Secondary battery and battery pack

Abstract

The invention provides a secondary battery and a battery pack. This secondary battery is provided with: an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; and an exterior body that accommodates the electrode body and the electrolyte, the exterior body including a first sealing plate and a second sealing plate that are disposed so as to face each other, the first sealing plate including a first exhaust valve that exhausts gas inside the exterior body to the outside of the exterior body when the pressure inside the exterior body is equal to or greater than a predetermined value, and the second sealing plate including a second exhaust valve that exhausts gas inside the exterior body to the outside of the exterior body when the pressure inside the exterior body is equal to or greater than a predetermined value. And a second exhaust valve that exhausts the gas inside the outer housing to the outside of the outer housing when the pressure inside the outer housing is equal to or greater than a predetermined value. The secondary battery (1) has higher reliability.

Description

Technical Field

[0001] The present technology relates to secondary batteries and battery packs. Background Art

[0002] Japanese Patent Gazette No. 4537353 discloses a square secondary battery in which an electrode group (25) is housed in a battery case (14) having openings (14a, 14b) at both ends, and electrode terminals (21, 23) are respectively mounted on covers (33, 33') for sealing the openings (14a, 14b).

[0003] By becoming a square battery with a positive terminal provided on one side of the battery housing and a negative terminal provided on the other end, it is easy to become a battery pack with a low height. However, a secondary battery with higher reliability is required. For example, the exhaust path of the gas generated when an abnormality occurs in the secondary battery (thermal runaway, etc.) is limited. In addition, in recent years, the amount of gas generated in secondary batteries has increased.

[0004] The present technology aims to provide a secondary battery and a battery pack with higher reliability. Summary of the invention

[0005] The present technology provides the following secondary batteries and battery packs.

[0006] [1] A secondary battery, comprising: an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; and an outer casing containing the electrode body and an electrolyte, the outer casing including a first wall and a second wall arranged to face each other, the first wall including a first exhaust valve that discharges gas in the outer casing to the outside of the outer casing when the pressure in the outer casing becomes greater than a specified value, and the second wall including a second exhaust valve that discharges gas in the outer casing to the outside of the outer casing when the pressure in the outer casing becomes greater than a specified value.

[0007] [2] In the secondary battery described in [1], the outer casing includes: a shell body having a first opening at one end thereof and a second opening at the other end thereof; a first sealing plate for sealing the first opening; and a second sealing plate for sealing the second opening, the first wall being the first sealing plate and the second wall being the second sealing plate, the first sealing plate being provided with a first electrode terminal, and the second sealing plate being provided with a second electrode terminal, the electrode body including a first electrode sheet group at one end thereof, the first electrode sheet group being composed of a plurality of first electrode sheets electrically connected to the first electrode, and the electrode body including a second electrode sheet group at the other end thereof, the second electrode sheet group being composed of a plurality of second electrode sheets electrically connected to the second electrode, the first electrode sheet group being electrically connected to the first electrode terminal, and the second electrode sheet group being electrically connected to the second electrode terminal.

[0008] [3] In the secondary battery described in [1] or [2], in the long side direction of the first wall, the first exhaust valve is arranged in a manner deviating from the center of the first wall toward the first direction side, and in the long side direction of the second wall, the second exhaust valve is arranged in a manner deviating from the center of the second wall toward the first direction side.

[0009] [4] In the secondary battery described in [1] or [2], the shape of the first exhaust valve when observed from above has a major axis and a minor axis, and the first exhaust valve is arranged in a direction with the major axis extending along the short side direction of the first wall. In the long side direction of the first wall, the center of the first exhaust valve is arranged at a position deviated from the center of the first wall.

[0010] [5] A battery pack comprising a plurality of secondary batteries as described in any one of [1] to [4], wherein in the battery pack, the secondary batteries are arranged in a manner such that the long side directions of the first wall and the long side directions of the second wall extend in the vertical direction, a first exhaust valve is arranged at a position higher than the center of the vertical direction of the first wall in the long side direction of the first wall, and a second exhaust valve is arranged at a position higher than the center of the vertical direction of the second wall in the long side direction of the second wall.

[0011] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a front view of a secondary battery.

[0013] Figure 2 It means observing from the direction of arrow II Figure 1 A diagram showing the state of a secondary battery.

[0014] Figure 3 It means observing from the direction of arrow III Figure 1 A diagram showing the state of a secondary battery.

[0015] Figure 4 It means observing from the direction of arrow IV Figure 1 A diagram showing the state of a secondary battery.

[0016] Figure 5 yes Figure 1 A front cross-sectional view of a secondary battery is shown.

[0017] Figure 6 It is a diagram showing another embodiment of the first exhaust valve.

[0018] Figure 7 It is a front view showing a negative electrode original plate before forming a negative electrode plate.

[0019] Figure 8 yes Figure 7 The VIII-VIII cross-sectional view of the negative electrode original plate shown.

[0020] Fig. 9 It is a front view showing a negative electrode plate formed from a negative electrode original plate.

[0021] Fig.10 It is a front view showing a positive electrode original plate before forming a positive electrode plate.

[0022] Fig.11 yes Fig.10 XI-XI cross-sectional view of the positive electrode original plate shown.

[0023] Fig.12 It is a front view showing a positive electrode plate formed from a positive electrode original plate.

[0024] Fig.13 It is a diagram showing an electrode body and a current collector taken out from a secondary battery.

[0025] Fig.14 It is a diagram showing the connection structure between the negative electrode sheet group and the negative electrode current collector.

[0026] Fig.15 yes Fig.14 Front view of the connection structure shown.

[0027] Fig.16 yes Fig.14 A cross-sectional view of the connection structure shown.

[0028] Fig.17 It is a diagram showing the step of inserting the electrode body into the case body.

[0029] Fig.18 This is a diagram showing a step of providing a separator between a sealing plate and an electrode body.

[0030] Fig.19 It is a cross-sectional view showing a state where a separator is provided between a sealing plate and an electrode body.

[0031] Fig. 20 It is a diagram showing a modified example of the spacer.

[0032] Fig.21 This is a diagram showing an example of a mechanism for pressing the electrode body via a sealing plate and a separator.

[0033] Fig. 22 It means viewing from the Z axis direction Fig.21 A diagram showing the state of the mechanism.

[0034] Fig.23 This is a three-dimensional diagram of another type of spacer.

[0035] Fig.24 This is a three-dimensional diagram of another type of spacer.

[0036] Fig.25 This is a three-dimensional diagram of another type of spacer.

[0037] Fig.26 It is a flowchart showing each process of the manufacturing method of a secondary battery.

[0038] Fig. 27 is a schematic diagram showing the appearance of a battery pack.

[0039] Fig.28 and Figure 3 , which corresponds to the figure, is a figure showing another embodiment of the first sealing plate.

[0040] Fig.29 and Figure 4 , which corresponds to the figure, is a figure showing another embodiment of the second sealing plate. DETAILED DESCRIPTION

[0041] Hereinafter, embodiments of the present technology will be described. In addition, the same reference numerals are given to the same or corresponding parts, and the description thereof may not be repeated.

