Batteries and battery modules

Abstract

To provide a battery and a battery module which can downsize a package and can improve space efficiency when are stored.SOLUTION: A battery cell 20 includes: an electrode body 40 in which an electrode and a separator are alternately deposited; a battery case 22 for storing the electrode body 40 inside; and an electrode lead 26 with one end connected to the electrode body 40 in the battery case 22 and with the other end protruding from an edge part of the battery case 22 in a width direction and folded back to the battery case 22 side.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a battery and a battery module.

Background Art

[0002] The secondary battery disclosed in Patent Document 1 below includes a battery case that houses an electrode assembly inside, and an electrode lead whose one end is connected to the electrode assembly inside the battery case. The other end of this electrode lead protrudes outside the battery case.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the secondary battery disclosed in Patent Document 1 above, since the other end of the electrode lead protrudes outside the battery case, the accommodation space becomes large in order to accommodate the other end of the electrode lead.

[0005] In consideration of the above facts, an object of the present invention is to obtain a battery and a battery module that can reduce the size of the package and improve the space efficiency during accommodation.

Means for Solving the Problems

[0006] The battery according to the first aspect includes an electrode body in which electrodes and separators are alternately laminated, a battery case that houses the electrode body inside, and an electrode lead whose one end is connected to the electrode body inside the battery case and whose other end protrudes from an end in the width direction of the battery case and is folded back toward the battery case side.

[0007] The first embodiment of the battery comprises an electrode body in which electrodes and separators are alternately stacked, a battery case that houses the electrode body, and an electrode lead, one end of which is connected to the electrode body inside the battery case. Here, the other end of the electrode lead protrudes from the widthwise end of the battery case and is folded back towards the battery case. This makes the package smaller in the widthwise direction of the battery case and improves space efficiency during housing.

[0008] In the second embodiment of the battery, the other end of the electrode lead has a folded portion that is folded back toward the battery case, and an extended portion that extends upward from the folded portion toward the battery case and protrudes from the upper end of the battery case.

[0009] In the second embodiment of the battery, the other end of the electrode lead has a folded portion that is folded back toward the battery case, and an extended portion that extends from the folded portion toward the upper side of the battery case and protrudes from the upper end of the battery case. This allows access from the upper side of the battery case to connect the electrode lead to the busbar, etc., making it possible to connect the electrode lead after the battery case has been placed in a predetermined storage space. Therefore, it offers excellent workability and increased versatility in integration into the manufacturing process.

[0010] In the third embodiment of the battery, in the first or second embodiment, the battery case has a recessed housing portion formed on at least one side surface in the thickness direction of the battery case, in which the electrode body is housed, and an outer end portion provided on the outside of the housing portion, and the other end of the electrode lead is folded back toward the battery case side, and the overlap width in the thickness direction with respect to the battery case is narrower than the width of the outer end portion.

[0011] In the third embodiment of the battery, the battery case has a recessed housing portion on at least one side in the thickness direction of the battery case into which the electrode body is housed, and an outer end portion provided outside the housing portion. Here, the other end of the electrode lead is folded back towards the battery case side, and the overlap width in the thickness direction of the battery case is narrower than the width of the outer end portion. Therefore, even if the other end of the electrode lead is folded back toward the embossed side, the electrode lead can be housed without interfering with the housing portion. As a result, for example, the same design can be applied to both single-cup embossed and double-cup embossed battery case structures, thereby increasing versatility.

[0012] The fourth embodiment of the battery is, in the first or second embodiment, the battery case has a recessed housing portion formed on at least one side surface in the thickness direction of the battery case, in which the electrode body is housed, and an outer end portion provided on the outside of the housing portion, and the other end of the electrode lead is folded back toward the battery case side, and the overlap width in the thickness direction of the battery case is wider than the width of the outer end portion.

[0013] In the fourth embodiment of the battery, the battery case has a recessed housing portion on at least one side in the thickness direction of the battery case in which the electrode body is housed, and an outer end portion provided on the outside of the housing portion. Here, the other end of the electrode lead is folded back towards the battery case side, and the overlap width that overlaps with the battery case in the thickness direction is wider than the width of the outer end portion. For example, when multiple batteries are stacked and housed in a predetermined housing space along the thickness direction of the battery case, the other end of the electrode lead is sandwiched between adjacent battery cases. This makes it possible to create a gap in the center of the width direction of the battery case corresponding to the thickness of the electrode lead, and the expansion and contraction of the battery during charging and discharging can be absorbed by this gap.

