Secondary battery and battery pack

Abstract

To provide a secondary battery and a battery pack with higher reliability.SOLUTION: A secondary battery 1 includes an electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode and an outer body that accommodates the electrode body and an electrolyte. The outer body includes a first sealing plate 121 and a second sealing plate arranged opposite each other. The first sealing plate 121 includes a first gas discharge valve 151 that discharges gas from within the outer body to outside the outer body when the pressure within the outer body reaches or exceeds a predetermined value. The second sealing plate includes a second gas discharge valve that discharges gas from within the outer body to outside the outer body when the pressure within the outer body reaches or exceeds a predetermined value.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present technology relates to a secondary battery and a battery pack. [Background technology]

[0002] Japanese Patent No. 4537353 (Patent Document 1) shows a rectangular 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 attached to cap plates (33, 33') that seal the openings (14a, 14b). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4537353 Summary of the Invention [Problem to be solved by the invention]

[0004] By using a rectangular battery with a positive terminal on one side of the battery case and a negative terminal on the other end, it is easy to make a low-height battery pack. However, there is a demand for secondary batteries with higher reliability. For example, the exhaust path for gas generated when an abnormality occurs in the secondary battery (thermal runaway, etc.) is limited. In addition, the amount of gas generated by secondary batteries in recent years has been increasing.

[0005] An object of the present technology is to provide a secondary battery and a battery pack having higher reliability. [Means for solving the problem]

[0006] The present technology provides the following secondary battery and battery pack.

[0007] [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 exterior body that contains the electrode body and an electrolyte, wherein the exterior body includes a first wall and a second wall arranged to face each other, the first wall including a first gas exhaust valve that exhausts gas within the exterior body to the outside of the exterior body when the pressure within the exterior body reaches or exceeds a predetermined value, and the second wall including a second gas exhaust that exhausts gas within the exterior body to the outside of the exterior body when the pressure within the exterior body reaches or exceeds a predetermined value.

[0008] [2] The secondary battery described in [1], wherein the exterior body includes a case main body having a first opening at one end and a second opening at the other end, a first sealing plate that seals the first opening, and a second sealing plate that seals the second opening, wherein the first wall is the first sealing plate and the second wall is the second sealing plate, a first electrode terminal is provided on the first sealing plate and a second electrode terminal is provided on the second sealing plate, the electrode body includes a first electrode tab group consisting of a plurality of first electrode tabs electrically connected to the first electrode at one end, and a second electrode tab group consisting of a plurality of second electrode tabs electrically connected to the second electrode at the other end, the first electrode tab group is electrically connected to the first electrode terminal, and the second electrode tab group is electrically connected to the second electrode terminal.

[0009] [3] The secondary battery described in [1] or [2], wherein in the longitudinal direction of the first wall, the first gas exhaust valve is positioned offset in a first direction from the center of the first wall, and in the longitudinal direction of the second wall, the second gas exhaust valve is positioned offset in the first direction from the center of the second wall.

[0010] [4] The secondary battery described in [1] or [2], wherein the first gas exhaust valve has a shape in a planar view having a major axis and a minor axis, the major axis is oriented to extend in the short direction of the first wall, and the center of the first gas exhaust valve is shifted from the center of the first wall in the longitudinal direction of the first wall.

[0011] [5] An assembled battery including a plurality of secondary batteries according to any one of [1] to [4], wherein in the assembled battery, a longitudinal direction of a first wall and a longitudinal direction of a second wall are arranged to extend in a vertical direction, a first gas exhaust valve is arranged above a vertical center of the first wall in the longitudinal direction of the first wall, and a second gas exhaust valve is arranged above a vertical center of the second wall in the longitudinal direction of the second wall. Effect of the Invention

[0012] According to the present technology, it is possible to provide a secondary battery and a battery pack with higher reliability. [Brief description of the drawings]

[0013] [Figure 1] FIG. [Diagram 2] 2 is a diagram showing the secondary battery shown in FIG. 1 as viewed from the direction of arrow II. [Diagram 3] 3 is a diagram showing the secondary battery shown in FIG. 1 as viewed from the direction of arrow III. [Figure 4] 4 is a diagram showing the secondary battery shown in FIG. 1 as viewed from the direction of arrow IV. [Diagram 5] 2 is a front cross-sectional view of the secondary battery shown in FIG. [Figure 6] 11A and 11B are diagrams showing other configurations of the first gas exhaust valve. [Figure 7] FIG. 2 is a front view showing a negative electrode original plate before the negative electrode plate is formed. [Figure 8] 8 is a cross-sectional view taken along the line VIII-VIII of the negative electrode original plate shown in FIG. 7. [Figure 9] FIG. 2 is a front view showing a negative electrode plate formed from the negative electrode original plate. [Figure 10] FIG. 2 is a front view showing a positive electrode original plate before the positive electrode plate is formed. [Figure 11] 11 is a cross-sectional view taken along the line XI-XI of the positive electrode plate shown in FIG. [Figure 12] FIG. 2 is a front view showing a positive electrode plate formed from a positive electrode original plate. [Figure 13]FIG. 2 is a diagram showing an electrode assembly and a current collector taken out from a secondary battery. [Figure 14] FIG. 4 is a diagram showing a connection structure between a negative electrode tab group and a negative electrode current collector. [Figure 15] FIG. 15 is a front view of the connection structure shown in FIG. [Figure 16] FIG. 15 is a cross-sectional view of the connection structure shown in FIG. [Figure 17] 11A to 11C are diagrams showing a process of inserting the electrode body into the case body. [Figure 18] 11A to 11C are diagrams showing a process of providing a spacer between the sealing plate and the electrode body. [Figure 19] 11 is a cross-sectional view showing a state in which a spacer is provided between a sealing plate and an electrode body. FIG. [Figure 20] FIG. 13 is a diagram showing a modified example of the spacer. [Figure 21] 13A and 13B are diagrams showing an example of a mechanism for pressing an electrode body via a sealing plate and a spacer. [Figure 22] 22 is a diagram showing the mechanism shown in FIG. 21 as viewed from the Z-axis direction. [Figure 23] FIG. 13 is a perspective view of a spacer of another embodiment. [Figure 24] FIG. 13 is a perspective view of a spacer of another embodiment. [Diagram 25] FIG. 13 is a perspective view of a spacer of another embodiment. [Figure 26] FIG. 2 is a flow chart showing each step of a method for producing a secondary battery. [Figure 27] FIG. 2 is a schematic diagram showing the appearance of a battery pack. [Figure 28] FIG. 4 corresponds to the view in FIG. 3 and shows another embodiment of the first sealing plate. [Figure 29] 5A and 5B correspond to the view in FIG. 4 and show other configurations of the second sealing plate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, embodiments of the present technology will be described. Note that the same or corresponding parts are denoted by the same reference characters, and description thereof will not be repeated.

