Secondary battery module

Abstract

A secondary battery module is provided. In a first state of a plurality of cells (1) in the secondary battery module, an electrode body (200) has a first thickness (T201) in a first direction, and in a second state of the plurality of cells (1), the electrode body (200) has a second thickness (T202) in the first direction, the second thickness (T202) is greater than the first thickness (T201) by a thickness of 1.5% or more of a size of a first face (S1) in the first direction, a first plate thickness (T1) of a case (100) is greater than a second plate thickness (T2), a first corner portion (C1) of the case (100) has a first radius of curvature (R1), a second corner portion (C2) has a second radius of curvature (R2), and the first radius of curvature (R1) and the second radius of curvature (R2) are 0.5 mm or less.

Description

Technical Field

[0001] This technology relates to secondary battery modules. Background Technology

[0002] As a temperature control mechanism for secondary batteries, the structure described in Japanese Patent Publication No. 2022-540234 can be cited as an example.

[0003] The aim is to achieve efficient temperature control for secondary batteries. This involves maintaining high thermal conductivity between the battery and temperature control components, even as the electrodes expand and contract during charging and discharging, causing deformation of the casing housing the electrodes. From this perspective, existing temperature control mechanisms still have room for improvement. Summary of the Invention

[0004] The purpose of this technology is to provide a secondary battery module capable of efficient temperature control.

[0005] This technology provides the following secondary battery modules.

[0006] [1] A secondary battery module comprising: a plurality of batteries, each comprising an electrode body and a square housing housing the electrode body, and arranged along a first direction; a temperature control component for controlling the temperature of the plurality of batteries; and a heat-conducting layer sandwiched between the plurality of batteries and the temperature control component in a second direction orthogonal to the first direction, wherein the housing has: a first surface having a first plate thickness extending in a direction orthogonal to the second direction and at least a portion in contact with the heat-conducting layer; a second surface having a second plate thickness extending in a direction orthogonal to the first surface; a third surface extending parallel to the second surface and facing the second surface in the first direction; and a first corner portion, which is located in the housing. The outer surface of the body is disposed between the first surface and the second surface; and the second corner portion is disposed between the first surface and the third surface on the outer surface of the housing. In the first state of the plurality of batteries, the electrode body has a first thickness in the first direction. In the second state of the plurality of batteries, the electrode body has a second thickness in the first direction. The second thickness is greater than the first thickness by more than 1.5% of the dimension of the first surface in the first direction. The first plate thickness of the housing is greater than the second plate thickness. The first corner portion of the housing has a first radius of curvature, and the second corner portion has a second radius of curvature. The first radius of curvature and the second radius of curvature are 0.5 mm or less.

[0007] [2] In the secondary battery module described in [1], the thickness of the first plate is less than twice the thickness of the second plate.

[0008] [3] In the secondary battery module described in [1] or [2], the inner surface of the first surface and the electrode body are separated from each other in the second direction by more than 30% of the thickness of the first plate.

[0009] [4] In any of the secondary battery modules described in [1] to [3], the housing includes: a housing body, which is cylindrical, includes the first surface to the third surface, and has a first opening and a second opening at both ends in a third direction orthogonal to the first direction and the second direction; and a first sealing plate and a second sealing plate, which respectively seal the first opening and the second opening.

[0010] [5] In the secondary battery module described in [4], the first surface of the housing has a size of 300 mm or more in the third direction.

[0011] [6] In any of the secondary battery modules described in [1] to [5], the electrode body is a stacked electrode body formed by stacking a positive electrode and a negative electrode through a separator.

[0012] [7] In any of the secondary battery modules described in [1] to [6], the heat-conducting layer is disposed at a position including the first surface at the center in the first direction.

[0013] [8] In any of the secondary battery modules described in [1] to [7], the first radius of curvature and the second radius of curvature are 0.2% or more of the dimension of the first surface in the first direction.

[0014] [9] In any of the secondary battery modules described in [1] to [8], a gas discharge valve is provided on the first surface of the housing.

[0015] The above and other objects, features, aspects and advantages of the invention will become clear from the following detailed description in relation to the invention, which is understood in conjunction with the accompanying drawings. Attached Figure Description

[0016] Figure 1 This is a front view showing the structure of a secondary battery according to one embodiment.