[0042] In addition, in the embodiments described below, when the number, amount, etc. are mentioned, the scope of the present technology is not necessarily limited to the number, amount, etc., unless otherwise specified. In addition, in the following embodiments, except for the cases where there are special records, each component is not necessarily essential to the present technology. In addition, the present technology is not necessarily limited to the technology that has all the effects mentioned in the present embodiment.

[0043] In addition, in this specification, the descriptions of "comprise", "include", and "have" are open forms. That is, when a certain structure is included, other structures other than the structure may or may not be included.

[0044] In addition, in this specification, when geometrical terms and terms indicating position and direction relationships are used, such as "parallel", "orthogonal", "oblique 45 degrees", "coaxial", "along", etc., these terms allow for manufacturing errors or some changes. In this specification, when terms such as "upper side" and "lower side" are used to indicate relative positional relationships, these terms are used to indicate relative positional relationships in one state, and the relative positional relationship can be reversed or rotated to any angle depending on the installation direction of each mechanism (for example, turning the entire mechanism upside down, etc.).

[0045] In this specification, "battery" is not limited to lithium-ion batteries, and may include other batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this specification, "electrode" may be collectively referred to as positive electrode and negative electrode. In addition, "electrode plate" may be collectively referred to as positive electrode plate and negative electrode plate.

[0046] (Overall structure of the battery)

[0047] Figure 1 It is a front view of the secondary battery 1 according to the present embodiment. Figure 2 to Figure 4 They are respectively viewed from the direction of arrow II, arrow III, and arrow IV. Figure 1 The diagram shows the state of the secondary battery 1. Figure 5 yes Figure 1 The secondary battery 1 is shown in front cross-sectional view. Fig.28 and Figure 3 , which corresponds to the figure showing another embodiment of the first sealing plate, Fig.29 and Figure 4 , which corresponds to the figure, is a figure showing another embodiment of the second sealing plate.

[0048] The secondary battery 1 can be mounted on an electric vehicle (BEV), a plug-in hybrid electric vehicle (PHEV), a hybrid electric vehicle (HEV), etc. However, the use of the secondary battery 1 is not limited to vehicle-mounted use.

[0049] like Figure 1 to Figure 5As shown, the secondary battery 1 includes an outer casing 100, an electrode body 200, and a current collector 300. The outer casing 100 includes a case body 110, a first sealing plate 121 as a first wall, and a second sealing plate 122 as a second wall.

[0050] In this application specification, there is Figure 1 to Figure 5 The X-axis direction (first direction) shown is called the "width direction" of the secondary battery 1 or the shell body 110. Similarly, the Y-axis direction (second direction) is called the "thickness direction" of the secondary battery 1 or the shell body 110. Similarly, the Z-axis direction (third direction) is called the "height direction" of the secondary battery 1 or the shell body 110. In addition, in the description of this disclosure, the Z-axis direction is consistent with the direction of the sky and the earth. Therefore, in Figure 1 In the secondary battery 1 shown in the figure, the upper side in the figure is vertically upward, and the lower side in the figure is vertically downward. Figure 2 Indicates the state viewed from the bottom.

[0051] When forming a battery pack including secondary batteries 1, a plurality of secondary batteries 1 are stacked in their thickness direction. The stacked secondary batteries 1 may be constrained in the stacking direction (Y-axis direction) by a constraining member to form a battery module, or the battery pack may be directly supported on the side of the battery pack housing without using a constraining member.

[0052] The case body 110 is formed of a cylindrical, preferably rectangular, member. This provides a rectangular secondary battery 1. The case body 110 is made of metal. Specifically, the case body 110 is made of aluminum, aluminum alloy, iron, or iron alloy.

[0053] like Figure 1 , Figure 2 As shown in FIG. 1 , a first sealing plate 121 and a second sealing plate 122 are provided at both ends of the housing body. The housing body 110 is formed by, for example, bringing the ends of the plate-like members subjected to bending into contact with each other (at Figure 2 The square tube shape can be formed by joining the joint portion 110A shown in the example in FIG. 1 (e.g., laser welding) to each other. The corner of the "square tube shape" may also have an R shape.

[0054] In this embodiment, the length of the shell body 110 in the width direction (X-axis direction) of the secondary battery 1, that is, in the direction connecting the first sealing plate 121 serving as the first wall and the second sealing plate 122 serving as the second wall (X-axis direction), is formed to be longer than the length in the thickness direction (Y-axis direction) and the height direction (Z-axis direction) of the secondary battery 1.

[0055] The dimension (width) of the shell body 110 in the X-axis direction is preferably 30 cm or more. Thus, a relatively large (high capacity) secondary battery 1 can be formed. The dimension (height) of the shell body 110 in the Z-axis direction is preferably 20 cm or less, more preferably 15 cm or less, and further preferably 10 cm or less. Thus, a secondary battery 1 with a relatively low height (low height) can be formed, for example, the mountability on a vehicle is improved.

[0056] like Figure 3 As shown, a first opening 111 is provided at an end of one side of the shell body 110. The first opening 111 is sealed by a first sealing plate 121. A negative terminal 131 (first electrode terminal), a first liquid injection port 141 and a first exhaust valve 151 are provided on the first sealing plate 121. The positions of the negative terminal 131 and the first exhaust valve 151 can be changed appropriately. The first opening 111 and the first sealing plate 121 have a roughly rectangular shape with the Y-axis direction being the short side direction and the Z-axis direction being the long side direction. In the present embodiment, the first exhaust valve 151 is arranged to deviate from the center CL of the first sealing plate 121 in the long side direction (Z direction) of the first sealing plate 121 toward the first direction (upward in the vertical direction). In addition, as Fig.28 As shown, the first liquid injection port 141 may be provided on the opposite side of the first exhaust valve 151 with respect to the negative electrode terminal 131 in the longitudinal direction (Z direction) of the first sealing plate 121 .

[0057] like Figure 4 As shown, a second opening 112 is provided at the other end of the shell body 110. The second opening 112 is sealed by a second sealing plate 122. A positive terminal 132 (second electrode terminal), a second liquid injection port 142 and a second exhaust valve 152 are provided on the second sealing plate 122. The positions of the positive terminal 132 and the second exhaust valve 152 can be changed appropriately. The second opening 112 and the second sealing plate 122 have a roughly rectangular shape with the Y-axis direction being the short side direction and the Z-axis direction being the long side direction. The second exhaust valve 152 is arranged to deviate from the center CL of the second sealing plate 122 in the long side direction (Z direction) of the second sealing plate 122 toward the first direction (upward in the vertical direction). In addition, as Fig.29 As shown, the second liquid injection port 142 may be provided on the side opposite to the second exhaust valve 152 with respect to the positive electrode terminal 132 in the longitudinal direction (Z direction) of the second sealing plate 122 .

[0058] By providing the first exhaust valve 151 and the second exhaust valve 152 on the opposing sealing plates, in the electrode body 200 described later, when an abnormality such as a short circuit occurs on one end side, when the exhaust valve is only located on the other side, the gas discharge from the outer body 100 to the outside may be delayed. On the other hand, by providing the exhaust valves on the first sealing plate 121 and the second sealing plate 122, respectively, the delay in gas discharge can be suppressed even if an abnormality occurs at either end of the electrode body 200. This is particularly effective in a secondary battery having a long length (X direction) in the direction connecting the first sealing plate 121 and the second sealing plate 122.