[0015] In the embodiments described below, when referring to the number, amount, etc., the scope of the present technology is not necessarily limited to the number, amount, etc., unless otherwise specified. In addition, in the following embodiments, each component is not necessarily essential to the present technology, unless otherwise specified. In addition, the present technology is not necessarily limited to those that achieve all of the effects and advantages mentioned in the present embodiment.

[0016] In this specification, the words "comprise", "include" and "have" are open-ended, i.e., when a certain configuration is included, other configurations may or may not be included.

[0017] Furthermore, when geometric terms and terms expressing positional and directional relationships, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along" are used in this specification, these terms allow for manufacturing errors and slight variations. When terms expressing relative positional relationships, such as "upper side" and "lower side," are used in this specification, these terms are used to indicate relative positional relationships in one state, and the relative positional relationships can be inverted or rotated to any angle depending on the installation direction of each mechanism (for example, by turning the entire mechanism upside down).

[0018] In this specification, the term "battery" is not limited to lithium ion batteries, but may include other batteries such as nickel-metal hydride batteries and sodium ion batteries. In this specification, the term "electrode" may collectively refer to positive and negative electrodes. In addition, the term "electrode plate" may collectively refer to positive and negative plates.

[0019] (Overall battery configuration) Fig. 1 is a front view of a secondary battery 1 according to this embodiment. Figs. 2 to 4 are views of the secondary battery 1 shown in Fig. 1 as viewed from the directions of arrows II, III, and IV, respectively. Fig. 5 is a front cross-sectional view of the secondary battery 1 shown in Fig. 1. Fig. 28 corresponds to Fig. 3 and shows another embodiment of the first sealing plate, and Fig. 29 corresponds to Fig. 4 and shows another embodiment of the second sealing plate.

[0020] The secondary battery 1 can be mounted in an electric vehicle (BEV: Battery Electric Vehicle), a plug-in hybrid electric vehicle (PHEV: Plug-in Hybrid Electric Vehicle), a hybrid electric vehicle (HEV: Hybrid Electric Vehicle), etc. However, the use of the secondary battery 1 is not limited to being mounted on a vehicle.

[0021] 1 to 5, the secondary battery 1 includes an exterior body 100, an electrode assembly 200, and a current collector 300. The exterior body 100 includes a case main body 110, a first sealing plate 121 as a first wall, and a second sealing plate 122 as a second wall.

[0022] In this specification, the X-axis direction (first direction) shown in Figs. 1 to 5 may be referred to as the "width direction" of the secondary battery 1 or the case body 110, the Y-axis direction (second direction) may be referred to as the "thickness direction" of the secondary battery 1 or the case body 110, and the Z-axis direction (third direction) may be referred to as the "height direction" of the secondary battery 1 or the case body 110. In addition, in the description of this disclosure, the Z-axis direction is assumed to coincide with the vertical direction. Therefore, in the secondary battery 1 shown in Fig. 1, the upper side of the figure is vertically upward, and the lower side of the figure is vertically downward. Therefore, Fig. 2 shows the state as viewed from the bottom.

[0023] When configuring an assembled battery including the secondary batteries 1, multiple 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 restraining member to form a battery module, or the assembled battery may be directly supported on the side surface of a battery pack case without using a restraining member.

[0024] The case body 110 is made of a cylindrical, preferably rectangular, member. This results in a rectangular secondary battery 1. The case body 110 is made of metal. Specifically, the case body 110 is made of aluminum, an aluminum alloy, iron, an iron alloy, or the like.

[0025] 1 and 2, a first sealing plate 121 and a second sealing plate 122 are provided at both ends of the case body. The case body 110 can be formed into a square tube shape, for example, by abutting the edges of bent plate-like members (joint 110A shown in FIG. 2) and joining them together (for example, by laser welding). The corners of the "square tube" may have a rounded shape.

[0026] In this embodiment, the case body 110 is formed so that its length in the width direction (X-axis direction) of the secondary battery 1, that is, in the direction connecting the first sealing plate 121, which is the first wall, and the second sealing plate 122, which is the second wall (X-axis direction), is longer than the thickness direction (Y-axis direction) and height direction (Z-axis direction) of the secondary battery 1.

[0027] The dimension (width) of the case body 110 in the X-axis direction is preferably about 30 cm or more. This allows a relatively large (high capacity) secondary battery 1 to be constructed. The dimension (height) of the case body 110 in the Z-axis direction is preferably about 20 cm or less, more preferably about 15 cm or less, and even more preferably about 10 cm or less. This allows a relatively low height secondary battery 1 to be constructed, improving the mountability in a vehicle, for example.

[0028] As shown in FIG. 3, a first opening 111 is provided at one end of the case body 110. The first opening 111 is sealed by a first sealing plate 121. A negative electrode terminal 131 (first electrode terminal), a first liquid injection port 141, and a first gas exhaust valve 151 are provided at the first sealing plate 121. The positions of the negative electrode terminal 131 and the first gas exhaust valve 151 can be changed as appropriate. The first opening 111 and the first sealing plate 121 have a substantially rectangular shape with the Y-axis direction being the short side direction and the Z-axis direction being the long side direction. In this embodiment, the first gas exhaust valve 151 is disposed in the long side direction (Z direction) of the first sealing plate 121, shifted from the center CL of the first sealing plate 121 toward the first direction (vertically upward). As shown in FIG. 28, the first liquid injection port 141 may be provided on the opposite side to the first gas release valve 151 with respect to the negative electrode terminal 131 in the longitudinal direction (Z direction) of the first sealing plate 121.

[0029] As shown in FIG. 4, a second opening 112 is provided at one end of the case body 110. The second opening 112 is sealed by a second sealing plate 122. A positive electrode terminal 132 (second electrode terminal), a second liquid injection port 142, and a second gas exhaust valve 152 are provided at the second sealing plate 122. The positions of the positive electrode terminal 132 and the second gas exhaust valve 152 can be changed as appropriate. The second opening 112 and the second sealing plate 122 have a substantially rectangular shape with the Y-axis direction being the short side direction and the Z-axis direction being the long side direction. The second gas exhaust valve 152 is disposed offset from the center CL of the second sealing plate 122 toward the first direction (upward in the vertical direction) in the long side direction (Z direction) of the second sealing plate 122. As shown in FIG. 29, the second liquid injection port 142 may be provided on the opposite side to the second gas release valve 152 with respect to the positive electrode terminal 132 in the longitudinal direction (Z direction) of the second sealing plate 122.

