Secondary batteries
The secondary battery design enhances electrolyte impregnation and reduces leakage and contamination by injecting through short sides perpendicular to the electrode arrangement and using a pressure relief valve and spacer member, addressing inefficiencies in conventional designs.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2023-05-24
- Publication Date
- 2026-05-26
AI Technical Summary
Conventional secondary batteries face challenges in efficiently impregnating electrolytic solution due to the design of the liquid injection port and the arrangement of the electrode body, which affects the impregnation property and increases the risk of electrolyte leakage and electrode terminal contamination.
A secondary battery design with a housing configuration that includes a cylindrical main body with openings on both sides, allowing electrolyte injection through short sides perpendicular to the electrode arrangement, multiple injection ports, and a pressure relief valve on a short side, along with a spacer member to prevent leakage and contamination.
Improves electrolyte impregnation efficiency, reduces leakage, and minimizes contamination of electrode terminals, while simplifying the gas exhaust system in battery modules.
Smart Images
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Abstract
Description
Technical Field
[0001] The present disclosure relates to secondary batteries, and particularly to secondary batteries mounted in vehicles.
Background Art
[0002] As a conventional secondary battery, Japanese Patent Application Laid-Open No. 2017-147064 (Patent Document 1) discloses a structure in which an opening of a battery case that opens upward is closed with a lid member, and a liquid injection port is provided on a side surface of the battery case.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In recent years, in secondary batteries, higher capacity has been demanded, and the ratio of the electrode body occupying the inside of the housing has been increasing. In Patent Document 1, when the electrode body is formed large and the liquid injection port provided on the side surface of the housing faces the side surface of the electrode body, it becomes difficult to inject the electrolytic solution into the housing. Furthermore, in Patent Document 1, the electrode body is composed of a wound electrode body, and the winding axis of the wound electrode body is orthogonal to the penetrating direction of the liquid injection port. Therefore, there is a concern that the impregnation property of the electrolytic solution into the electrode body also decreases.
[0005] With the increase in capacity, it is conceivable to configure the housing in a longitudinal shape and accommodate the electrode body in the longitudinally shaped housing. In such a case, it is conceivable to close a pair of openings with a pair of sealing bodies so that both sides in the longitudinal direction are open. In such a configuration, when a liquid injection port is provided in each sealing body and the electrolytic solution is injected from the liquid injection port along the longitudinal direction, the distance that the electrolytic solution travels through the electrode body becomes long, which takes time for liquid injection and the impregnation property of the electrolytic solution into the electrode body decreases.
[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 capable of improving the impregnation of the electrolyte. [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. An injection port is provided on one of the pair of short sides mentioned above.
[0008] According to the above configuration, the electrolyte can be injected into the housing from an injection port provided on one of the short sides in the direction of the short side, thereby shortening the distance the electrolyte travels along the electrode body. In addition, since the positive and negative electrodes are arranged in a first direction perpendicular to the short side, the electrolyte can easily impregnate the electrode body. This improves the impregnation of the electrolyte.
[0009] In the secondary battery based on the above disclosure, a plurality of liquid injection ports may be provided on one of the short sides.
[0010] With the above configuration, the electrolyte can be injected from different points, making it easier for the electrolyte to penetrate the electrode body.
[0011] In the secondary battery based on the above disclosure, the plurality of liquid injection ports may include a first liquid injection port and a second liquid injection port. In this case, when viewed from the short side, the first liquid injection port may be arranged so that at least a portion of it overlaps with the negative electrode current collector. The second liquid injection port may be arranged so that at least a portion of it overlaps with the positive electrode current collector.
[0012] According to the above configuration, the negative electrode current collector and the positive electrode current collector have a lower density compared to the portion of the electrode body where the positive and negative electrodes are stacked, and a considerable gap exists between the negative electrode current collector and the positive electrode current collector and the housing. Therefore, when injecting electrolyte from the first and second injection ports, leakage of electrolyte outside the housing can be suppressed.
[0013] The secondary battery according to the present disclosure may further include a spacer member disposed between the electrode body and one of the short sides. The spacer member may be provided with a storage portion capable of storing an electrolyte.