[0017] Figure 2 This indicates viewing from the direction of arrow II. Figure 1 The diagram shows the state of the secondary battery.

[0018] Figure 3 This indicates viewing from the direction of arrow III. Figure 1 The diagram shows the state of the secondary battery.

[0019] Figure 4 yes Figure 1The image shows a front cross-sectional view of a secondary battery.

[0020] Figure 5 This is the front view of the negative electrode plate.

[0021] Figure 6 This is the front view of the positive electrode plate.

[0022] Figure 7 This is a diagram showing the structure of the battery module.

[0023] Figure 8 This is a cross-sectional view of the bottom of the casing of a secondary battery in the first state according to one embodiment.

[0024] Figure 9 This is a cross-sectional view of the bottom of the casing of a secondary battery in a second state according to one embodiment.

[0025] Figure 10 This is a cross-sectional view of the bottom of the casing of the secondary battery in the second state of the comparative example.

[0026] Figure 11 This is a diagram illustrating the method for calculating the thickness of the electrode body.

[0027] Figure 12 This diagram shows the configuration of the heat-conducting layer on the bottom surface of the casing and the gas exhaust valve.

[0028] Figure 13 This is a cross-sectional view of a secondary battery showing the structure of the electrodes and the configuration of the gas discharge valve.

[0029] Figure 14 This is a front cross-sectional view of the battery module involved in the variation example. Detailed Implementation

[0030] The embodiments of this technology will be described below. Additionally, there are instances where the same or equivalent parts are labeled with the same reference numerals in the accompanying drawings, and their descriptions are not repeated.

[0031] Furthermore, in the embodiments described below, when numbers, quantities, etc., are mentioned, the scope of this technology is not necessarily limited to those numbers, quantities, etc., unless specifically stated otherwise. Additionally, in the embodiments described below, each structural element is not necessarily essential to this technology, unless specifically stated otherwise. Furthermore, this technology is not limited to technologies that achieve all the effects mentioned in these embodiments.

[0032] Furthermore, in this specification, the terms "comprise," "include," and "have" are open-ended. That is, when a structure is included, other structures besides that structure may be included, or other structures besides that structure may not be included.

[0033] Furthermore, in this specification, when using geometric terms and terms indicating positional or directional relationships, such as "parallel," "orthogonal," "45° oblique," "coaxial," and "along," these terms allow for manufacturing errors or slight variations. In this specification, when using terms indicating relative positional relationships such as "upper side" and "lower side," these terms are used to indicate the relative positional relationship in a given state. Depending on the orientation of each mechanism (e.g., reversing the overall structure vertically), the relative positional relationship can be reversed or rotated to any angle.

[0034] Furthermore, the dimensions of the components illustrated in this specification, such as width, length, and diameter, are not limited to those shown in the illustrations and may be appropriately changed. In this specification, various structures may be assigned ordinal numbers such as "first," "second," etc., but unless explicitly specified, these ordinal numbers do not define priority or order.

[0035] In this specification, "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 positive and negative electrodes may be collectively referred to as "electrodes." Furthermore, the positive and negative plates may be collectively referred to as "electrode plates."

[0036] In this manual, "battery" can be used in hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs). However, the use of "battery" is not limited to vehicle applications.

[0037] Figure 1 This is a front view of a secondary battery 1 according to an embodiment. Figure 2 as well as Figure 3 These represent observations from the direction of arrow II and the direction of arrow III, respectively. Figure 1 The diagram shows the state of secondary battery 1 (non-aqueous electrolyte secondary battery). Figure 4 yes Figure 1 The front cross-sectional view of the secondary battery 1 shown.

[0038] like Figures 1 to 4As shown, the secondary battery 1 includes a housing 100, an electrode body 200, an electrode terminal 300, and a current collector 400. The housing 100 includes a housing body 110, a sealing plate 120, and a sealing plate 130.

[0039] When constructing a battery module (battery pack) containing secondary batteries 1, multiple secondary batteries 1 are stacked in their thickness direction. The stacked secondary batteries 1 can be constrained in the stacking direction (Y direction) by a constraining member, or the battery pack can be directly supported on the side of the battery pack housing without using a constraining member.

[0040] The casing body 110 is composed of a cylindrical component. This results in a square secondary battery 1. The casing body 110 is made of metal. Specifically, the casing body 110 is made of aluminum, aluminum alloy, iron, or iron alloy, etc. The casing body 110 is preferably made of aluminum or aluminum alloy, and more preferably, for example, of A3003H, etc.