[0030] In this way, by providing the first gas exhaust valve 151 and the second gas exhaust valve 152 on each of the opposing sealing plates, if an abnormality such as a short circuit occurs at one end of the electrode body 200 described below, and the gas exhaust valve is only located on the other side, there is a possibility that the exhaust of gas from inside the exterior body 100 to the outside will be delayed. On the other hand, by providing a gas exhaust valve on each of the first sealing plate 121 and the second sealing plate 122, it is possible to suppress a delay in gas exhaust even if an abnormality occurs at either end of the electrode body 200. This is particularly effective in secondary batteries that have a long length in the direction connecting the first sealing plate 121 and the second sealing plate 122 (X direction).

[0031] 3, the first gas exhaust valve 151 is preferably disposed at the center (center CL) of the first sealing plate 121 or above the center (at a position as far away from the center as possible). This is because it is possible to reduce the blowing out of excess solvent such as the electrolyte from the first gas exhaust valve 151 in the event of an abnormality. Furthermore, by disposing the first gas exhaust valve 151 at a position as far away from the center as possible, it is possible to reduce stress caused by deformation of the first sealing plate 121 (swelling of the center) during normal use.

[0032] A track-shaped gas exhaust valve is used as the first gas exhaust valve 151. The longitudinal direction of the track shape is arranged along the lateral direction of the first sealing plate 121, and the lateral direction of the track shape is arranged along the longitudinal direction of the first sealing plate 121. By adopting this arrangement, even if the exterior body 100 is deformed during normal use, it is possible to ensure the opening area while reducing the load on the first gas exhaust valve 151 (suppressing malfunction, changes in differential pressure, etc.). In addition, it is possible to increase the efficiency of the gas exhaust opening area when the first gas exhaust valve 151 functions with respect to the first sealing plate 121.

[0033] The first gas release valve 151 is provided with a track-shaped first break groove 151A that is thinner than the plate thickness of the first sealing plate 121, and a first auxiliary break groove 151B that extends vertically is provided in the center. In addition, a linear first weak portion 151C that is thinner than the thickness of the first auxiliary break groove 151B is provided. When the internal pressure of the exterior body 100 reaches a predetermined value or more, the first gas release valve 151 is determined from the first weak portion 151C and is further peeled off from the first sealing plate 121 along the first break groove 151A and the first auxiliary break groove 151B, thereby releasing the gas inside the exterior body 100 to the outside of the exterior body 100. The first weak portion 151C is not limited to a straight line, and may be a track-shaped portion that is along the inside of the first break groove 151A.

[0034] The second gas exhaust valve 152 is provided with a track-shaped second break groove 152A that is thinner than the plate thickness of the second sealing plate 122, and a second auxiliary break groove 152B that extends vertically is provided in the center. In addition, a linear second weak portion 152C that is thinner than the thickness of the second auxiliary break groove 152B is provided. When the internal pressure of the exterior body 100 reaches a predetermined value or more, the second gas exhaust valve 152 is determined from the second weak portion 152C and is further peeled off from the second sealing plate 122 along the second break groove 152A and the second auxiliary break groove 152B, thereby discharging the gas inside the exterior body 100 to the outside of the exterior body 100. The second weak portion 152C is not limited to a straight line, and may be a track-shaped portion that is along the inside of the second break groove 152A.

[0035] The first gas exhaust valve 151 and the second gas exhaust valve 152 are of the same shape and are provided at the same opposing positions, but may have different shapes, positions, valve opening pressures, etc. For example, when thermal runaway occurs in a secondary battery, it is effective to release the internal combustion of the thermal runaway secondary battery to the outside of the exterior body to prevent the internal combustion from spreading to adjacent secondary batteries in the same battery pack. In order to expel the internal combustion from the exterior body, it is preferable that the flow rate of the gas exhaust at the opening of the gas exhaust valve is high, which is synonymous with making the opening area small.

[0036] However, if the opening area of ​​the gas exhaust valve is small, the opening of the gas exhaust valve may be clogged with debris of the internally combusted electrode body, and exhaust may be delayed. Therefore, for example, by designing the opening area of ​​the second gas exhaust valve 152 to be greater than the opening area of ​​the first gas exhaust valve 151, it becomes possible to select such that the first gas exhaust valve 151, which has a small opening area, prioritizes the discharge of the internally combusted material of the contents (flow rate), and the second gas exhaust valve 152, which has a large opening area, prioritizes exhaust (flow rate). The ratio of the opening area of ​​the second gas exhaust valve 152 to the opening area of ​​the first gas exhaust valve 151 is preferably about 1.1.

[0037] 6, the first gas release valve 151 may be circular. Specifically, the first break groove 151A may be circular, and a circular first weak portion 151C may be provided along the inside of the first break groove 151A. The same can be applied to the second gas release valve 152.

[0038] First sealing plate 121 and second sealing plate 122 are made of metal. Specifically, first sealing plate 121 and second sealing plate 122 are made of aluminum, an aluminum alloy, iron, an iron alloy, or the like.

[0039] The negative electrode terminal 131 is electrically connected to the negative electrode of the electrode assembly 200. The positive electrode terminal 132 is electrically connected to the positive electrode of the electrode assembly 200.

[0040] The negative terminal 131 is made of a conductive material (more specifically, a metal), and may be made of, for example, copper or a copper alloy. The outer surface of the negative terminal 131 may be provided with a portion or layer made of aluminum or an aluminum alloy.

[0041] The positive electrode terminal 132 is made of a conductive material (more specifically, a metal), and may be made of, for example, aluminum or an aluminum alloy.

[0042] The electrode body 200 is a flat-shaped electrode body having a positive electrode plate and a negative electrode plate, which will be described later. Specifically, the electrode body 200 is a wound-type electrode body in which a band-shaped positive electrode plate and a band-shaped negative electrode plate are both wound via a band-shaped separator (not shown). However, in this specification, the "electrode body" is not limited to a wound-type electrode body, and may be a laminated electrode body in which a plurality of positive electrode plates and a plurality of negative electrode plates are alternately laminated. The electrode body may include a plurality of positive electrode plates and a plurality of negative electrode plates, and the positive electrode tabs provided on each positive electrode plate may be laminated to form a positive electrode tab group, or the negative electrode tabs provided on each negative electrode plate may be laminated to form a negative electrode tab group.

[0043] 5, the exterior body 100 houses the electrode body 200. The electrode body 200 is housed in the exterior body 100 so that the winding axis of the electrode body 200 is parallel to the X-axis direction.

[0044] Specifically, one or more wound electrode bodies are accommodated together with an electrolytic solution (electrolyte) (not shown) inside an insulating sheet 600 as a separator (described later) arranged in the exterior housing 100. As the electrolytic solution (non-aqueous electrolytic solution), for example, LiPF6 dissolved at a concentration of 1.2 mol / L in a non-aqueous solvent in which ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed in a volume ratio (25°C) of 30:30:40 can be used. Note that a solid electrolyte may be used instead of the electrolytic solution.