[0014] With the above configuration, vibration of the electrode body can be suppressed by the spacer member. Furthermore, when injecting the electrolyte, the electrolyte can be stored in the reservoir provided in the spacer member, thus preventing the electrolyte from leaking outside the housing.
[0015] In the secondary battery based on the above disclosure, a single pressure relief valve may be provided on one of the shorter sides.
[0016] 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.
[0017] 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.
[0018] 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.
[0019] 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.
[0020] 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.
[0021] In the secondary battery based on the above disclosure, the liquid injection port may be provided with a vent membrane that allows gas to pass through but not liquid.
[0022] According to the above configuration, when the outside of the housing is made negative pressure and the gas generated during charging is discharged to the outside of the housing, the gas can be discharged using the liquid injection port. Thus, the trouble of separately providing a gas vent can be saved. In addition, the electrolytic solution can be prevented from leaking to the outside of the housing by the ventilation film.
Effects of the Invention
[0023] According to the present disclosure, it is possible to provide a secondary battery capable of improving the impregnation property of the electrolytic solution.
Brief Description of the Drawings
[0024] [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 taken along line III-III shown in FIG. 1. [Figure 4] It is a cross-sectional view taken along 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 cross-sectional view of the secondary battery according to Embodiment 3. [Figure 8] It is a perspective view of the battery module according to Embodiment 4.
Modes for Carrying Out the Invention
[0025] 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 parts are denoted by the same reference numerals in the drawings, and the description thereof will not be repeated.
[0026] (Embodiment 1) Figure 1 is a perspective view of a secondary battery according to Embodiment 1. Figure 2 is an exploded perspective view of a secondary battery according to Embodiment 1. Figure 3 is a cross-sectional view along the line III-III shown in Figure 1.
[0027] As shown in Figures 1 to 3, the secondary battery 10 according to Embodiment 1 comprises an electrode body 100, a housing 200, a positive electrode member 620 as a positive electrode terminal, and a negative electrode member 520 as a negative electrode terminal.
[0028] The housing 200 has a rectangular parallelepiped shape in which the 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 the first direction in which the positive electrode 110 (see Figure 4) and negative electrode 120 (see Figure 4), described later, are arranged side by side. The width direction W is perpendicular to the thickness direction T, and the height direction H is perpendicular to both the thickness direction T and the height direction H. The width of the housing 200 in the width direction W is greater than the height of the housing 200 in the height direction H, with the width direction W being the longitudinal direction of the housing 200 and the height direction H being the short direction of the housing 200.
[0029] The housing 200 houses the electrode body 100 and the electrolyte (not shown) inside. The housing 200 includes a main body 210, a first sealing body 510, and a second sealing body 610.
[0030] The main body 210 has a cylindrical shape with a first opening 215 and a second opening 216 on both sides in the width direction W. More specifically, the main body 210 has a rectangular cylindrical shape with openings on 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.
[0031] 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.
[0032] 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.
[0033] 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. . Seal The sealing member 225 is a member that seals the injection port 224 after the electrolyte is 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.
[0034] 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. 。
[0035] 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.
[0036] 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.
[0037] 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. The second sealing body 610 is provided with a positive electrode member 620.
[0038] 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.
[0039] 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.
[0040] 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.
[0041] 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.
[0042] 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.
[0043] 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.
[0044] 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.
[0045] The negative electrode side second current collector 532 is made of a thin plate-shaped conductive material. 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.
[0046] 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.
[0047] 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.
[0048] 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.
[0049] 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.
[0050] 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).
[0051] 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.
[0052] 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.
[0053] 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.
[0054] 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.
[0055] The positive electrode side first current collector 531 is made of a thin plate-shaped conductive material. The positive electrode side first current collector 531 is connected to the positive electrode current collector section 110P by laser welding or ultrasonic welding.
[0056] 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.
[0057] 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.
[0058] 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.
[0059] 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.
[0060] The positive electrode side first insulating member 540 and the positive electrode side second insulating member 550 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 latter being inserted through the slit 552.
[0061] 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).
[0062] 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.
[0063] 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.
[0064] 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.
[0065] 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.
[0066] 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.
[0067] 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.
[0068] 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.
[0069] 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.
[0070] 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.
[0071] 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.
[0072] 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.
[0073] 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).
[0074] 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.
[0075] 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.