[0041] like Figure 1 As shown, sealing plates 120 and 130 are respectively provided at both ends of the main body of the shell. The main body of the shell 110 can be formed into a cylindrical shape by, for example, deep drawing. However, it is also possible to form a cylindrical shell 110 by bending a plate-like component. The corners of the "cylindrical" shape can also have an R-shape.

[0042] In this embodiment, the length of the housing body 110 in the width direction (X direction: third direction) of the secondary battery 1 is formed to be longer than the length in the thickness direction (Y direction: first direction) and height direction (Z direction: second direction) of the secondary battery 1.

[0043] The housing body 110 includes a pair of long sides and a pair of short sides. The pair of long sides and the pair of short sides are arranged to intersect each other (approximately orthogonal). The pair of long sides and the pair of short sides are connected to each other at their respective ends. The area of ​​each pair of long sides is larger than the area of ​​each pair of short sides.

[0044] like Figure 2 As shown, an opening 111 (first opening) is provided at one end of the housing body 110 in the X direction. The opening 111 is sealed by a sealing plate 120 (first sealing plate). The opening 111 and the sealing plate 120 have a generally rectangular shape with the Y direction being the short side and the Z direction being the long side. Furthermore, the generally rectangular shape includes shapes that are substantially rectangular, such as a rectangular shape or a shape with rounded corners. A negative terminal 310 is provided on the sealing plate 120. The position of the negative terminal 310 can be appropriately changed.

[0045] like Figure 3As shown, an opening 112 (second opening) is provided at the end of the housing body 110 on the opposite side in the X direction. Opening 112 is located at the end opposite to opening 111, and openings 111 and 112 are opposite to each other in the X direction. Opening 112 is sealed by a sealing plate 130 (second sealing plate). Opening 112 and sealing plate 130 have a generally rectangular shape with the Y direction as the shorter side and the Z direction as the longer side. A positive terminal 320 and a liquid injection hole 140 are provided on the sealing plate 130. The positions of the positive terminal 320 and the liquid injection hole 140 can be appropriately changed.

[0046] Sealing plates 120 and 130 are made of metal. Specifically, sealing plates 120 and 130 are made of aluminum, aluminum alloy, iron, or iron alloy.

[0047] The negative terminal 310 is electrically connected to the negative terminal of the electrode body 200. The negative terminal 310 is mounted on the sealing plate 120, i.e., the housing 100. The positive terminal 320 is electrically connected to the positive terminal of the electrode body 200. The positive terminal 320 is mounted on the sealing plate 130, i.e., the housing 100.

[0048] The negative terminal 310 is made of a conductive material (more specifically, a metal), such as copper or a copper alloy. A portion or layer of aluminum or an aluminum alloy may also be provided on the outer surface of the negative terminal 310.

[0049] The positive terminal 320 is made of a conductive material (more specifically, a metal), such as aluminum or an aluminum alloy.

[0050] The injection port 140 is sealed by a sealing component (not shown). Such sealing components can be, for example, blind rivets or other metal parts.

[0051] like Figure 4 As shown, the housing 100 houses the electrode body 200. The electrode body 200 is housed within the housing 100 with its long side parallel to the X direction. The electrode body 200 and the electrolyte are housed together within the housing 100. The electrode body 200 may also be a structure formed by overlapping multiple electrode bodies. The electrode body 200 includes a generally rectangular main body, a negative electrode tab group 210A, and a positive electrode tab group 220A.

[0052] The main body of the electrode body 200 is composed of a negative electrode plate 210 (negative electrode), a positive electrode plate 220 (positive electrode), and a diaphragm, as described later. The negative electrode tab group 210A and the positive electrode tab group 220A are formed to protrude from the main body of the electrode body 200 toward the sealing plate 120 or the sealing plate 130, respectively.

[0053] The current collector 400 includes a negative current collector 410 and a positive current collector 420. The electrode body 200 is electrically connected to the negative terminal 310 and the positive terminal 320 via the current collector 400.

[0054] The negative current collector 410 is disposed on the sealing plate 120 via a resin insulating component. The negative current collector 410 is electrically connected to the negative electrode tab assembly 210A and the negative terminal 310.