[0045] The electrode body 200 includes a negative electrode tab group 210A (first electrode tab group) provided at an end (first end) on the first sealing plate 121 side, and a positive electrode tab group 220A (second electrode tab group) provided at an end (second end) on the second sealing plate 122 side. The negative electrode tab group 210A and the positive electrode tab group 220A are connected to the negative electrode and positive electrode of the electrode body 200, respectively. The negative electrode tab group 210A and the positive electrode tab group 220A are formed so as to protrude from a main body portion of the electrode body 200 (a portion where a positive electrode plate and a negative electrode plate are stacked with a separator interposed therebetween) toward the first sealing plate 121 and the second sealing plate 122.

[0046] 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 made of a plate-shaped 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.

[0047] 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 tab group 210A and the negative electrode terminal 131. The negative electrode current collector 310 is made of a conductive material (more specifically, a metal), and may be made of, for example, copper or a copper alloy.

[0048] The positive electrode current collector 320 is disposed on the second sealing plate 122 via a resin insulating member. The positive electrode current collector 320 is electrically connected to the positive electrode tab group 220A and the positive electrode terminal 132. The positive electrode current collector 320 is made of a conductive material (more specifically, a metal), and may be made of, for example, aluminum or an aluminum alloy. The positive electrode tab group 220A may be electrically connected to the second sealing plate 122 directly or via the positive electrode current collector 320. In this case, the second sealing plate 122 may also serve as the positive electrode terminal 123.

[0049] (Configuration of electrode body 200) FIG. 7 is a front view showing the negative electrode original plate 210S before the negative electrode plate 210 (first electrode) is formed, FIG. 8 is a cross-sectional view taken along line VIII-VIII of the negative electrode original plate 210S shown in FIG. 7, and FIG. 9 is a front view showing the negative electrode plate 210 formed from the negative electrode original plate 210S.

[0050] The negative electrode plate 210 is manufactured by processing a negative electrode original plate 210S. As shown in Figures 6 and 7, 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.

[0051] A negative electrode active material layer 212 is formed on both sides of the negative electrode core 211 except for one end portion. The negative electrode active material layer 212 is formed by applying a negative electrode active material layer slurry with a die coater.

[0052] The negative electrode active material layer slurry is prepared by kneading graphite as the 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 approximately 98:1:1.

[0053] The negative electrode core 211 coated with the negative electrode active material layer slurry is dried to remove water contained in the negative electrode active material layer slurry, thereby forming the negative electrode active material layer 212. Furthermore, the negative electrode active material layer 212 is compressed to form a negative electrode original plate 210S including the negative electrode core 211 and 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 using energy beam irradiation, die processing, cutter processing, or the like.

[0054] As shown in Fig. 9, a plurality of negative electrode tabs 210B each made of a negative electrode core 211 are provided at one end in the width direction of a negative electrode plate 210 formed from a negative electrode original plate 210S. When the negative electrode plate 210 is wound, the plurality of negative electrode tabs 210B are stacked to form a negative electrode tab group 210A. The position and length in the protruding direction of each of the plurality of negative electrode tabs 210B are appropriately adjusted taking into consideration the state in which the negative electrode tab group 210A is connected to the negative electrode current collector 310. The shape of the negative electrode tab 210B is not limited to that exemplified in Fig. 9.

[0055] FIG. 10 is a front view showing the positive electrode original plate 220S before the positive electrode plate 220 (second electrode) is formed, FIG. 11 is a cross-sectional view taken along line XI-XI of the positive electrode original plate 220S shown in FIG. 10, and FIG. 12 is a front view showing the positive electrode plate 220 formed from the positive electrode original plate 220S.

[0056] The positive electrode plate 220 is manufactured by processing a positive electrode original plate 220S. As shown in Figures 10 and 11, 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.

[0057] A positive electrode active material layer 222 is formed on both sides of the positive electrode core 221 except for one end portion. The positive electrode active material layer 222 is formed on the positive electrode core 221 by applying a positive electrode active material layer slurry with a die coater.

[0058] The positive electrode active material layer slurry is prepared by kneading lithium nickel cobalt manganese composite oxide as the positive electrode active material, polyvinylidene fluoride (PVdF) as a binder, a carbon material as a conductive material, and N-methyl-2-pyrrolidone (NMP) as a dispersion medium, so that the mass ratio of lithium nickel cobalt manganese composite oxide:PVdF:carbon material is approximately 97.5:1:1.5.

[0059] The positive electrode protective layer 223 is in contact with the positive electrode core 221 and is formed at one end in the width direction of the positive electrode active material layer 222. The positive electrode protective layer 223 is formed on the positive electrode core 221 by applying a positive electrode protective layer slurry with a die coater. The positive electrode protective layer 223 has a larger electric resistance than the positive electrode active material layer 222.

[0060] The positive electrode protective layer slurry is 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 is approximately 83:3:14.

[0061] 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 active material layer 222 is compressed to form a 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. The positive electrode original plate 220S is cut into a predetermined shape to form the positive electrode plate 220. The positive electrode original plate 220S can be cut by laser processing using energy beam irradiation, die processing, cutter processing, or the like.

[0062] As shown in Fig. 12, a plurality of positive electrode tabs 220B made of a positive electrode core 221 are provided at one end in the width direction of the positive electrode plate 220 formed from the positive electrode original plate 220S. When the positive electrode plate 220 is wound, the plurality of positive electrode tabs 220B are stacked to form a positive electrode tab group 220A. The position and length in the protruding direction of each of the plurality of positive electrode tabs 220B are appropriately adjusted in consideration of the state in which the positive electrode tab group 220A is connected to the positive electrode current collector 320. The shape of the positive electrode tab 220B is not limited to that exemplified in Fig. 11.

[0063] A positive electrode protection layer 223 is provided at the base of each of the positive electrode tabs 220B. The positive electrode protection layer 223 does not necessarily have to be provided at the base of the positive electrode tab 220B.

[0064] In a typical example, the thickness of the negative electrode tab 210B (one piece) is smaller than the thickness of the positive electrode tab 220B (one piece). In this case, the thickness of the negative electrode tab group 210A is smaller than the thickness of the positive electrode tab group 220A.

[0065] (Connection structure between electrode body 200 and current collector 300) Fig. 13 is a diagram showing the electrode body 200 and the current collector 300 taken out from the secondary battery 1. As shown in Fig. 13, the electrode body 200 is formed by stacking two electrode bodies 201, 202, each of which is a wound type electrode body. In the example shown in Fig. 13, a structure in which two wound type electrode bodies are stacked is shown, but the electrode body 200 may be composed of one wound type electrode body, may be composed of three or more wound type electrode bodies, or may be composed of a laminated type electrode body.