[0059] In making Figure 3 When the upper part in the figure is vertically above, it is preferred to arrange the first exhaust valve 151 at a position away from the center (center CL) of the first sealing plate 121 or at a position above the center (a position as far away from the center as possible). This is because in the event of an abnormality, the excess solvent such as the electrolyte can be slightly ejected from the first exhaust valve 151. In addition, by arranging it at a position as far away from the center as possible, the stress caused by the deformation (central expansion) of the first sealing plate 121 during normal use can be reduced.

[0060] As the first exhaust valve 151, a runway-shaped exhaust valve is used. The long side direction of the runway shape is arranged along the short side direction of the first sealing plate 121, and the short side direction of the runway shape is arranged along the long side direction of the first sealing plate 121. By adopting this configuration, even if the outer body 100 is deformed during normal use, the load on the first exhaust valve 151 can be reduced (to suppress malfunction, changes in differential pressure, etc.) and the opening area can be ensured. In addition, the efficiency of the gas discharge opening area when the first exhaust valve 151 functions relative to the first sealing plate 121 can be improved.

[0061] The first exhaust valve 151 is provided with a first rupture groove 151A having a track shape that is thinner than the plate thickness of the first sealing plate 121, and a first auxiliary rupture groove 151B extending vertically is provided in the center. A first fragile portion 151C having a linear shape that is thinner than the thickness of the first auxiliary rupture groove 151B is further provided. When the internal pressure of the outer body 100 becomes equal to or greater than a predetermined value, the first exhaust valve 151 is judged based on the first fragile portion 151C, and the first exhaust valve 151 is peeled off from the first sealing plate 121 along the first rupture groove 151A and the first auxiliary rupture groove 151B, thereby discharging the gas in the outer body 100 to the outside of the outer body 100. The first fragile portion 151C is not limited to a straight line, and may also be in a track shape along the inner side of the first rupture groove 151A.

[0062] The second exhaust valve 152 is provided with a second rupture groove 152A in a racetrack shape that is thinner than the plate thickness of the second sealing plate 122, and a second auxiliary rupture groove 152B extending vertically is provided in the center. A second fragile portion 152C in a straight line shape that is thinner than the thickness of the second auxiliary rupture groove 152B is further provided. When the internal pressure of the outer body 100 becomes equal to or greater than a predetermined value, the second exhaust valve 152 is judged based on the second fragile portion 152C, and the second exhaust valve 152 is peeled off from the second sealing plate 122 along the second rupture groove 152A and the second auxiliary rupture groove 152B, thereby discharging the gas in the outer body 100 to the outside of the outer body 100. The second fragile portion 152C is not limited to a straight line, and may also be in a racetrack shape along the inner side of the second rupture groove 152A.

[0063] The first exhaust valve 151 and the second exhaust valve 152 are of the same shape and are disposed at the same opposing position, but may have different shapes, formation positions, valve opening pressures, etc. For example, in the case of thermal runaway of a secondary battery, it is effective to discharge the internal combustion of the thermally runaway secondary battery outside the outer casing in order to prevent the secondary battery from burning adjacent secondary batteries in the same battery pack. In order to discharge the internal combustion outside the outer casing, it is preferred that the flow rate of the gas exhaust at the opening of the exhaust valve is high, which is equivalent to a smaller opening area.

[0064] However, if the opening area of ​​the exhaust valve is small, the exhaust valve opening may be clogged by the debris of the internally burned electrode body, and the exhaust may stagnate. Therefore, for example, by designing the opening area of ​​the second exhaust valve 152 to be greater than the opening area of ​​the first exhaust valve 151, it is possible to select that the discharge (flow rate) of the internal combustion matter in the first exhaust valve 151 with a small opening area is prioritized, and the exhaust (flow rate) is prioritized in the second exhaust valve 152 with a large opening area. In addition, the ratio of the opening area of ​​the second exhaust valve 152 / the opening area of ​​the first exhaust valve 151 can be about 1.1.

[0065] In addition, if Figure 6 As shown, the first exhaust valve 151 may be circular in shape. Specifically, the first rupture groove 151A may be circular, and a circular first fragile portion 151C may be provided along the inner side of the first rupture groove 151A. The same may be applied to the second exhaust valve 152.

[0066] The first sealing plate 121 and the second sealing plate 122 are made of metal. Specifically, the first sealing plate 121 and the second sealing plate 122 are made of aluminum, aluminum alloy, iron, iron alloy, or the like.

[0067] The negative electrode terminal 131 is electrically connected to the negative electrode of the electrode body 200 . The positive electrode terminal 132 is electrically connected to the positive electrode of the electrode body 200 .

[0068] The negative electrode terminal 131 is made of a conductive material (more specifically, a metal), for example, copper or a copper alloy, etc. A portion or layer made of aluminum or an aluminum alloy may be provided on the outer surface of the negative electrode terminal 131 .

[0069] The positive electrode terminal 132 is made of a conductive material (more specifically, a metal), and can be made of, for example, aluminum or an aluminum alloy.

[0070] The electrode body 200 is a flat electrode body having a positive electrode plate and a negative electrode plate described later. Specifically, the electrode body 200 is a wound electrode body formed by winding a strip-shaped positive electrode plate and a strip-shaped negative electrode plate together via a strip-shaped separator not shown. However, in this specification, the "electrode body" is not limited to a wound electrode body, and may also be a stacked electrode body formed by alternately stacking a plurality of positive plates and a plurality of negative plates. The electrode body includes a plurality of positive plates and a plurality of negative plates, and the positive electrode sheets provided on each positive plate may also be stacked to form a positive electrode sheet group, and the negative electrode sheets provided on each negative plate may also be stacked to form a negative electrode sheet group.

[0071] Refer again Figure 5 The outer casing 100 accommodates the electrode body 200. The electrode body 200 is accommodated in the outer casing 100 so that its winding axis is parallel to the X-axis direction.

[0072] Specifically, a single or a plurality of wound electrode bodies and an electrolyte (electrolyte) not shown are contained inside an insulating sheet 600 as a separator described later and arranged in the outer casing 100. As the electrolyte (non-aqueous electrolyte), for example, an electrolyte obtained by dissolving LiPF6 at a concentration of 1.2 mol / L in a non-aqueous solvent obtained by mixing ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) in a volume ratio (25° C.) of 30:30:40 can be used. In addition, a solid electrolyte can also be used instead of the electrolyte.

[0073] The electrode body 200 includes a negative electrode sheet group 210A (first electrode sheet group) provided at an end (first end) on the first sealing plate 121 side, and a positive electrode sheet group 220A (second electrode sheet group) provided at an end (second end) on the second sealing plate 122 side. The negative electrode sheet group 210A and the positive electrode sheet group 220A are connected to the negative electrode and the positive electrode of the electrode body 200, respectively. The negative electrode sheet group 210A and the positive electrode sheet group 220A are formed to protrude from the main body portion (the portion where the positive electrode plate and the negative electrode plate are stacked via the separator) of the electrode body 200 toward the first sealing plate 121 and the second sealing plate 122.