[0014] Furthermore, when multiple batteries are stacked and housed in a predetermined storage space along the thickness direction of the battery case, a predetermined restraining pressure is applied to each battery case along the stacking direction (thickness direction). At this time, the other end of the electrode lead is sandwiched between adjacent battery cases, so that the restraining pressure at the ends in the width direction of the battery case is higher than at the center. As a result, in the case of liquid-based batteries, the electrolyte can be evenly distributed to the center of the battery case, and unevenness in the reaction of the electrode body due to uneven distribution of the electrolyte within the battery case can be suppressed.

[0015] A fifth embodiment of the battery module is a battery module in which the batteries of the first embodiment are housed in a module case, wherein a plurality of the batteries are stacked inside the module case along the thickness direction of the battery case, and the other end of the electrode lead is positioned between adjacent battery cases.

[0016] In the fifth battery module, the other end of the electrode lead is folded back towards the battery case, resulting in a battery with a smaller package in the width direction of the battery case. Multiple batteries are stacked inside the module case along the thickness direction of the battery case. As a result, the other end of the electrode lead is positioned between adjacent battery cases, which allows the module case to be made smaller in the width direction of the battery case, improving space efficiency when housing the battery module. [Effects of the Invention]

[0017] As described above, the battery and battery module according to the present invention make it possible to reduce the size of the package and improve space efficiency during housing. [Brief explanation of the drawing]

[0018] [Figure 1] This is a schematic plan view showing the main parts of a vehicle to which the battery pack according to the embodiment is applied. [Figure 2] This is a schematic perspective view of the battery module according to the embodiment. [Figure 3]It is a plan view of the battery module according to the embodiment with the upper lid of the module case removed. [Figure 4] It is a schematic view of the battery cells housed in the battery module as viewed from the thickness direction. [Figure 5] It is a diagram for explaining a part of the manufacturing process of the battery module. (A) shows the process of folding back the electrode leads of the battery cells, (B) shows the process of inserting the electrode leads into the through holes of the bus bar, and (C) shows the process of connecting the electrode leads to the bus bar. [Figure 6] It is a schematic plan view showing a partially enlarged state of a plurality of battery cells housed in the module case. [Figure 7] It is a diagram for explaining a modified example of the battery cell, and it is a schematic plan view showing a partially enlarged state of a plurality of battery cells housed in the module case.

Mode for Carrying Out the Invention

[0019] Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 6.

[0020] (Overall Configuration of Vehicle 100) FIG. 1 is a schematic plan view showing a main part of a vehicle 100 to which a battery pack 10 according to the embodiment is applied. As shown in FIG. 1, the vehicle 100 is a battery electric vehicle (BEV) in which the battery pack 10 is mounted under the floor. In addition, the arrows UP, FR, and LH in each figure indicate the upper side in the vehicle up-down direction, the front side in the vehicle front-rear direction, and the left side in the vehicle width direction, respectively. When explaining using the front-rear, left-right, and up-down directions of the vehicle, unless otherwise specified, the front and rear in the vehicle front-rear direction, the left and right in the vehicle width direction, and the up and down in the vehicle up-down direction are shown.

[0021] In this embodiment, the vehicle 100, as an example, has a DC / DC converter 102, an electric compressor 104, and a PTC (Positive Temperature Coefficient) heater 106 positioned in front of the battery pack 10. The motor 108, gearbox 110, inverter 112, and charger 114 are positioned behind the battery pack 10.

[0022] The DC current output from the battery pack 10 is voltage-adjusted by the DC / DC converter 102 and then supplied to the electric compressor 104, PTC heater 106, inverter 112, etc. Power is also supplied to the motor 108 via the inverter 112, causing the rear wheels to rotate and the vehicle 100 to move.

[0023] A charging port 116 is provided on the right side of the rear of the vehicle 100. By connecting a charging plug from an external charging device (not shown) to the charging port 116, power can be stored in the battery pack 10 via the onboard charger 114.

[0024] The arrangement and structure of the components constituting the vehicle 100 are not limited to the configuration described above. For example, it may be applied to a hybrid vehicle (HV) or a plug-in hybrid electric vehicle (PHEV) equipped with an engine. In this embodiment, the motor 108 is mounted at the rear of the vehicle and it is a rear-wheel drive vehicle, but it is not limited to this, and it may be a front-wheel drive vehicle with the motor 108 mounted at the front of the vehicle, or a pair of motors 108 may be mounted at the front and rear of the vehicle. Furthermore, it may be a vehicle equipped with in-wheel motors for each wheel.