[0066] The negative electrode tab group 210A is joined to the negative electrode current collector 310 at a joint 310A, and the positive electrode tab group 220A is joined to the positive electrode current collector 320 at a joint 320A. The joints 310A, 320A can be formed by, for example, ultrasonic bonding, resistance welding, laser welding, crimping, or the like.

[0067] Fig. 14 is a diagram showing a connection structure between negative electrode tab group 210A and negative electrode current collector 310. Fig. 15 and Fig. 16 are a front view and a cross-sectional view, respectively, of the connection structure shown in Fig. 14.

[0068] 14 to 16, 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.

[0069] The negative electrode tab group 210A is joined to a first conductive member 311 of the negative electrode current collector 310 at a joint 310A. The first conductive member 311 is connected to a second conductive member 312 at a joint 313. The joint 313 can be formed by, for example, ultrasonic bonding, resistance welding, laser welding, crimping, or the like.

[0070] 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 a resin insulating member 410. The insulating member 410 is provided so as to reach from the outer surface side to the inner surface side of the first sealing plate 121 via a through hole provided in the first sealing plate 121. Note that the insulating member 410 may be made up of multiple components including a member disposed between the negative electrode terminal 131 and the first sealing plate 121, and components disposed between the first conductive member 311 and the second conductive member 312 and the first sealing plate 121.

[0071] The negative electrode terminal 131 is attached to the first sealing plate 121 via an insulating member 410. The negative electrode terminal 131 is provided so as to be exposed to the outside of the first sealing plate 121 and to reach the second conductive member 312 of the negative electrode current collector 310 provided on the inner surface side of the first sealing plate 121. The negative electrode terminal 131 and the second conductive member 312 are joined at a joint 131A. The joint 131A can be formed by, for example, ultrasonic bonding, resistance welding, laser welding, crimping, or the like.

[0072] The procedure for assembling the components is as follows: first, the negative electrode terminal 301 and the second conductive member 440 are attached to the first sealing plate 121 together with the insulating member 410. Next, the first conductive member 311 connected to the electrode body 200 is attached to the second conductive member 312. At this time, the first conductive member 311 is placed on the insulating member 410 such that a portion of the first conductive member 311 overlaps with the second conductive member 312. Next, the first conductive member 311 and the second conductive member 312 are connected by welding at a joint 313.

[0073] However, the negative electrode terminal 131 may be electrically connected to the first sealing plate 121. Also, the first sealing plate 121 may play the role of the negative electrode terminal 131.

[0074] Although the negative electrode current collector 310 made up of two components (the first conductive member 311 and the second conductive member 312) is illustrated in FIGS. 14 to 16, the negative electrode current collector 310 may be made up of a single component.

[0075] Although the connection structure on the negative electrode side is shown in FIG. 14 and FIG. 14B, the basic connection structure on the positive electrode side is similar to that on the negative electrode side.

[0076] (Step of Inserting the Electrode Body 200) 17 is a diagram showing a process of inserting the electrode body 200 into the case body 110. As shown in FIG. 17, a resin insulating sheet 600 (electrode body holder) is disposed between the electrode body 200 and the case body 110.

[0077] The insulating sheet 600 may be made of, for example, resin. More specifically, the material of the insulating sheet 600 may be, for example, polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), or polyolefin (PO).

[0078] The insulating sheet 600 does not necessarily have to cover the entire surface of the electrode body 200. The insulating sheet 600 preferably covers an area of ​​about 50% or more, and more preferably about 70% or more, of the outer surface of the electrode body. Of the six faces of the approximately rectangular parallelepiped (flat) electrode body 200, the insulating sheet 600 preferably covers the entire four faces other than at least the two faces on which the negative electrode tab group 210A and the positive electrode tab group 220A are formed, respectively.

[0079] Fig. 18 is a diagram showing a process of arranging a spacer 510 between the first sealing plate 121 and the electrode body 200. Fig. 19 is a cross-sectional view showing a state in which the spacer 510 is arranged between the first sealing plate 121 and the electrode body 200.

[0080] 18 and 19, the negative electrode tab group 210A extending from the electrode body 200 toward the first sealing plate 121 is curved so as to extend from the center in the Y-axis direction of the first sealing plate 121 toward the end, and then turn back toward the center. A spacer 510 is provided to accommodate the curved negative electrode tab group 210A (curved portion).

[0081] The spacer 510 includes a first spacer 511 and a second spacer 512. The first spacer 511 and the second spacer 512 are engaged with each other by sliding them along the Y-axis direction from the end side toward the center side of the first sealing plate 121. In this way, 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.

[0082] 19, the spacer 510 forms an internal space for accommodating the negative electrode current collector 310, and the tip portion of the negative electrode tab group 210A is also accommodated in the internal space of the spacer 510. The spacer 510 has a hole that allows the negative electrode tab group 210A to pass therethrough.

[0083] The material of the spacer 510 is not particularly limited, but it is preferable to use an insulating material such as resin. More specifically, it is preferable to use a sheet made of polyolefin (PO). In addition, an insulating sheet 600 may be interposed between the spacer 510 and the electrode body 200.

[0084] 17 again, in the method for manufacturing the secondary battery 1 according to the present embodiment, after the negative electrode terminal 131 and the negative electrode tab group 210A are electrically connected, the electrode body 200 is inserted into the case body 110 from the end side on the positive electrode tab group 220A side through the first opening 111. When the electrode body 200 is inserted to a predetermined position in the case body 110, the positive electrode tab group 220A protrudes from the second opening 112 of the case body 110 to the outside of the case body 110. As a result, after the electrode body 200 is inserted into the case body 110, the positive electrode terminal 132 and the positive electrode tab group 220A can be connected.

[0085] When the negative electrode terminal 131 attached to the first sealing plate 121 and the negative electrode tab group 210A are electrically connected after the electrode body 200 is inserted into the case body 110, the negative electrode tab group 210A is required to have a length that allows the negative electrode tab group 210A of the electrode body 200 stored in the case body 110 to sufficiently protrude outside the case body 110. By electrically connecting the negative electrode terminal 131 attached to the first sealing plate 121 and the negative electrode tab group 210A before inserting the electrode body 200 into the case body 110, the length of the negative electrode tab group 210A can be reduced compared to the case where the electrode body 200 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.

[0086] 17, a spacer 510 for accommodating the curved portion of the negative electrode tab group 210A is provided, and then the electrode body 200 is inserted into the case body 110. In this manner, the curved portion of the negative electrode tab group 210A can be protected during the electrode body 200 insertion process.

[0087] 17, the electrode body 200 is inserted into the case body 110 in a state where the electrode body 200 is covered with the insulating sheet 600. This makes it possible to suppress damage to the electrode body 200 when it is inserted into the case body 110.