[0074] The current collector 300 includes a negative electrode current collector 310 (first current collector) and a positive electrode current collector 320 (second current collector). The negative electrode current collector 310 and the positive electrode current collector 320 are each formed of a plate-like member. The electrode body 200 is electrically connected to the negative electrode terminal 131 and the positive electrode terminal 132 via the current collector 300 .

[0075] The negative electrode current collector 310 is disposed on the first sealing plate 121 via a resin insulating member. The negative electrode current collector 310 is electrically connected to the negative electrode sheet group 210A and the negative electrode terminal 131. The negative electrode current collector 310 is made of a conductive material (more specifically, metal), such as copper or a copper alloy.

[0076] The positive electrode collector 320 is arranged on the second sealing plate 122 via an insulating member made of resin. The positive electrode collector 320 is electrically connected to the positive electrode sheet group 220A and the positive terminal 132. The positive electrode collector 320 is composed of a conductive material (more specifically, a metal), for example, aluminum or an aluminum alloy. In addition, the positive electrode sheet group 220A can also be electrically connected to the second sealing plate 122 directly or via the positive electrode collector 320. In this case, the second sealing plate 122 can also serve as the positive terminal 123.

[0077] (Structure of Electrode Body 200)

[0078] Figure 7 2 is a front view showing a negative electrode original plate 210S before forming a negative electrode plate 210 (first electrode). Figure 8 yes Figure 7 The VIII-VIII cross-sectional view of the negative electrode original plate 210S shown in FIG. Fig. 9 1 is a front view showing a negative electrode plate 210 formed from a negative electrode original plate 210S.

[0079] The negative electrode plate 210 is manufactured by processing the negative electrode original plate 210S. Figure 6 and Figure 7 As shown, the negative electrode original plate 210S includes a negative electrode core 211 and a negative electrode active material layer 212. The negative electrode core 211 is a copper foil or a copper alloy foil.

[0080] The negative electrode core 211 has a negative electrode active material layer 212 formed thereon except for one end portion of both surfaces. The negative electrode active material layer 212 is formed by applying a negative electrode active material layer slurry using a die coater.

[0081] The negative electrode active material layer slurry is prepared by kneading graphite as a negative electrode active material, styrene butadiene rubber (SBR) and carboxymethyl cellulose (CMC) as binders, and water as a dispersion medium so that the mass ratio of graphite:SBR:CMC is about 98:1:1.

[0082] The negative electrode core 211 coated with the negative electrode active material layer slurry is dried to remove the water contained in the negative electrode active material layer slurry, thereby forming the negative electrode active material layer 212. Furthermore, the negative electrode original plate 210S including the negative electrode core 211 and the negative electrode active material layer 212 is formed by compressing the negative electrode active material layer 212. The negative electrode original plate 210S is cut into a predetermined shape to form the negative electrode plate 210. The negative electrode original plate 210S can be cut by laser processing based on energy line irradiation, metal mold processing, or tool processing.

[0083] like Fig. 9 As shown, at one end in the width direction of the negative electrode plate 210 formed by the negative electrode original plate 210S, a plurality of negative electrode sheets 210B formed by the negative electrode core 211 are provided. When the negative electrode plate 210 is wound, the plurality of negative electrode sheets 210B are stacked to form a negative electrode sheet group 210A. The positions of the plurality of negative electrode sheets 210B and the lengths of the protruding directions are appropriately adjusted in consideration of the state in which the negative electrode sheet group 210A is connected to the negative electrode collector 310. In addition, the shape of the negative electrode sheet 210B is not limited to Fig. 9 The shape illustrated in .

[0084] Fig.10 2 is a front view showing a positive electrode original plate 220S before forming a positive electrode plate 220 (second electrode). Fig.11 yes Fig.10 The XI-XI cross-sectional view of the positive electrode original plate 220S shown in FIG. Fig.12 1 is a front view showing a positive electrode plate 220 formed of a positive electrode original plate 220S.

[0085] The positive electrode plate 220 is manufactured by processing the positive electrode original plate 220S. Fig.10 and Fig.11 As shown, the positive electrode original plate 220S includes a positive electrode core 221, a positive electrode active material layer 222, and a positive electrode protective layer 223. The positive electrode core 221 is an aluminum foil or an aluminum alloy foil.

[0086] The positive electrode core body 221 has a positive electrode active material layer 222 formed thereon except for one end portion of both surfaces. The positive electrode active material layer 222 is formed on the positive electrode core body 221 by applying a positive electrode active material layer slurry using a die coater.

[0087] The positive electrode active material layer slurry is prepared by kneading lithium nickel cobalt manganese composite oxide as a positive electrode active material, polyvinylidene fluoride (PVdF) as a binding material, a carbon material as a conductive material, and N-methyl-2-pyrrolidone (NMP) as a dispersion medium in such a manner that the mass ratio of lithium nickel cobalt manganese composite oxide:PVdF:carbon material becomes approximately 97.5:1:1.5.

[0088] The positive electrode protection layer 223 is in contact with the positive electrode core 221 and is formed at one end of the positive electrode active material layer 222 in the width direction. The positive electrode protection layer 223 is formed on the positive electrode core 221 by applying the positive electrode protection layer slurry using a die coater. The positive electrode protection layer 223 has a resistance greater than that of the positive electrode active material layer 222.

[0089] The positive electrode protective layer slurry was prepared by kneading alumina powder, a carbon material as a conductive material, PVdF as a binder, and NMP as a dispersion medium so that the mass ratio of alumina powder:carbon material:PVdF was about 83:3:14.

[0090] The positive electrode core 221 coated with the positive electrode active material layer slurry and the positive electrode protective layer slurry is dried and the NMP contained in the positive electrode active material layer slurry and the positive electrode protective layer slurry is removed to form the positive electrode active material layer 222 and the positive electrode protective layer 223. Furthermore, the positive electrode original plate 220S including the positive electrode core 221, the positive electrode active material layer 222 and the positive electrode protective layer 223 is formed by compressing the positive electrode active material layer 222. The positive electrode plate 220 is formed by cutting the positive electrode original plate 220S into a predetermined shape. The positive electrode original plate 220S can be cut by laser processing based on energy line irradiation, metal mold processing, or tool processing.

[0091] like Fig.12 As shown, at one end in the width direction of the positive plate 220 formed by the positive original plate 220S, a plurality of positive electrode sheets 220B formed by the positive electrode core 221 are provided. When the positive plate 220 is wound, the plurality of positive electrode sheets 220B are stacked to form a positive electrode sheet group 220A. The positions of the plurality of positive electrode sheets 220B and the lengths of the protruding directions are appropriately adjusted in consideration of the state in which the positive electrode sheet group 220A is connected to the positive electrode collector 320. In addition, the shape of the positive electrode sheet 220B is not limited to Fig.11 The shape illustrated in .

[0092] A positive electrode protection layer 223 is provided at the root of each of the plurality of positive electrode sheets 220B. The positive electrode protection layer 223 does not necessarily need to be provided at the root of the positive electrode sheet 220B.