[0055] The positive current collector 420 is disposed on the sealing plate 130 via a resin insulating component. The positive current collector 420 is electrically connected to the positive electrode tab assembly 220A and the positive terminal 320.

[0056] Figure 5 This is a front view showing the negative electrode plate 210. (Example) Figure 5 As shown, a negative electrode tab 211, composed of a negative electrode core, is provided at one end of the negative electrode plate 210. When the negative electrode plates 210 are stacked, the negative electrode tabs 211 are stacked to form a negative electrode tab assembly 210A. In the portion corresponding to the main body of the electrode body 200, a negative electrode active material layer 212 is provided on the negative electrode plate 210.

[0057] Figure 6 This is a front view showing the positive electrode plate 220. For example... Figure 6 As shown, a positive electrode tab 221, composed of a positive electrode core, is provided at one end of the positive electrode plate 220. When the positive electrode plates 220 are stacked, the positive electrode tabs 221 are stacked to form a positive electrode tab assembly 220A. A positive electrode active material layer 222 is provided on the positive electrode plate 220 in the portion corresponding to the main body of the electrode body 200. A positive electrode protective layer 223 is provided at the root of the positive electrode tab 221. Alternatively, the positive electrode protective layer 223 may not be required.

[0058] In this embodiment, the electrode body 200 is a stacked electrode body consisting of multiple negative electrode plates 210 and multiple positive electrode plates 220 alternately stacked with a separator (not shown). However, the electrode body 200 may also be a wound electrode body with strips of negative electrode plates and positive electrode plates wound around it.

[0059] Figure 7 This is a diagram showing the structure of a battery module containing secondary battery 1. For example... Figure 7 As shown, the battery module includes multiple secondary batteries 1, a separator 2, a heat-conducting layer 3, and a temperature control component 4. The multiple secondary batteries 1 and the separator 2 are arranged alternately side by side along the Y direction.

[0060] The thermally conductive layer 3 is configured to be sandwiched between the secondary battery 1 and the temperature control component 4 in the Z direction. The thickness of the thermally conductive layer 3 is, for example, 1 mm or more, preferably 5 mm or less. The thermally conductive layer 3 is a layer made of a thermally conductive material such as polyurethane resin. The thermal conductivity of the thermally conductive material is, for example, 3 W / mK or more, preferably 5 W / mK or less.

[0061] The thermally conductive layer 3 can also be formed by applying an adhesive made of thermally conductive material to the bottom of the secondary battery 1, by attaching an adhesive tape made of thermally conductive material to the bottom of the secondary battery 1, or by placing a sheet made of thermally conductive material on the bottom of the secondary battery 1. The thermally conductive layer 3 does not necessarily need to be bonded to the casing 100 of the secondary battery 1.

[0062] The heat generated in the secondary battery 1 is transferred to the temperature control component 4 via the heat-conducting layer 3. The temperature control component 4 controls the temperature of the secondary battery 1 by promoting heat dissipation or cooling. The temperature control component 4 can be constructed of a plate-shaped metal component, for example, made of copper or aluminum. Alternatively, a passage can be provided inside the temperature control component 4 to allow a cooling medium to flow within the passage.

[0063] Figure 8 This is a cross-sectional view of the bottom of the casing body 110, which represents the first state of the secondary battery 1. Figure 9 This is a cross-sectional view of the bottom of the housing body 110, representing the second state of the secondary battery 1. The term "first state" here corresponds to the discharge state (e.g., SOC: 0%) or initial state of the secondary battery 1, and "second state" corresponds to the charge state (e.g., SOC: approximately 100%) or deterioration state of the secondary battery 1.

[0064] like Figure 8 , Figure 9 As shown, the housing body 110 includes a bottom surface S1 (first surface) and a pair of long side surfaces S2 and S3 (second and third surfaces). The electrode body 200 and the electrode body holder 500 are housed together within the housing body 110.

[0065] The bottom surface S1 extends in a direction orthogonal to the Z direction. The bottom surface S1 preferably has a width (dimension) of 30 mm or more (more preferably 35 mm or more, and even more preferably 40 mm or more) in the Y direction. The bottom surface S1 preferably has a width (dimension) of 300 mm or more (more preferably 350 mm or more, and even more preferably 400 mm or more) in the X direction.