[0088] During the step of inserting the electrode body 200, the case body 110 can be held at a predetermined angle. As an example, it is preferable to insert the electrode body 200 in a state in which the case body 110 is held so that the X-axis direction (width direction of the case body 110) intersects with the horizontal direction at an angle of about ±45° or less. For example, the electrode body 200 can be inserted into the case body 110 with the case body 110 tilted so that the upper end of the first opening 111 into which the electrode body 200 is inserted is positioned higher than the upper end of the second opening 112 in the vertical direction.

[0089] The step of inserting the electrode body 200 is not limited to a mode in which the electrode body 200 is pushed in from the first opening 111 side, and may be a mode in which the electrode body 200 is pulled from the second opening 112 side, for example.

[0090] FIG. 20 is a diagram showing a modified example of the spacer 510. In the examples of FIGS. 17 to 19, the spacer 510 is provided in a part of the height direction (Z-axis direction) of the first sealing plate 121, but as shown in FIG. 20, the spacer 510 may be provided over substantially the entire area of ​​the height direction of the first sealing plate 121. In this case, the spacer 510 may have a portion that protrudes toward the electrode body 200 side from the vicinity of the negative electrode tab group 210A (second region) at a position (first region) spaced apart from the negative electrode tab group 210A in the Z-axis direction. A step (preferably a step of about 1 mm or more) may be formed at the boundary between the first region and the second region. In this way, damage to the negative electrode tab group 210A when the electrode body 200 is inserted into the case body 110 can be suppressed.

[0091] (Mechanism for pressing the electrode body) Fig. 21 is a diagram showing an example of a mechanism for pressing the electrode body 200 via the first sealing plate 121 and the spacer 510A. Fig. 22 is a diagram showing the mechanism shown in Fig. 21 as viewed from the Z-axis direction. The spacer 510A is a modified example of the spacer 510 described above.

[0092] 21 and 22, the spacer 510A is provided in a position (a position spaced apart from the negative electrode tab group 210A and the negative electrode current collector 310) avoiding the negative electrode tab group 210A and the negative electrode current collector 310 in the height direction (Z-axis direction) of the first sealing plate 121 and the electrode body 200. More specifically, the spacer 510A is provided in two separate locations so as to sandwich the negative electrode tab group 210A in the Z-axis direction. However, the spacer 510A may be provided only on one side of the negative electrode tab group 210A in the Z-axis direction. The spacer 510A can be fixed to the first sealing plate 121 by a method such as adhesion, welding, or taping.

[0093] When spacer 510A overlaps with second liquid inlet 142 and first gas exhaust valve 151, it is preferable to provide spacer 510A with a through hole, a notch, a slit, or the like so as to ensure the functions of second liquid inlet 142 and first gas exhaust valve 151.

[0094] 21 and 22, the electrode body 200 is inserted into the case body 110 by pressing the electrode body 200 via the spacer 510A. The spacer 510A may not be brought into contact with the electrode body 200 at the beginning of the insertion process of the electrode body 200, and after a portion of the electrode body 200 has been inserted into the case body 110, the electrode body 200 may be further inserted by pressing the electrode body 200 via the spacer 510A.

[0095] Instead of the above-mentioned spacers, spacers may be provided that are fixed to the electrode assembly 200. The spacers are fixed to the electrode assembly 200 by, for example, attaching a tape.

[0096] From the viewpoint of protecting the positive electrode tab group 220A, the spacer 510 and the spacer 510A may be provided on the positive electrode tab group 220A side. It is also preferable that the spacer to be provided on the positive electrode tab group 220A side has an opening for passing the electrolyte at a position facing the second liquid injection port 142. The shape of the opening may be any shape as long as it allows the electrolyte to pass through.

[0097] When comparing the thickness (thickness in the direction connecting first sealing plate 121 and second sealing plate 122 (X-axis direction)) of the spacer arranged on the negative electrode tab group 210A side and the spacer arranged on the positive electrode tab group 220A side, 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, it is preferable that the thickness of the spacer arranged on the positive electrode tab group 220A side is larger than the thickness of the spacer arranged on the negative electrode tab group 210A side.

[0098] 18 and 19, the negative electrode tab group 210A is bent and connected to the negative electrode current collector 310, and the negative electrode terminal 131 is connected to the negative electrode current collector 310. Similarly, the positive electrode tab group 220A is bent and connected to the positive electrode current collector 320, and the positive electrode terminal 132 is connected to the positive electrode current collector 320 (see FIG. 21). The joint surfaces of the negative electrode tab group 210A and the negative electrode current collector 310 are preferably arranged in parallel along the first sealing plate 121, but do not necessarily have to be parallel. For example, they are preferably arranged within a range of ±30 degrees. Similarly, the joint surfaces of the positive electrode tab group 220A and the positive electrode current collector 320 are preferably arranged in parallel along the second sealing plate 122, but do not necessarily have to be parallel. For example, they are preferably arranged within a range of ±30 degrees.

[0099] Here, spacers of other configurations are illustrated with reference to Fig. 23 to Fig. 25. Fig. 23 is a perspective view of a spacer 510B of another configuration, Fig. 24 is a perspective view of a spacer 510C of another configuration, and Fig. 25 is a perspective view of a spacer 510D of another configuration. The spacers shown below can be disposed on either the negative electrode tab group 210A side or the positive electrode tab group 220A side.

[0100] 23 has a rectangular opening 510h1 provided on the side facing the electrode body 200. In the case of this spacer 510B, the opening 510h1 is located at a position facing the first liquid inlet 141 (or the second liquid inlet 142).

[0101] 24 is provided with a slit-shaped opening 510h2 arranged obliquely on the side facing the electrode body 200. When the slit-shaped opening 510h2 is provided, a sufficient opening area is ensured, and the flow path area required for degassing and injection is ensured, and further, there is an advantage that the injected electrolyte is less likely to accumulate.

[0102] 25 has a rectangular opening 510h3 at a position not facing the first liquid inlet 141 (or the second liquid inlet 142). The position of this opening 510h3 is perpendicular to the curved direction of the electrode tab. As a result, curling of the separator and damage to the electrode (including the tab) due to the force of the liquid inlet can be prevented, pressure can be uniformed when inserting the electrode body, and the curved electrode tab can be prevented from protruding from the space inside the spacer.

[0103] The outer shape of the spacer and the position and shape of the openings are not limited to those of the above spacer, but by providing appropriate openings in the spacer arranged for the purpose of protecting the negative electrode tab group 210A and the positive electrode tab group 220A, it is possible to suppress damage to the electrode body, or suppress unintended short circuits, and suppress deterioration of the electrolyte injectability.