[0093] In a typical example, the thickness of the negative electrode sheet 210B (one sheet) is smaller than the thickness of the positive electrode sheet 220B (one sheet). In this case, the thickness of the negative electrode sheet group 210A is smaller than the thickness of the positive electrode sheet group 220A.

[0094] (Connection Structure of Electrode Body 200 and Current Collector 300)

[0095] Fig.13 FIG. 2 is a diagram showing an electrode body 200 and a current collector 300 taken out of a secondary battery 1. Fig.13 As shown in FIG. 1 , the electrode body 200 is formed by stacking two electrode bodies 201 and 202, each of which is a wound electrode body. Fig.13 In the example shown, a structure in which two wound electrode bodies are stacked is shown, but the electrode body 200 may be composed of one wound electrode body, three or more wound electrode bodies, or a stacked electrode body.

[0096] The negative electrode sheet group 210A is joined to the negative electrode collector 310 at the joining portion 310A, and the positive electrode sheet group 220A is joined to the positive electrode collector 320 at the joining portion 320A. The joining portions 310A and 320A can be formed by, for example, ultrasonic welding, resistance welding, laser welding, riveting, or the like.

[0097] Fig.14 It is a diagram showing the connection structure between the negative electrode sheet group 210A and the negative electrode current collector 310 . Fig.15 , Fig.16 They are Fig.14 The front view and cross-sectional view of the connection structure shown.

[0098] like Figure 14 to Figure 16 As shown, the negative electrode current collector 310 is connected to the negative electrode terminal 131 between the electrode body 200 and the first sealing plate 121. The negative electrode current collector 310 includes a first conductive member 311 and a second conductive member 312. The first conductive member 311 and the second conductive member 312 are joined at a joint 313.

[0099] The negative electrode sheet group 210A is joined to the first conductive member 311 of the negative electrode current collector 310 at the joint 310A. The first conductive member 311 is connected to the second conductive member 312 at the joint 313. The joint 313 can be formed by, for example, ultrasonic bonding, resistance welding, laser welding, riveting, or the like.

[0100] The first conductive member 311 and the second conductive member 312 are attached to the inner surface side of the first sealing plate 121 via the resin insulating member 410. The insulating member 410 is provided so as to reach the inner surface side from the outer surface side of the first sealing plate 121 via the through hole provided in the first sealing plate 121. In addition, the insulating member 410 may be composed of a plurality of members including a member disposed between the negative electrode terminal 131 and the first sealing plate 121, and a member disposed between the first conductive member 311 and the second conductive member 312 and the first sealing plate 121.

[0101] The negative terminal 131 is mounted on the first sealing plate 121 via the insulating member 410. The negative terminal 131 is provided so as to be exposed outside the first sealing plate 121 and reach the second conductive member 312 of the negative electrode collector 310 provided on the inner surface side of the first sealing plate 121. The negative terminal 131 and the second conductive member 312 are joined at the joint 131A. The joint 131A can be formed by, for example, ultrasonic joining, resistance welding, laser welding, riveting, or the like.

[0102] As the assembly order of each component, first, the negative terminal 301 and the second conductive component 440 are mounted on the first sealing plate 121 together with the insulating component 410. Next, the first conductive component 311 connected to the electrode body 200 is mounted on the second conductive component 312. At this time, the first conductive component 311 is arranged on the insulating component 410 in a manner that a part of the first conductive component 311 overlaps with the second conductive component 312. Next, the first conductive component 311 and the second conductive component 312 are welded and connected at the joint 313.

[0103] The negative electrode terminal 131 may be electrically connected to the first sealing plate 121 . In addition, the first sealing plate 121 may also function as the negative electrode terminal 131 .

[0104] In addition, Figure 14 to Figure 16 In FIG. 1 , the negative electrode current collector 310 is exemplified as being composed of two members (the first conductive member 311 and the second conductive member 312 ), but the negative electrode current collector 310 may be composed of a single member.

[0105] exist Figure 14 to Figure 16 , the connection structure on the negative electrode side is shown, but the basic connection structure on the positive electrode side is also the same as that on the negative electrode side.

[0106] (Step of Inserting Electrode Body 200)

[0107] Fig.17 2 is a diagram showing the process of inserting the electrode body 200 into the case body 110. Fig.17 As shown, an insulating sheet 600 (electrode body holder) made of resin is arranged between the electrode body 200 and the case body 110 .

[0108] The insulating sheet 600 may be made of, for example, resin. More specifically, the insulating sheet 600 may be made of, for example, polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), or polyolefin (PO).

[0109] The insulating sheet 600 does not necessarily need to cover the entire surface of the electrode body 200. Preferably, the insulating sheet 600 covers 50% or more of the outer surface of the electrode body, and more preferably covers 70% or more of the area. Preferably, the insulating sheet 600 covers the entirety of at least four of the six surfaces of the substantially rectangular parallelepiped (flat) electrode body 200, except for the two surfaces each having the negative electrode sheet group 210A and the positive electrode sheet group 220A.

[0110] Fig.18 This is a diagram showing a step of placing the separator 510 between the first sealing plate 121 and the electrode body 200 . Fig.19 It is a cross-sectional view showing a state where the separator 510 is arranged between the first sealing plate 121 and the electrode body 200 .

[0111] like Fig.18 , Fig.19 As shown, the negative electrode sheet group 210A from the electrode body 200 toward the first sealing plate 121 is bent from the center of the first sealing plate 121 in the Y-axis direction toward the end, and then folded back toward the center. A separator 510 is provided to accommodate the bent negative electrode sheet group 210A (bent portion).

[0112] The spacer 510 includes a first spacer 511 and a second spacer 512. The first spacer 511 and the second spacer 512 are each slid along the Y-axis direction from the end side toward the center side of the first sealing plate 121 and engaged with each other. As a result, the spacer 510 is fixed to the first sealing plate 121 via the insulating member 410, and the stability of the position of the spacer 510 is increased.

[0113] like Fig.19 As shown, the separator 510 forms an internal space for accommodating the negative electrode current collector 310, and the front end portion of the negative electrode sheet group 210A is also accommodated in the internal space of the separator 510. The separator 510 has a hole portion for allowing the negative electrode sheet group 210A to pass through.

[0114] The material of the separator 510 is not particularly limited, but an insulating material such as resin is preferably used. More specifically, a sheet made of polyolefin (PO) is preferably used. Insulating sheet 600 may be interposed between separator 510 and electrode body 200 .

[0115] Refer again Fig.17In the manufacturing method of the secondary battery 1 of the present embodiment, after the negative electrode terminal 131 is electrically connected to the negative electrode sheet group 210A, the electrode body 200 is inserted into the case body 110 from the end side of the positive electrode sheet group 220A side through the first opening 111. When the electrode body 200 is inserted to a predetermined position of the case body 110, the positive electrode sheet group 220A protrudes from the second opening 112 of the case body 110 to the outside of the case body 110. Thus, after the electrode body 200 is inserted into the case body 110, the positive electrode terminal 132 and the positive electrode sheet group 220A can be connected.