[0025] Here, the battery pack 10 is composed of multiple battery modules 11. In this embodiment, as an example, 10 battery modules 11 are provided. Specifically, 5 battery modules 11 are arranged in the longitudinal direction of the vehicle on the right side of the vehicle 100, and 5 battery modules 11 are arranged in the longitudinal direction of the vehicle on the left side of the vehicle 100. Furthermore, each battery module 11 is electrically connected.

[0026] Figure 2 is a schematic perspective view of the battery module 11. As shown in Figure 2, the battery module 11 includes a module case 16 that forms the outer shell. The module case 16 is formed in a substantially rectangular parallelepiped shape with the vehicle width direction as its longitudinal direction. The module case 16 is also formed of an aluminum alloy. For example, the module case 16 is formed by joining aluminum die-cast parts to both ends of an aluminum alloy extruded material by laser welding or the like.

[0027] A pair of voltage terminals 12 and a connector 14 are provided at both ends of the battery module 11 in the vehicle width direction. A flexible printed circuit board 21, which will be described later, is connected to the connector 14. In addition, bus bars 30 (see Figure 4) are welded to both ends of the battery module 11 in the vehicle width direction.

[0028] The length MW of the battery module 11 in the vehicle width direction is, for example, 350 mm to 600 mm, the length ML in the vehicle longitudinal direction is, for example, 150 mm to 250 mm, and the height MH in the vehicle vertical direction is, for example, 80 mm to 110 mm.

[0029] Figure 3 is a plan view of the battery module 11 with the top cover removed. As shown in Figure 3, battery cells 20 are housed inside the module case 16. As an example, multiple battery cells 20 are housed inside the module case 16 in an arranged (stacked) state. In this embodiment, 24 battery cells 20 are arranged in the front-rear direction of the vehicle and bonded to each other.

[0030] For the sake of clarity, in Figures 3 to 6, the direction indicated by arrow W represents the width direction of the battery cell 20, the direction indicated by arrow H represents the height direction (up and down direction) of the battery cell 20, and the direction indicated by arrow D represents the thickness direction of the battery cell 20. The width direction of the battery case 22, as described later, coincides with the width direction W of the battery cell 20. The height direction of the battery case 22 coincides with the height direction H of the battery cell 20. The thickness direction of the battery case 22 coincides with the thickness direction D of the battery cell 20.

[0031] A flexible printed circuit board (FPC) 21 is placed on top of the battery cell 20. The flexible printed circuit board 21 is formed in a strip shape with the vehicle width direction as its longitudinal direction, and thermistors 23 are provided at both ends of the flexible printed circuit board 21. The thermistors 23 are not bonded to the battery cell 20, but are pressed toward the battery cell 20 by the upper cover of the battery module 11.

[0032] Furthermore, one or more cushioning materials (not shown) are housed inside the module case 16. For example, the cushioning material is a thin, elastically deformable plate-like member, and is placed between adjacent battery cells 20 with the arrangement direction of the battery cells 20 as the thickness direction. In this embodiment, as an example, cushioning material is placed at both ends in the longitudinal direction and in the longitudinal center of the module case 16.

[0033] Figure 4 is a schematic diagram of a battery cell 20 housed in a battery module 11, viewed from the thickness direction D. As shown in Figure 4, the battery cell 20 is formed in the shape of a long rectangular plate with the width direction W as the longitudinal direction, and is equipped with a battery case 22 that forms the outer shell. An electrode body 40 is housed inside the battery case 22. The electrode body 40 is constructed by laminating a positive electrode, a negative electrode, and a separator. In this embodiment, the battery case 22 is made of laminate film, and the electrode body 40 is sealed with laminate film.

[0034] The battery case 22 is embossed on at least one side in the thickness direction. The embossing creates a recessed housing portion 221 on the side surface in which the electrode body 40 is housed, and an outer end portion 223 provided outside the housing portion 221. The battery case 22 can employ either a single-cup embossed structure with one embossed area or a double-cup embossed structure with two embossed areas, but in this embodiment, it is a single-cup embossed structure with a recess depth of approximately 8 mm to 10 mm. Therefore, one first side surface 22A in the thickness direction of the battery case 22 is an embossed surface, and the other second side surface 22B (see Figure 6) in the thickness direction is a non-embossed surface.

[0035] The upper end of the battery case 22 in the width direction is bent, the corners are chamfered, and it has a roughly trapezoidal shape. In addition, the upper end of the battery case 22 is bent, and fixing tape 24 is wrapped around the upper end of the battery case 22 along the width direction.