[0104] When the first opening 111 is sealed with the first sealing plate 121, the negative electrode terminal 131 and the first sealing plate 121 are insulated from each other. In this case, an insulating member such as a resin member may be disposed between the negative electrode terminal 131 and the first sealing plate 121. The negative electrode terminal 131 and the first sealing plate 121 may be electrically connected. The first sealing plate 121 may also function as the negative electrode terminal.

[0105] When the second opening 112 is sealed with the second sealing plate 122, the positive electrode terminal 132 and the second sealing plate 122 are insulated from each other. In this case, an insulating member such as a resin member may be disposed between the positive electrode terminal 132 and the second sealing plate 122. The positive electrode terminal 132 and the second sealing plate 122 may be electrically connected to each other. The second sealing plate 122 may serve as the second electrode terminal.

[0106] (Manufacturing process of secondary battery 1) FIG. 26 is a flow diagram showing each step of the manufacturing method of the secondary battery 1. As shown in FIG. 26, in S10, the case body 110 is prepared. Next, in S20, the electrode body 200 is produced. In S30, the electrode terminals provided on the first sealing plate 121 and the second sealing plate 122 are electrically connected to the electrode tab group of the electrode body 200. At this time, the negative electrode terminal 131 and the negative electrode tab group 210A are first electrically connected (S31), and then the spacer 510 is placed between the first sealing plate 121 on the negative electrode side and the electrode body 200 (S40), and further the electrode body 200 is inserted into the case body 110 (S50). At this time, the positive electrode tab group 220A protrudes to the outside of the case body 110 from the second opening 112 of the case body 110. After the electrode body 200 is inserted into the case body 110, the positive electrode terminal 132 and the positive electrode tab group 220A are electrically connected (S32).

[0107] In the present embodiment, an example has been described in which the steps are performed in the order of connection (S31) between the negative electrode terminal 131 and the negative electrode tab group 210A, insertion (S50) of the electrode body 200, and connection (S32) between the positive electrode terminal 132 and the positive electrode tab group 220A. However, the scope of the present technology is not limited to this, and there are also cases in which the steps are performed in the order of connection (S32) between the positive electrode terminal 132 and the positive electrode tab group 220A, insertion (S50) of the electrode body 200, and connection (S31) between the negative electrode terminal 131 and the negative electrode tab group 210A.

[0108] After the connection between the electrode terminals and the electrode tab group (S30) is completed, the first opening 111 and the second opening 112 are sealed with the first sealing plate 121 and the second sealing plate 122 (S60). The sealing step with the first sealing plate 121 and the second sealing plate 122 is performed by, for example, laser welding.

[0109] The process (S61) of sealing the first opening 111 with the first sealing plate 121 on the negative electrode side may be performed after the process (S50) of inserting the electrode body 200 into the case body 110, and the process (S62) of sealing the second opening 112 with the second sealing plate 122 on the positive electrode side may be performed after the process (S32) of electrically connecting the positive electrode terminal 132 and the positive electrode tab group 220A.

[0110] Therefore, for example, the step (S61) of sealing first opening 111 with first sealing plate 121 may be performed before the step (S32) of electrically connecting positive electrode terminal 132 and positive electrode tab group 220A, or the step (S61) of sealing first opening 111 with first sealing plate 121 may be performed after the step (S62) of sealing second opening 112 with second sealing plate 122. Furthermore, at least some of the steps (S61, S62) of sealing with first sealing plate 121 and second sealing plate 122 can be performed simultaneously.

[0111] Next, a step (S70) is performed of injecting the electrolyte into the exterior body 100 from the second liquid injection port 142. Since the first liquid injection port 141 is provided on the opposite side, it is preferable to use this first liquid injection port 141 as an exhaust hole for gas (air, nitrogen, etc.) inside the exterior body 100. This can improve the injection of the electrolyte into the exterior body 100. Alternatively, the electrolyte may be injected from the first liquid injection port 141, and the gas may be exhausted from the second liquid injection port 142.

[0112] After the injection of the electrolyte into the exterior body 100 is completed, the first liquid inlet 141 is sealed with the first sealing member 141a (first sealing step), and the second liquid inlet 142 is sealed with 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 case body 110 by crimping using, for example, blind rivets or other metal members. Alternatively, the first sealing member 141a and the second sealing member 142a are fixed to the case body 110 by welding.

[0113] Here, after one of the first sealing step and the second sealing step is performed, a charging step is performed in which the electrode body 200 is charged, and after this charging step, the other of the first sealing step and the second sealing step is performed. After sealing the through hole on one side, charging is performed and the generated gas is exhausted to the outside of the exterior body 100. Thereafter, by sealing the through hole on the other side, swelling of the exterior body 100 can be suppressed.

[0114] (Battery pack 1000) With reference to Fig. 27, a battery pack 1000 using the secondary battery 1 described above will be described. Fig. 27 is a schematic diagram showing the appearance of the battery pack 1000. The battery pack 1000 is an assembled battery including a plurality of secondary batteries 1, and is arranged such that the longitudinal direction of a first sealing plate 121 and the longitudinal direction of a second sealing plate 122 extend in the vertical direction, and a first gas release valve 151 is arranged above the center (center in the height direction) of the first sealing plate 121 in the longitudinal direction of the first sealing plate 121, and a second gas release valve 152 is arranged above the center (center in the height direction) of the second sealing plate 122 in the longitudinal direction of the second sealing plate 122.

[0115] In this battery pack 1000, the secondary batteries 1 are arranged so that the faces with the largest areas of the batteries face each other. A separator or the like may be placed between adjacent secondary batteries. The secondary batteries 1 may be connected in series or parallel. The terminals of adjacent secondary batteries 1 are connected to each other by a bus bar (not shown). The battery pack 1000 is fixed together by a restraining member (not shown) that restrains the stacked secondary batteries 1. For example, a pair of end plates and a bind bar connecting them, or a box-shaped exterior case may be used.

[0116] When this battery pack 1000 is mounted on a vehicle, the advantage of the low height of battery pack 1000 can be fully utilized by arranging the longitudinal direction of first sealing plate 121 and the longitudinal direction of second sealing plate 122 to extend vertically.

[0117] (summary) The above-mentioned contents regarding the secondary battery 1 and the battery pack 1000 according to this embodiment can be summarized as follows.

[0118] The secondary battery 1 includes an electrode assembly 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 exterior body 100 that contains the electrode assembly 200 and an electrolyte, the exterior body 100 including a first sealing plate 121 and a second sealing plate 122 that are arranged to face each other, the first sealing plate 121 including a first gas exhaust valve 151 that exhausts gas in the exterior body 100 to the outside of the exterior body 100 when the pressure in the exterior body 100 reaches or exceeds a predetermined value, and the second sealing plate 122 including a second gas exhaust valve 152 that exhausts gas in the exterior body 100 to the outside of the exterior body 100 when the pressure in the exterior body 100 reaches or exceeds a predetermined value. This secondary battery makes it possible to provide a highly reliable secondary battery that can appropriately exhaust gas.