[0116] When the negative electrode terminal 131 attached to the first sealing plate 121 is electrically connected to the negative electrode sheet group 210A after the electrode body 200 is inserted into the case body 110, the negative electrode sheet group 210A is required to have a length that allows the negative electrode sheet group 210A of the electrode body 200 housed in the case body 110 to sufficiently protrude to the outside of the case body 110. By electrically connecting the negative electrode terminal 131 attached to the first sealing plate 121 to the negative electrode sheet group 210A before the electrode body 200 is inserted into the case body 110, the length of the negative electrode sheet group 210A can be shortened compared to the case where the negative electrode terminal 131 attached to the first sealing plate 121 is attached after the electrode body 200 is inserted into the case body 110. As a result, the volume occupancy rate of the negative electrode plate 210 and the positive electrode plate 220 in the internal space of the case body 110 can be increased.

[0117] In addition, Fig.17 In the example, after the separator 510 for accommodating the bent portion of the negative electrode sheet group 210A is provided, the electrode body 200 is inserted into the case body 110. In this way, the bent portion of the negative electrode sheet group 210A can be protected during the insertion process of the electrode body 200.

[0118] In addition, Fig.17 In the example, the electrode body 200 is inserted into the case body 110 in a state where the electrode body 200 is covered by the insulating sheet 600 . Thus, it is possible to suppress damage to the electrode body 200 caused when the electrode body 200 is inserted into the case body 110 .

[0119] When the electrode body 200 is inserted, the case body 110 can be held at a predetermined angle. As one example, the electrode body 200 is preferably inserted in a state where the case body 110 is held so that the X-axis direction (the width direction of the case body 110) intersects with the horizontal direction at an angle of less than ±45°. For example, the case body 110 is tilted so that the upper end of the first opening 111 into which the electrode body 200 is inserted is located above the upper end of the second opening 112 in the vertical direction, so that the electrode body 200 can be inserted into the case body 110.

[0120] The step of inserting the electrode body 200 is not limited to a method of pressing the electrode body 200 from the first opening 111 side, and may be a method of pulling the electrode body 200 from the second opening 112 side, for example.

[0121] Fig. 20 5 is a diagram showing a modified example of the spacer 510. Figure 17 to Figure 19 In the example of FIG. 1 , a spacer 510 is provided at a portion of the first sealing plate 121 in the height direction (Z-axis direction). Fig. 20 As shown, the separator 510 may also be provided over substantially the entire area in the height direction of the first sealing plate 121. In this case, the separator 510 may also have a portion protruding toward the electrode body 200 side more than the vicinity of the negative electrode sheet group 210A (the second area) at a position separated from the negative electrode sheet group 210A in the Z-axis direction (the first area). A step difference (preferably a step difference of 1 mm or more) may also be formed at the boundary between the first area and the second area. In this way, damage to the negative electrode sheet group 210A caused when the electrode body 200 is inserted into the case body 110 can be suppressed.

[0122] (Mechanism for pressing the electrode body)

[0123] Fig.21 This is a diagram showing an example of a mechanism for pressing the electrode body 200 via the first sealing plate 121 and the separator 510A. Fig. 22 It means viewing from the Z axis direction Fig.21 The spacer 510A is a modified example of the spacer 510 described above.

[0124] like Fig.21 , Fig. 22 As shown, the separator 510A is arranged at a position avoiding the negative electrode sheet group 210A and the negative electrode collector 310 (a position separated from the negative electrode sheet group 210A and the negative electrode collector 310) in the height direction (Z-axis direction) of the first sealing plate 121 and the electrode body 200. More specifically, the separator 510A is arranged in two positions in a manner of clamping the negative electrode sheet group 210A in the Z-axis direction. However, the separator 510A can also be arranged only on one side of the negative electrode sheet group 210A in the Z-axis direction. The separator 510A can be fixed to the first sealing plate 121, for example, by bonding, welding, tape bonding, etc.

[0125] When the spacer 510A overlaps with the second liquid injection port 142 and the first exhaust valve 151 , in order to ensure the functions of the second liquid injection port 142 and the first exhaust valve 151 , it is preferable to provide a through hole, a cutout, a slit, etc. in the spacer 510A.

[0126] exist Fig.21 , Fig. 22In the example of , the electrode body 200 is inserted into the case body 110 by pressing the electrode body 200 via the separator 510A. The electrode body 200 may be further inserted by pressing the electrode body 200 via the separator 510A after a portion of the electrode body 200 is inserted into the case body 110, by preventing the separator 510A from contacting the electrode body 200 at the beginning of the insertion process of the electrode body 200.

[0127] Instead of the above-mentioned separator, a separator fixed to the electrode body 200 may be provided. The separator is fixed to the electrode body 200 by, for example, sticking with a tape.

[0128] In addition, from the perspective of protecting the positive electrode sheet group 220A, the separator 510 and the separator 510A may be disposed on the positive electrode sheet group 220A side. In the separator disposed on the positive electrode sheet group 220A side, an opening for passing the electrolyte is preferably provided at a position opposite to the second liquid injection port 142. The shape of the opening may be any shape as long as it allows the electrolyte to pass.

[0129] When comparing the thickness of the separator disposed on the negative electrode sheet group 210A side and the separator disposed on the positive electrode sheet group 220A side (the thickness in the direction connecting the first sealing plate 121 and the second sealing plate 122 (X-axis direction)), the space between the electrode body 200 and the sealing plate is larger on the second sealing plate 122 side than on the first sealing plate 121 side. Therefore, the thickness of the separator disposed on the positive electrode sheet group 220A side may be greater than the thickness of the separator disposed on the negative electrode sheet group 210A side.

[0130] Refer again Fig.18 and Fig.19 The negative electrode sheet group 210A is bent and connected to the negative electrode collector 310, and the negative electrode terminal 131 is connected to the negative electrode collector 310. Similarly, the positive electrode sheet group 220A is bent and connected to the positive electrode collector 320, and the positive electrode terminal 132 is connected to the positive electrode collector 320 (see Fig.21 ). Although it is preferred that the bonding surface between the negative electrode sheet group 210A and the negative electrode current collector 310 is arranged parallel to the first sealing plate 121, it is not necessarily parallel. For example, it is preferably arranged within a range of ±30 degrees. Similarly, although it is preferred that the bonding surface between the positive electrode sheet group 220A and the positive electrode current collector 320 is arranged parallel to the second sealing plate 122, it is not necessarily parallel. For example, it is preferably arranged within a range of ±30 degrees.

[0131] Here, refer to Figure 23 to Figure 25 Other types of spacers are shown in the drawings. Fig.23 is a three-dimensional diagram of another type of spacer 510B. Fig.24 is a three-dimensional diagram of another type of spacer 510C. Fig.25 2 is a perspective view of another type of separator 510D. The separators described below may be arranged on either the negative electrode sheet group 210A side or the positive electrode sheet group 220A side.

[0132] Fig.23 The separator 510B shown has a rectangular opening 510h1 on the side facing the electrode body 200. In the case of the separator 510B, the opening 510h1 is positioned facing the first liquid injection port 141 (or the second liquid injection port 142).