[0076] 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.
[0077] 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.
[0078] 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.
[0079] In the secondary battery 10 according to this embodiment, the electrolyte can be injected into the housing 200 in the short direction from the injection port 224 provided on one short side 213, thereby shortening the distance the electrolyte travels along the electrode body. In addition, since the positive electrode 110 and the negative electrode 120 are arranged side by side in a first direction perpendicular to the short direction, the electrolyte can easily impregnate the electrode body 100 from the end side of the positive electrode 110 and the negative electrode 120 located on one side in the short direction. This improves the impregnation of the electrolyte.
[0080] Furthermore, 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). In addition, 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, if 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.
[0081] 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.
[0082] 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.
[0083] (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.
[0084] As shown in Figure 6, the secondary battery 10A according to Embodiment 2 differs from the secondary battery 10 according to Embodiment 1 in the arrangement of the pressure relief valve 222 and the provision of multiple liquid injection ports. The other configurations are substantially the same.
[0085] 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.
[0086] The multiple liquid injection ports include a first liquid injection port 224A and a second liquid injection port 224B. The first liquid injection port 224A is provided in the first region R1. The first liquid injection port 224A is provided on one side of the width direction W on one of the short sides 213. Specifically, at least a portion of the first liquid injection port 224A is arranged to overlap with the negative electrode current collector 110N in the height direction H.
[0087] The second liquid injection port 224B is provided in the third region R3. The second liquid injection port 224B is provided on the other side in the width direction W of one short side surface 213. Specifically, the second liquid injection port 224B is positioned such that at least a portion of it overlaps with the positive electrode current collector 110P in the height direction H.
[0088] 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.
[0089] In addition, by providing multiple injection ports (first injection port 224A, second injection port 224B) on one of the short sides 213, the electrolyte can be poured into the housing 200 from multiple locations. This makes it easier for the electrolyte to be impregnated into the electrode body 100.
[0090] Furthermore, at least a portion of the first liquid injection port 224A and the second liquid injection port 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. For this reason, 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 there is a considerable gap between the negative electrode current collector 110N and the positive electrode current collector 110P and the housing 200. Therefore, when injecting electrolyte from the first injection port 224A and the second injection port 224B, leakage of electrolyte to the housing 200 side can be suppressed.
[0091] 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.
[0092] (Embodiment 3) Figure 7 is a cross-sectional view of the secondary battery according to Embodiment 3. Note that Figure 7 is a cross-sectional view corresponding to Figure 3. The secondary battery 10B according to Embodiment 3 will be described with reference to Figure 7.
[0093] As shown in Figure 7, the secondary battery 10B according to Embodiment 3 differs from the secondary battery 10 according to Embodiment 1 in that it is equipped with a spacer member 80. The other configurations are substantially the same.
[0094] The spacer member 80 is positioned between the short side surface 213 and the electrode body 100. The spacer member 80 may be made of an elastic material such as urethane rubber, or it may be made of a resin material. The spacer member 80 functions as a buffer and suppresses vibration of the electrode body 100. The spacer member 80 is sandwiched between the short side surface 213 and the electrode body 100. The spacer member 80 is insulating and insulates the short side surface 213 from the electrode body 100.
[0095] The spacer member 80 is provided with a storage section 81 capable of storing electrolyte. The storage section 81 is provided so as to communicate with the internal space of the housing 200. The storage section 81 is, for example, made up of a weight-reducing section. The storage section 81 may be provided so as to penetrate the spacer member 80 in the height direction H.
[0096] Even when configured as described above, the secondary battery 10B according to Embodiment 3 can obtain substantially the same effects as the secondary battery 10 according to Embodiment 1.
[0097] In addition, the spacer member 80 can suppress vibration of the electrode body 100. Furthermore, when injecting the electrolyte, the electrolyte can be stored in the storage section 81 provided in the spacer member 80, thereby preventing the electrolyte from leaking outside the housing 200.
[0098] (Embodiment 4) Figure 8 is a perspective view of the battery module according to Embodiment 4. The battery module 1 according to Embodiment 4 will be described with reference to Figure 8.
[0099] As shown in Figure 8, 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.
[0100] 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.
[0101] 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.
[0102] 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.
[0103] 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.