[0066] At least a portion of the bottom surface S1 is in contact with the heat-conducting layer 3. The long side surfaces S2 and S3 extend in a direction orthogonal to the bottom surface S1. The long side surfaces S2 and S3 extend parallel to each other and are opposite to each other in the Y direction.

[0067] The bottom surface S1 has a thickness T1 (the thickness of the first plate), the long side surface S2 has a thickness T2 (the thickness of the second plate), and the long side surface S3 has a thickness T3 (the thickness of the third plate). Figure 8 , Figure 9 In the example shown, the thickness T1 of the bottom surface S1 is greater than the thicknesses T2 and T3 of the long sides S2 and S3, and the thicknesses T2 and T3 of the long sides S2 and S3 are approximately equal.

[0068] The thickness T1 of the bottom surface S1 is more preferably 1.3 times or more than the thicknesses T2 and T3 of the long sides S2 and S3, and even more preferably 1.5 times or more. The thickness T1 of the bottom surface S1 is preferably less than twice the thicknesses T2 and T3 of the long sides S2 and S3, more preferably less than 1.9 times, and even more preferably less than 1.8 times.

[0069] Specifically, the thickness T1 of the bottom surface S1 is preferably 3.3% or more of the width of the bottom surface S1 in the Y direction (including the total width of the R portion). The thicknesses T2 and T3 of the long sides S2 and S3 are preferably less than 2.0% of the width of the bottom surface S1 in the Y direction (including the total width of the R portion).

[0070] As an example, if the width of the bottom surface S1 in the Y direction is 30 mm, the thickness T1 of the bottom surface S1 is greater than 1.0 mm, and the thicknesses T2 and T3 of the long sides S2 and S3 are less than 0.7 mm.

[0071] However, the relationship between the thicknesses T1, T2, and T3 is not limited to the above range. For example, the thicknesses T1, T2, and T3 can also be equal to each other.

[0072] In addition, Figure 8 , Figure 9 In the example shown, a structure is constructed in which the bottom surface S1 and the long side surfaces S2 and S3, which have different thicknesses, are made of a single component. However, the scope of this technology is not limited to this. For example, it is also possible to make the outer part of the bottom surface S1 integrally formed with the long side surfaces S2 and S3, and to arrange a plate-shaped component as a separate component on its inner side, so that the thickness T1 (first plate thickness) of the bottom surface S1 is greater than the thickness T2 (second plate thickness) of the long side surface S2.

[0073] exist Figure 8 In the state shown (first state), the electrode body 200 has a thickness T201 (first thickness) in the Y direction. Figure 9In the state shown (the second state), the electrode body 200 has a thickness T202 (the second thickness) in the Y direction.

[0074] exist Figure 9 In the state shown, the electrode body 200 expands due to charging or deterioration. As a result, Figure 9 The thickness T202 of the electrode body 200 shown is greater than Figure 8 The thickness T201 of the electrode body 200 shown.

[0075] Specifically, the thickness T202 is preferably 1.5% or more of the width of the large bottom surface S1 of the thickness T201 in the Y direction (including the total width of the R portion). The thickness T202 is preferably less than 10% (more preferably less than 5%) of the width of the large bottom surface S1 of the thickness T201 in the Y direction.

[0076] As an example, if the width of the bottom surface S1 in the Y direction is 30 mm, the expansion of the fully charged electrode body 200 relative to the discharged state is 0.5 mm.

[0077] A corner portion C1 (first corner portion) is provided on the outer surface of the housing body 110 located between the bottom surface S1 and the long side surface S2, and a corner portion C2 (second corner portion) is provided on the outer surface of the housing body 110 located between the bottom surface S1 and the long side surface S3.

[0078] Corner portions C1 and C2 have an R-shape. Corner portion C1 has a radius of curvature R1 (first radius of curvature), and corner portion C2 has a radius of curvature R2 (second radius of curvature). In this embodiment, the radii of curvature R1 and R2 are 0.5 mm or less. The radii of curvature R1 and R2 are preferably 0.2% or more (more preferably 0.25% or more, and even more preferably 0.3% or more) of the width of the bottom surface S1 in the Y direction (including the total width of the R portion).

[0079] The inner surface of the bottom surface S1 is separated from the electrode body 200 by a distance H (separation distance) in the Z direction. The distance H is preferably at least 30% of the thickness T1 of the bottom surface S1 of the housing body 110. However, the separation distance between the bottom surface S1 and the electrode body 200 is not limited to the above range.