[0133] Fig.24 The separator 510C shown has an inclined slit-shaped opening 510h2 on the side facing the electrode body 200. When the slit-shaped opening 510h2 is provided, a sufficient opening area can be ensured, and the flow path area required for degassing and injection can be ensured, which has the advantage of preventing the injected electrolyte from accumulating.

[0134] Fig.25 The separator 510D shown is provided with a rectangular opening 510h3 at a position not opposite to the first injection port 141 (or the second injection port 142). The opening 510h3 is arranged at a position perpendicular to the bending direction of the electrode sheet. As a result, the curling of the diaphragm or the damage of the electrode (including the sheet) caused by the influence of the injection can be prevented, the pressing during the insertion of the electrode body can be made uniform, and the bent electrode sheet can be prevented from being squeezed out of the space in the separator.

[0135] The outer shape, opening position and shape of the separator are not limited to the above-mentioned separator, but by appropriately setting openings in the separator configured for the purpose of protecting the positive electrode sheet group 220A and the negative electrode sheet group 210A, it is possible to suppress damage to the electrode body, suppress unwanted short circuits, and suppress reduction in electrolyte injection properties.

[0136] When the first opening 111 is sealed by the first sealing plate 121, the negative terminal 131 is insulated from the first sealing plate 121. In this case, an insulating member such as a resin member may be disposed between the negative terminal 131 and the first sealing plate 121. In addition, the negative terminal 131 and the first sealing plate 121 may also be electrically connected. The first sealing plate 121 may also play the role of a negative terminal.

[0137] When the second opening 112 is sealed by the second sealing plate 122, the positive terminal 132 is insulated from the second sealing plate 122. In this case, an insulating member such as a resin member may be disposed between the positive terminal 132 and the second sealing plate 122. In addition, the positive terminal 132 and the second sealing plate 122 may also be electrically connected. The second sealing plate 122 may also function as a second electrode terminal.

[0138] (Manufacturing process of secondary battery 1)

[0139] Fig.26 1 is a flow chart showing each step of the method for manufacturing the secondary battery 1. Fig.26 As shown, in S10, the shell body 110 is prepared. Next, in S20, the electrode body 200 is made. In S30, the electrode terminals provided on the first sealing plate 121 and the second sealing plate 122 are electrically connected to the electrode sheet group of the electrode body 200. At this time, first, the negative terminal 131 is electrically connected to the negative electrode sheet group 210A (S31), and then, the separator 510 is arranged between the first sealing plate 121 on the negative electrode side and the electrode body 200 (S40), and then the electrode body 200 is inserted into the shell body 110 (S50). At this time, the positive electrode sheet group 220A protrudes from the second opening 112 of the shell body 110 to the outside of the shell body 110. After the electrode body 200 is inserted into the shell body 110, the positive terminal 132 is electrically connected to the positive electrode sheet group 220A (S32).

[0140] In this embodiment, an example is described in which the negative terminal 131 is connected to the negative electrode sheet group 210A (S31), the electrode body 200 is inserted (S50), and the positive terminal 132 is connected to the positive electrode sheet group 220A (S32). However, the scope of the present technology is not limited to this, and sometimes the process is carried out in the order of connecting the positive terminal 132 to the positive electrode sheet group 220A (S32), inserting the electrode body 200 (S50), and connecting the negative terminal 131 to the negative electrode sheet group 210A (S31).

[0141] After the connection between the electrode terminal and the electrode sheet group (S30) is completed, the first opening 111 and the second opening 112 are sealed (S60) by the first sealing plate 121 and the second sealing plate 122. The sealing process by the first sealing plate 121 and the second sealing plate 122 is performed by, for example, laser welding.

[0142] The process (S61) of sealing the first opening 111 using the first sealing plate 121 on the negative electrode side can be performed after the process (S50) of inserting the electrode body 200 into the shell body 110, and the process (S62) of sealing the second opening 112 using the second sealing plate 122 on the positive electrode side can be performed after the process (S32) of electrically connecting the positive terminal 132 to the positive electrode sheet group 220A.

[0143] Therefore, for example, the step (S61) of sealing the first opening 111 with the first sealing plate 121 may be performed before the step (S32) of electrically connecting the positive electrode terminal 132 to the positive electrode sheet group 220A, or the step (S61) of sealing the first opening 111 with the first sealing plate 121 may be performed after the step (S62) of sealing the second opening 112 with the second sealing plate 122. Furthermore, at least a part of the steps (S61, S62) of sealing with the first sealing plate 121 and the second sealing plate 122 may be performed simultaneously.

[0144] Next, a process (S70) of injecting electrolyte into the outer body 100 from the second injection hole 142 is performed. Since the first injection hole 141 is provided on the opposite side, it is preferable to use the first injection hole 141 as a vent for gas (air or nitrogen, etc.) in the outer body 100. Thus, it is possible to improve the injection property of the electrolyte into the outer body 100. Alternatively, the electrolyte may be injected from the first injection hole 141 and the gas may be exhausted from the second injection hole 142.

[0145] After the electrolyte is injected into the outer casing 100, the first filling hole 141 is sealed by the first sealing member 141a (first sealing step), and the second filling hole 142 is sealed by the second sealing member 142a (second sealing step). Either the first sealing step or the second sealing step may be performed first. The first sealing member 141a and the second sealing member 142a are fixed to the housing body 110 by riveting, for example, using blind rivets or other metal parts. Alternatively, the first sealing member 141a and the second sealing member 142a are fixed to the housing body 110 by welding.

[0146] Here, after performing one of the first sealing step and the second sealing step, a charging step of charging the electrode body 200 is performed, and after the charging step, the other of the first sealing step and the second sealing step is performed. After the through-holes on one side are sealed, charging is performed to discharge the generated gas to the outside of the outer casing 100. By sealing the through-holes on the other side thereafter, expansion of the outer casing 100 can be suppressed.

[0147] (Battery Pack 1000)

[0148] Reference Fig. 27 A battery pack 1000 using the above-described secondary battery 1 will be described. Fig. 271 is a schematic diagram showing the appearance of a battery pack 1000. The battery pack 1000 is a battery pack including a plurality of secondary batteries 1, wherein the long side direction of the first sealing plate 121 and the long side direction of the second sealing plate 122 are arranged to extend in the vertical direction, and a first exhaust valve 151 is arranged above the center (center in the height direction) of the first sealing plate 121 in the long side direction of the first sealing plate 121, and a second exhaust valve 152 is arranged above the center (center in the height direction) of the second sealing plate 122 in the long side direction of the second sealing plate 122.

[0149] According to the battery pack 1000, the batteries are arranged in such a manner that the faces of the largest areas of the secondary batteries 1 are oriented opposite to each other. A separator or the like may also be arranged between adjacent secondary batteries. Each secondary battery 1 may be connected in series or in parallel. The terminals of adjacent secondary batteries 1 are connected to each other by bus bars (not shown). The battery pack 1000 is fixed as a whole by a restraining member (not shown) that restrains the stacked secondary batteries 1. For example, a pair of end plates and a connecting rod or a box-shaped outer casing that connects them may also be used.