[0104] 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.
[0105] Furthermore, in this embodiment, the multiple secondary batteries 10 arranged in line in the thickness direction T are in the width direction W On one side and the other side, the positive electrode member 620 and the negative electrode member 520 are connected by a busbar 30 from the outside 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 a busbar from one side in the height direction, the battery module 1 can be made lower in height.
[0106] 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.
[0107] 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. However, the example is not limited to this, and secondary batteries 10A according to Embodiment 2 or secondary batteries 10B according to Embodiment 3 may also be arranged side by side.
[0108] Furthermore, while embodiments 1 to 4 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 4, the exhaust path forming member 70 may be arranged below the plurality of secondary batteries 10.
[0109] 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 within the meaning and scope equivalent to the claims. [Explanation of Symbols]
[0110] 1 Battery module, 10, 10A, 10B secondary battery, 20 Band, 30 Busbar, 50 First lid assembly, 60 Second lid assembly, 70 Exhaust path forming member, 80 Spacer member, 81 Storage section, 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 section, 132b First folded section, 132c Second folded section, 132d Outermost covering section, 132e Termination, 200 Housing, 210 Main body section, 211, 212 Long side, 213, 214 Short side, 215 First opening, 216 Second opening, 222 Pressure relief valve, 224 Injection port, 224A First injection port, 224B Second injection port, 225 Sealing member, 510 First sealing body, 520 Negative electrode member, 521 Negative electrode terminal plate, 522 Insulating plate, 530 Negative electrode connecting member, 531 Negative electrode side first current collector, 532 Negative electrode side second current collector, 532a Holding part, 533 Negative electrode connecting pin, 540 Negative electrode side first insulating member, 542 Through hole, 550 Negative electrode side second insulating member, 552 Slit, 560 Insulator, 610 Second sealing body, 620 Positive electrode member, 621 Positive electrode terminal plate, 622 Terminal block, 630 Positive electrode connecting member, 631 632 First current collector, 632a Second current collector, 633 Holding part, 633 Positive electrode connecting pin, 640 First insulating member, 642 Through hole, 650 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 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, The housing is provided with a positive terminal and a negative terminal, 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, The positive 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 which is perpendicular to the first direction and the longitudinal direction. The electrode body includes a negative electrode current collector located at one end in the longitudinal direction and electrically connected to the negative electrode terminal, and a positive electrode current collector located at the other end in the longitudinal direction and electrically connected to the positive electrode terminal. One of the pair of short sides is provided with a liquid injection port. The liquid injection port is positioned to overlap at least one of the positive electrode current collector and the negative electrode current collector when viewed from the short side. The positive electrode current collector is such that, in the portion of the electrode body where the positive electrode and the negative electrode are aligned, the distance from the housing in the first direction is greater than that of the positive electrode located furthest out in the first direction. A secondary battery in which the negative electrode current collector is located in a portion of the electrode body where the positive electrode and the negative electrode are aligned, and the distance from the housing in the first direction is greater than that of the negative electrode located furthest out in the first direction.
2. The secondary battery according to claim 1, wherein a plurality of liquid injection ports are provided on one of the short sides.
3. The plurality of injection ports include a first injection port and a second injection port, The secondary battery according to claim 2, wherein, when viewed from the short-side direction, the first liquid injection port is arranged such that at least a portion of it overlaps with the negative electrode current collector, and the second liquid injection port is arranged such that at least a portion of it overlaps with the positive electrode current collector.
4. The facility further comprises a spacer member disposed between the electrode body and one of the short sides, The secondary battery according to claim 3, wherein the spacer member is provided with a storage portion capable of storing electrolyte.
5. A secondary battery according to any one of claims 1 to 4, wherein a single pressure relief valve is provided on one of the shorter sides.
6. The secondary battery according to claim 5, wherein the pressure relief valve is positioned at a distance in the longitudinal direction from both ends of the one short side, for a distance of at least one-third of the length of the one short side in the longitudinal direction.
7. The secondary battery according to claim 6, wherein the pressure relief valve is provided in the center of one of the short sides in the longitudinal direction.
8. The secondary battery according to any one of claims 1 to 4, wherein the liquid injection port is provided with a permeable membrane that allows gas to pass through but not liquid.