[0080] in addition, Figure 8 , Figure 9 The distance H shown (the separation distance in the Z direction between the inner surface of the bottom surface S1 and the electrode body 200) is as described later. Figure 13 As shown, H corresponds to the distance H between the inner surface of the bottom surface S1 and the lower surface of the diaphragm 230.

[0081] Figure 10This is a cross-sectional view showing the bottom of the casing body 110A of the secondary battery involved in the comparative example. Figure 10 The image shows the electrode body 200A expanding to a thickness of T202A (state 2). The heat generated in the secondary battery is transferred to the temperature control component 4A via the thermally conductive layer 3A.

[0082] exist Figure 10 In the comparative example shown, the thicknesses of the bottom surface S1A and the pair of long side surfaces S2A and S3A are approximately equal. Figure 10 In the comparative example shown, the thickness of the bottom surface S1A is only the same as that of the long sides S2A and S3A. Therefore, if compared with... Figure 8 , Figure 9 Compared to the secondary battery 1 shown, the bottom surface S1A is more prone to deformation as the electrode body 200A expands.

[0083] In addition, Figure 10 In the comparative example shown, the radii of curvature R1A and R2A of the corners C1A and C2A located at both ends of the bottom surface S1A are compared with those of the corners C1A and C2A located at both ends of the bottom surface S1A. Figure 8 , Figure 9 The radii of curvature R1 and R2 shown are large (e.g., to the extent of 1 mm). Therefore, the contact area between the bottom surface S1A of the housing body 110A and the heat-conducting layer 3A is relatively smaller.

[0084] As a result of the above, Figure 10 In the comparative examples shown, with Figure 8 , Figure 9 Compared to the secondary battery 1 shown, it is easier for a gap to be generated between the bottom surface S1A of the housing body 110A and the heat-conducting layer 3A.

[0085] In contrast, Figure 8 , Figure 9 In the secondary battery 1 shown, by making the thickness T1 of the bottom surface S1 greater than the thicknesses T2 and T3 of the long sides S2 and S3, the following is achieved: Figure 8 , Figure 9 As shown, it can suppress the deformation of the bottom surface S1, and even when the electrode body 200 expands, it can suppress the formation of a gap between the bottom surface S1 of the housing body 110 and the heat-conducting layer 3.

[0086] In addition, Figure 8 , Figure 9 In the secondary battery 1 shown, by making the radii of curvature R1 and R2 of the corners C1 and C2 at both ends of the bottom surface S1 less than 0.5 mm, the flat portion of the bottom surface S1 can be formed to be relatively large, thereby increasing the contact area between the bottom surface S1 and the heat-conducting layer 3.

[0087] As described above, in the secondary battery 1 according to this embodiment, the occurrence of gaps between the bottom surface S1 of the housing body 110 and the heat-conducting layer 3 can be suppressed, and the contact area between the bottom surface S1 and the heat-conducting layer 3 can be relatively increased. As a result, efficient temperature control can be achieved in the secondary battery module.

[0088] Next, use Figure 11 The method for calculating the thickness of electrode body 200 is explained. Figure 8 , Figure 9 The thicknesses T201 and T202 shown are defined pressing areas 100A (e.g., an area of ​​10 cm² centered on the geometric center) of the housing 100, which includes a pair of long side surfaces, are pressed along the Y direction with a specified load (e.g., 180 N). 2 The value obtained by subtracting the thickness of the components other than the electrode body 200 (e.g., the thickness of the housing 100 × 2 + the electrode body holder 500 × 2 = 0.65 mm × 2 + 0.15 mm × 2) from the thickness (Y direction dimension) of the housing 100 when the circular area is defined.

[0089] Figure 12 This diagram shows the configuration of the heat-conducting layer 3 on the bottom surface S1 of the housing 100 and the gas discharge valve 150. (See diagram below.) Figure 12 As shown, a gas discharge valve 150 is provided on the bottom surface S1 of the housing 100. The gas discharge valve 150 will rupture preferentially when the pressure inside the housing 100 reaches a predetermined value, thereby discharging the gas inside the housing 100 to the outside.

[0090] The bottom surface S1 has a region in contact with the heat-conducting layer 3 (region 1) and a region without the heat-conducting layer 3 (region 2). The gas discharge valve 150 is located in the region without the heat-conducting layer 3.