[0150] When the battery pack 1000 is mounted on a vehicle, the long sides of the first sealing plate 121 and the second sealing plate 122 are arranged in a direction extending in the vertical direction, so that the advantage of the low height of the battery pack 1000 can be fully utilized.

[0151] (summary)

[0152] The secondary battery 1 and the battery pack 1000 of the present embodiment can be summarized as follows.

[0153] The secondary battery 1 includes an electrode body 200 including a negative electrode plate 210 and a positive electrode plate 220 having a polarity different from that of the negative electrode plate 210, and an outer casing 100 accommodating the electrode body 200 and an electrolyte, the outer casing 100 including a first sealing plate 121 and a second sealing plate 122 disposed in a mutually opposed manner, the first sealing plate 121 including a first exhaust valve 151 for exhausting the gas in the outer casing 100 to the outside of the outer casing 100 when the pressure in the outer casing 100 becomes equal to or higher than a predetermined value, and the second sealing plate 122 including a second exhaust valve 152 for exhausting the gas in the outer casing 100 to the outside of the outer casing 100 when the pressure in the outer casing 100 becomes equal to or higher than a predetermined value. According to the secondary battery, a highly reliable secondary battery capable of appropriately exhausting gas can be provided.

[0154] In one example of a secondary battery 1, an outer casing 100 includes: a shell body 110 having a first opening 111 at one end thereof and a second opening 112 at the other end thereof; a first sealing plate 121 for sealing the first opening 111; and a second sealing plate 122 for sealing the second opening 112, wherein a negative electrode terminal 131 is provided on the first sealing plate 121, and a negative electrode terminal 131 is provided on the second sealing plate 122. A positive terminal 132 is provided, and the electrode body 200 includes a negative electrode sheet group 210A at one end thereof, and the negative electrode sheet group 210A is composed of a plurality of negative electrode sheets 210B electrically connected to the negative electrode plate 210, and the electrode body 200 includes a positive electrode sheet group 220A at the other end thereof, and the positive electrode sheet group 220A is composed of a plurality of positive electrode sheets 220B electrically connected to the positive electrode plate 220, and the negative electrode sheet group 210A is electrically connected to the negative terminal 131, and the positive electrode sheet group 220A is electrically connected to the positive terminal 132. According to this secondary battery, a secondary battery with higher volume energy density and high efficiency can be provided.

[0155] In one example of a secondary battery 1, in the long side direction of the first sealing plate 121, the first exhaust valve 151 is offset from the center of the first sealing plate 121 toward the first direction, and in the long side direction of the second sealing plate 122, the second exhaust valve 152 is offset from the center of the second sealing plate 122 toward the first direction.

[0156] In one example of the secondary battery 1, the shape of the first exhaust valve 151 in a plan view has a major axis and a minor axis, and the first exhaust valve 151 is arranged in a direction in which the major axis extends along the short side direction of the first sealing plate 121, and the center of the first exhaust valve 151 is arranged at a position deviated from the center of the first sealing plate 121 in the long side direction of the first sealing plate 121. According to this secondary battery, even if the outer casing 100 is deformed during normal use, the load on the exhaust valve can be reduced and the opening area for gas exhaust can be ensured.

[0157] The battery pack 1000 is a battery pack including a plurality of the secondary batteries 1 described above, wherein in the battery pack 1000, the long side directions of the first sealing plate 121 and the long side directions of the second sealing plate 122 are arranged in a manner extending in the vertical direction, the first exhaust valve 151 is arranged at a position higher than the center of the first sealing plate 121 in the vertical direction in the long side direction of the first sealing plate 121, and the second exhaust valve 152 is arranged at a position higher than the center of the second sealing plate 122 in the vertical direction in the long side direction of the second sealing plate 122. According to this battery pack, when mounted on a vehicle, by arranging the battery pack in a direction in which the long side directions of the first sealing plate 121 and the long side directions of the second sealing plate 122 extend in the vertical direction, the advantage of the low height of the battery pack 1000 can be fully utilized.

[0158] (Function and Effect)

[0159] According to the secondary battery 1 and the battery pack 1000 of the present embodiment, it is possible to provide a secondary battery and a battery pack with higher reliability.

[0160] Although the embodiments of the present invention have been described, the embodiments disclosed this time should be considered to be illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims, and it is intended to include all changes within the meaning and scope equivalent to the claims.

Claims

1. A secondary battery, characterized in that: have: an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; and an outer casing that contains the electrode body and the electrolyte, The outer casing includes a first wall and a second wall arranged to face each other. The first wall includes a first exhaust valve configured to exhaust the gas in the outer casing to the outside of the outer casing when the pressure in the outer casing reaches a predetermined value or more. The second wall includes a second exhaust valve configured to exhaust the gas in the outer casing to the outside of the outer casing when the pressure in the outer casing becomes equal to or higher than a predetermined value.

2. The secondary battery according to claim 1, characterized in that: The outer casing comprises: a housing body having a first opening at one end thereof and a second opening at the other end thereof; a first sealing plate for sealing the first opening; as well as a second sealing plate for sealing the second opening, The first wall is the first sealing plate, The second wall is the second sealing plate, The first sealing plate is provided with a first electrode terminal, The second sealing plate is provided with a second electrode terminal, The electrode body includes a first electrode sheet group at one end thereof, the first electrode sheet group being composed of a plurality of first electrode sheets electrically connected to the first electrode. The electrode body includes a second electrode sheet group at the other end thereof, the second electrode sheet group being composed of a plurality of second electrode sheets electrically connected to the second electrode. The first electrode sheet group is electrically connected to the first electrode terminal. The second electrode sheet group is electrically connected to the second electrode terminal.

3. The secondary battery according to claim 1 or 2, characterized in that: The first exhaust valve is arranged to be offset from the center of the first wall toward the first direction in the long side direction of the first wall. The second exhaust valve is arranged so as to be offset from the center of the second wall toward the first direction in the longitudinal direction of the second wall.

4. The secondary battery according to claim 1 or 2, characterized in that: The first exhaust valve has a shape having a major axis and a minor axis when viewed from above. The first exhaust valve is arranged in a direction in which the long axis direction extends along the short side direction of the first wall. The center of the first exhaust valve is arranged at a position offset from the center of the first wall in the longitudinal direction of the first wall.

5. A battery pack comprising a plurality of secondary batteries, The battery pack is characterized in that The secondary battery has: an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; and an outer casing that contains the electrode body and the electrolyte, The outer casing includes a first wall and a second wall arranged to face each other. The first wall includes a first exhaust valve configured to exhaust the gas in the outer casing to the outside of the outer casing when the pressure in the outer casing reaches a predetermined value or more. The second wall includes a second exhaust valve configured to exhaust the gas in the outer casing to the outside of the outer casing when the pressure in the outer casing reaches a predetermined value or more. In the battery pack, the secondary battery is arranged so that the long side direction of the first wall and the long side direction of the second wall extend in the vertical direction. The first exhaust valve is disposed at a position above the center of the first wall in the vertical direction in the longitudinal direction of the first wall. The second exhaust valve is disposed above the center of the second wall in the vertical direction in the longitudinal direction of the second wall.

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