 216 2nd opening, 222 Pressure relief valve, 224, 224A, 224B Injection port, 510 1st sealing body, 520 Negative electrode member, 521 Negative electrode terminal plate, 522 Insulating plate, 530 Negative electrode connecting member, 531 Negative electrode side 1st current collector, 532 Negative electrode side 2nd current collector, 532a Holding part, 533 Negative electrode connecting pin, 540 Negative electrode side 1st insulating member, 542 Through hole, 550 Negative electrode side 2nd insulating member, 552 Slit, 560 Insulator, 610 2nd sealing body, 620 Positive electrode member, 621 Positive electrode terminal plate, 622 Terminal block, 630 Positive electrode connecting member, 631 Positive electrode side 1st current collector, 632 Positive electrode side 2nd current collector, 632a Holding part, 633 Positive electrode connecting pin, 640 Positive electrode side first insulating member, 642 Through hole, 650 Positive electrode side second insulating member, 652 Slit, 660 Insulator, R1 First region, R2 Second region, R3 Third region, H Height direction, T Thickness direction, W Width direction.

Claims

1. An electrode body comprising a plurality of positive and negative electrodes arranged alternately in a first direction, and a separator disposed between the positive and negative electrodes, A housing for housing the electrode body, The housing includes a positive terminal and a negative terminal, The electrode body includes a positive electrode current collector located at one end of the longitudinal direction of the housing perpendicular to the first direction, and a negative electrode current collector located at the other end of the longitudinal direction. A positive electrode current collector is positioned on one side in the longitudinal direction and electrically connected to the positive electrode terminal, The system further comprises a negative electrode current collector, which is positioned on the other side in the longitudinal direction and electrically connected to the negative electrode terminal, The positive electrode current collector and the positive electrode current collector are welded together. The negative electrode current collector and the negative electrode current collector section are welded together. The housing has a pair of long sides facing the first direction and a pair of short sides facing the short direction of the housing which is perpendicular to the first direction and the longitudinal direction. The separator includes a first folded portion folded back at one end of the positive electrode and the negative electrode in the short direction, a second folded portion folded back at the other end of the positive electrode and the negative electrode in the short direction, and an outermost covering portion that covers the electrode body outside the first and second folded portions. A single pressure relief valve is provided on one of the pair of short sides. A secondary battery in which each of the multiple positive electrode ends and the multiple negative electrode ends located on the side where the pressure relief valve is located in the shorter direction is covered by the separator.

2. The secondary battery according to claim 1, further comprising an insulating film covering the electrode body.

3. A positive electrode side insulating member, a portion of which is disposed between the positive electrode current collector and the electrode body, The secondary battery according to claim 1 or 2, further comprising a negative electrode side insulating member, a portion of which is disposed between the negative electrode current collector and the electrode body.

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