[0091] The extent of the heat-conducting layer 3 can be appropriately varied, but it is preferably positioned at the center of the bottom surface S1 in the Y direction. The heat-conducting layer 3 preferably has an area of ​​at least 20% of the flat area of ​​the bottom surface S1. Alternatively, if the gas exhaust valve 150 is not located on the bottom surface S1, the heat-conducting layer 3 may be provided entirely on the flat area of ​​the bottom surface S1.

[0092] Figure 13 This is a cross-sectional view showing the structure of the electrode body 200 and the configuration of the gas discharge valve 150. Figure 13 For ease of illustration, the diaphragm 230 is shown only on the outer side of the negative electrode plate 210 and the positive electrode plate 220, but the diaphragm 230 is also disposed between the negative electrode plate 210 and the positive electrode plate 220. Figure 13 The number of layers of the negative electrode 210 and the positive electrode 220 shown is an example and can be changed appropriately.

[0093] like Figure 13 As shown, the end of the positive electrode plate 220 located near the bottom surface S1 (bottom side of the attached figure) is separated from the inner surface of the bottom surface S1 by a distance A (first distance) in the Z direction. Furthermore, at the boundary portion (corners C1, C2) between the positive electrode plate and the bottom surface S1, the inner surface of the long side surface S2 is separated from the inner surface of the long side surface S3 by a distance B (second distance) in the Y direction.

[0094] Here, it is preferable that distance A is greater than distance B by more than 20% (more preferably more than 30%, and even more preferably more than 50%).

[0095] By making the distance from the bottom surface S1 of the housing 100 to the electrode body 200 larger, deformation of the bottom surface S1 when the electrode body 200 expands can be suppressed, and the formation of gaps between the bottom surface S1 and the heat-conducting layer 3 can be prevented. As a result, efficient temperature control can be achieved in the secondary battery module.

[0096] The inventors of this technology have confirmed that by setting distance A to 20% of distance B, compared to setting distance A to 7% of distance B, the deformation of the bottom surface S1 of the housing 100 can be reduced to one-third. Furthermore, the inventors of this technology have confirmed that by setting distance A to 60% of distance B, compared to setting distance A to 20% of distance B, the deformation of the bottom surface S1 of the housing 100 can be reduced to one-third.

[0097] As the secondary battery 1 is charged and discharged, gas is generated inside the casing 100, and the internal pressure of the casing 100 increases, thereby, for example, Figure 13 As shown, the top 160 of the housing 100 deforms in an outward expansion manner.

[0098] exist Figure 13 In the secondary battery 1 shown, by increasing the distance from the bottom surface S1 of the housing 100 to the electrode body 200, gas is more easily trapped at the bottom of the housing 100. Therefore, when the internal pressure of the housing 100 rises, the gas discharge valve 150 provided at the bottom surface S1 operates stably, suppressing excessive rises in the internal pressure of the housing 100. As a result, it is possible to prevent gas or contents from being ejected from unexpected parts of the housing 100.

[0099] Furthermore, in the secondary battery 1 according to this embodiment, as described above, deformation of the bottom surface S1 of the casing 100 can be suppressed. Therefore, the gas discharge valve 150 provided on the bottom surface S1 can operate stably.

[0100] Figure 13The example shown is an electrode body 200 of a stacked electrode body. Even if it is a wound electrode body, it can be used with... Figure 13 Following the same logic, in this case, the distance A between the lower end of the positive electrode of the preferred wound electrode body (the part closest to the bottom surface S1) and the inner surface of the bottom surface S1 is greater than the distance B between the inner surface of the long side surface S2 and the inner surface of the long side surface S3 by more than 20% (more preferably more than 30%, and even more preferably more than 50%).

[0101] exist Figure 13 In the example, the lower ends of the multiple positive electrode plates 220 are all at the same height (position in the Z direction), but the scope of this technology is not limited to this. For example, some of the positive electrode plates 220 may have different lower end heights. When the lower ends of the multiple positive electrode plates 220 are at different heights, the average value of the distances between the lower ends of the multiple positive electrode plates 220 and the inner surface of the bottom surface S1 is set as the distance A (first distance) between the end of the positive electrode plate 220 and the inner surface of the bottom surface S1.