[0119] In one example of a secondary battery 1, an exterior body 100 includes a case main body 110 having a first opening 111 at one end and a second opening 112 at the other end, a first sealing plate 121 that seals the first opening 111, and a second sealing plate 122 that seals the second opening 112, a negative electrode terminal 131 is provided on the first sealing plate 121, and a positive electrode terminal 132 is provided on the second sealing plate 122, an electrode body 200 includes, at one end, a negative electrode tab group 210A consisting of a plurality of negative electrode tabs 210B electrically connected to a negative electrode plate 210, and a positive electrode tab group 220A consisting of a plurality of positive electrode tabs 220B electrically connected to a positive electrode plate 220, the negative electrode tab group 210A is electrically connected to the negative electrode terminal 131, and the positive electrode tab group 220A is electrically connected to the positive electrode terminal 132. This secondary battery has a higher volumetric energy density, making it possible to provide an efficient secondary battery.

[0120] In one example of a secondary battery 1, in the longitudinal direction of the first sealing plate 121, the first gas exhaust valve 151 is positioned offset from the center of the first sealing plate 121 toward the first direction, and in the longitudinal direction of the second sealing plate 122, the second gas exhaust valve 152 is positioned offset from the center of the second sealing plate 122 toward the first direction.

[0121] In the secondary battery 1 according to the example, the first gas release valve 151 has a shape in a plan view with a major axis and a minor axis, and is disposed so that the major axis extends in the short direction of the first sealing plate 121, and the center of the first gas release valve 151 is disposed at a position shifted from the center of the first sealing plate 121 in the longitudinal direction of the first sealing plate 121. With this secondary battery, even if the exterior body 100 is deformed during normal use, it is possible to ensure an opening area for gas release while reducing the load on the gas release valve.

[0122] Battery assembly 1000 is an assembled battery including a plurality of any of the secondary batteries 1 described above, in which first sealing plate 121 and second sealing plate 122 are arranged such that their longitudinal directions extend in the vertical direction, first gas release valve 151 is arranged above the vertical center of first sealing plate 121 in the longitudinal direction of first sealing plate 121, and second gas release valve 152 is arranged above the vertical center of second sealing plate 122 in the longitudinal direction of second sealing plate 122. When this assembled battery is mounted on a vehicle, the longitudinal directions of first sealing plate 121 and second sealing plate 122 are arranged such that the longitudinal directions of first sealing plate 121 and second sealing plate 122 extend in the vertical direction, thereby making it possible to fully utilize the advantage of the low height of battery assembly 1000.

[0123] (Action and effect) The secondary battery 1 and the battery pack 1000 according to this embodiment make it possible to provide a secondary battery and a battery pack with higher reliability.

[0124] Although the embodiment of the present technology has been described above, the embodiment disclosed herein should be considered as illustrative and not restrictive in all respects. The scope of the present technology is defined by the claims, and it is intended to include all modifications within the scope and meaning equivalent to the claims. [Explanation of symbols]

[0125] 1 secondary battery, 100 exterior body, 110 case body, 110A joint, 111 first opening, 112 second opening, 121 first sealing plate, 122 second sealing plate, 131 negative electrode terminal, 131A joint, 132 positive electrode terminal, 141 first liquid filling port, 142 second liquid filling port, 151 first gas exhaust valve, 151A first break groove, 151B first auxiliary break groove, 151C first weak portion, 152 second gas exhaust valve, 152A second break groove, 152B second auxiliary break groove, 152C second weak portion, 200, 201, 202 electrode body, 210 negative electrode plate, 210A negative electrode tab group, 210B negative electrode tab, 210S negative electrode original plate, 211 negative electrode core, 212 Negative electrode active material layer, 220 positive electrode plate, 220A positive electrode tab group, 220B positive electrode tab, 220S positive electrode original plate, 221 positive electrode core, 222 positive electrode active material layer, 223 positive electrode protective layer, 300 current collector, 310 negative electrode current collector, 310A joint, 311 first conductive member, 312 second conductive member, 313 joint, 320 positive electrode current collector, 320A joint, 410 insulating member, 411 first insulating member, 412 second insulating member, 510, 510A, 510B, 510C, 510D spacers, 510B1, 510C1 protrusions, 510D1 joint, 511 first spacer, 512 second spacer, 600 insulating sheet, 1000 assembled battery.

Claims

1. An electrode body including a first electrode and a second electrode having a polarity different from that of the first electrode; an exterior body that accommodates the electrode assembly and an electrolyte; Equipped with The exterior body includes a first wall and a second wall arranged to face each other, the first wall includes a first gas exhaust valve that exhausts gas inside the exterior body to the outside of the exterior body when pressure inside the exterior body reaches or exceeds a predetermined value; the second wall includes a second gas exhaust valve that exhausts gas inside the exterior body to the outside of the exterior body when the pressure inside the exterior body reaches or exceeds a predetermined value. Secondary battery.

2. The exterior body is a case body having a first opening at one end and a second opening at the other end; a first sealing plate that seals the first opening; a second sealing plate that seals the second opening, the first wall is the first sealing plate, the second wall is the second sealing plate, a first electrode terminal is provided on the first sealing plate; The second sealing plate is provided with a second electrode terminal, The electrode body is a first electrode tab group including a plurality of first electrode tabs electrically connected to the first electrodes at one end; a second electrode tab group including a plurality of second electrode tabs electrically connected to the second electrodes at the other end, the first electrode tab group is electrically connected to the first electrode terminals, the second electrode tab group is electrically connected to the second electrode terminals; The secondary battery according to claim 1 .

3. In a longitudinal direction of the first wall, the first gas exhaust valve is disposed offset from a center of the first wall toward a first direction side, In the longitudinal direction of the second wall, the second gas exhaust valve is disposed offset from the center of the second wall toward the first direction. The secondary battery according to claim 1 or 2.

4. The first gas exhaust valve has a shape in a plan view having a major axis and a minor axis, The long axis is oriented to extend in a short direction of the first wall, In the longitudinal direction of the first wall, a center of the first gas exhaust valve is disposed at a position shifted from a center of the first wall. The secondary battery according to claim 1 or 2.

5. A battery pack including a plurality of the secondary batteries according to claim 1, In the battery pack, a longitudinal direction of the first wall and a longitudinal direction of the second wall are arranged to extend in a vertical direction, The first gas exhaust valve is disposed above a center of the first wall in a vertical direction in a longitudinal direction of the first wall, In the longitudinal direction of the second wall, the second gas exhaust valve is disposed above a center of the second wall in a vertical direction. Battery pack.

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