[0102] Figure 14 This is a front sectional view of the battery module involved in the modified example. For example... Figure 14 As shown, a notch 201 may be provided in a part of the electrode body 200, so that the separation distance from the bottom surface S1 of the housing 100 to the lower end of the positive electrode plate 220 varies in the X direction.

[0103] exist Figure 14 In the example shown, in the region (first region) where the bottom surface S1 of the housing 100 contacts the heat-conducting layer 3, the inner surface of the bottom surface S1 is separated from the end of the positive electrode plate 220 in the Z direction by a distance A (first distance). In the region (second region) where the heat-conducting layer 3 is not disposed, the inner surface of the bottom surface S1 is separated from the end of the positive electrode plate 220 in the Z direction by a distance C (third distance) smaller than the distance A. For example, if the width of the bottom surface S1 in the Y direction is 30 mm, it is preferable that the distance A is 6 mm or more, and the distance C is preferably less than 2 mm.

[0104] according to Figure 14 In the modified example shown, in the region where the bottom surface S1 of the housing 100 contacts the heat-conducting layer 3, the electrode body 200 is moved away from the bottom surface S1, thereby suppressing deformation of the bottom surface S1 caused by the expansion of the electrode body 200. On the other hand, in the region where the heat-conducting layer 3 is not disposed, the electrode body 200 is positioned close to the bottom surface S1, thereby expanding the area of ​​the electrode body 200. As a result, efficient temperature control and increased energy density can be achieved in the secondary battery module.

[0105] While embodiments of the present invention have been described, it should be understood that the embodiments disclosed herein are illustrative in all respects and not limiting. The scope of the invention is shown by the technical solutions and is intended to include all modifications within the meaning and scope of equivalents to the technical solutions.

Claims

1. A secondary battery module, characterized in that, have: Multiple batteries, each comprising an electrode body and a square housing containing the electrode body, are arranged along a first direction; A temperature control component that controls the temperature of the plurality of batteries; as well as A thermally conductive layer, which is sandwiched between the plurality of batteries and the temperature control component in a second direction orthogonal to the first direction, The housing has: a first surface having a first plate thickness, extending in a direction orthogonal to the second direction, and at least a portion therein contacting the heat-conducting layer; a second surface having a second plate thickness, extending in a direction orthogonal to the first surface; a third surface extending parallel to the second surface and facing the second surface in the first direction; and a first corner portion disposed on the outer surface of the housing between the first surface and the second surface. And the second corner portion, which is disposed on the outer surface of the housing between the first surface and the third surface. In a first state of the plurality of batteries, the electrode body has a first thickness in a first direction; in a second state of the plurality of batteries, the electrode body has a second thickness in the first direction, wherein the second thickness is greater than the first thickness by at least 1.5% of the dimension of the first surface in the first direction. The thickness of the first plate of the housing is greater than the thickness of the second plate. The first corner of the housing has a first radius of curvature, and the second corner has a second radius of curvature, wherein the first radius of curvature and the second radius of curvature are both less than 0.5 mm.

2. The secondary battery module according to claim 1, characterized in that, The thickness of the first plate is less than twice the thickness of the second plate.

3. The secondary battery module according to claim 1 or 2, characterized in that, The inner surface of the first surface is separated from the electrode body in the second direction by more than 30% of the thickness of the first plate.

4. The secondary battery module according to claim 1 or 2, characterized in that, The housing includes: a housing body, which is cylindrical, includes the first surface to the third surface, and has a first opening and a second opening at both ends in a third direction orthogonal to the first direction and the second direction; and a first sealing plate and a second sealing plate, which respectively seal the first opening and the second opening.

5. The secondary battery module according to claim 4, characterized in that, The first surface of the housing has a dimension of 300 mm or more in the third direction.

6. The secondary battery module according to claim 1 or 2, characterized in that, The electrode body is a stacked electrode body formed by stacking positive and negative electrodes through a diaphragm.

7. The secondary battery module according to claim 1 or 2, characterized in that, The thermally conductive layer is disposed at the center of the first surface in the first direction.

8. The secondary battery module according to claim 1 or 2, characterized in that, The first radius of curvature and the second radius of curvature are both greater than 0.2% of the dimension of the first surface in the first direction.

9. The secondary battery module according to claim 1 or 2, characterized in that, A gas discharge valve is provided on the first side of the housing.

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