[0036] Here, the battery cell 20 is equipped with electrode leads 26 that protrude from the end of the battery case 22. The electrode leads 26 are provided at both ends in the width direction of the battery cell. In this embodiment, as an example, the electrode leads 26 are provided at a position offset below the center of the height direction H of the battery cell 20. One end of the electrode lead 26 is connected to the electrode body 40 inside the battery case 22. The other end of the electrode lead 26 protrudes from the width direction end of the battery case 22 and is folded back towards the battery case 22.

[0037] The other end of the electrode lead 26 has a folded portion 261 that is folded back toward the battery case 22, and an extended portion 262 that extends from the folded portion 261 toward the upper side of the battery case 22 and protrudes from the upper end of the battery case 22. The electrode lead 26 has a roughly L-shape due to the folded portion 261 and the extended portion 262. The tip of the extended portion 262 is joined to the busbar 30 by laser welding or the like. The electrode lead 26 is connected to the external wiring of the battery module 11 via the busbar 30.

[0038] The length CW1 of the battery cell 20 in the vehicle width direction is, for example, 530 mm to 600 mm, the length CW2 of the area where the electrode body is housed is, for example, 500 mm to 520 mm, and the height CH of the battery cell 20 is, for example, 80 mm to 110 mm. The thickness of the battery cell 20 is 7.0 mm to 9.0 mm, and the height TH of the folded portion 261 of the electrode lead (terminal) 26 is 40 mm to 50 mm.

[0039] Furthermore, in this embodiment, the other end of the electrode lead 26 is folded back towards the battery case 22, and the overlap width TW that overlaps with the battery case 22 in the thickness direction is set to be smaller than the width CW3 of the outer end 223 of the embossed first side surface 22A.

[0040] Figures 5(A) to 5(C) illustrate a part of the manufacturing process of the battery module 11, showing the folding process of the electrode leads 26 and the joining process in which they are joined to the busbar 30.

[0041] As shown in Figure 5(A), the other end of the electrode lead 26 is folded back along a fold line L1 that extends along the widthwise edge of the battery case 22, thereby forming a folded portion 261 at the bottom in the height direction H.

[0042] Next, as shown in Figure 5(B), the bus bar 30 is positioned on the upper side of the battery case 22, and the tip of the extension 262 is inserted into the through hole 32 formed through the bus bar 30.

[0043] Next, as shown in Figure 5(C), the tip of the extension 262 that protrudes above the busbar 30 through the through hole 32 is bent along the fold line L2 and welded to the upper surface of the busbar 30 using a welding machine 200 or the like. This joins the electrode lead 26 and the busbar 30.

[0044] The steps shown in Figures 5(B) and 5(C) may be performed before the step of housing the battery cells 20 in the module case 16, or after the step of housing the battery cells 20 in the module case 16.

[0045] Figure 6 is a schematic plan view showing a partially enlarged view of multiple battery cells housed in a module case 16. As shown in Figure 6, inside the module case 16, multiple battery cells 20 are stacked along the thickness direction of the battery case 22, and the folded portion 261 and extended portion 262 of the electrode lead 26 are positioned between adjacent battery cases 22. For the sake of explanation, Figure 6 shows spacing between the battery cells 20, but in reality, the stacked battery cells 20 are in contact either via a buffer material or directly, and are constrained from one another with a predetermined restraining pressure applied along the stacking direction (thickness direction D).

[0046] In this embodiment, the other end of the electrode lead 26 is folded back towards the battery case 22, thereby reducing the size of the battery cell 20 package in the width direction W, and thus improving the efficiency of the storage space within the module case 16.

[0047] Furthermore, since the overlap width TW between the other end of the electrode lead 26 and the battery case 22 is narrower than the width CW3 of the outer end 223 of the battery case 22, a gap is formed between the electrode lead 26 and the housing portion 221 of the battery case 22.

[0048] In the configuration shown in Figure 6, the electrode lead 26 is folded back towards the first side surface 22A of the battery case 22, or is not limited to this configuration. The electrode lead 26 may also be folded back towards the second side surface 22B.

[0049] (Mechanism of action and effect) As described above, the battery cell 20 according to this embodiment includes an electrode body 40 in which electrodes and separators are alternately stacked, a battery case 22 that houses the electrode body 40, and an electrode lead 26 inside the battery case 22, one end of which is connected to the electrode body 40. Here, the other end of the electrode lead 26 protrudes from the widthwise end of the battery case 22 and is folded back towards the battery case 22. This makes the package smaller in the widthwise direction of the battery case 22 and improves space efficiency during housing.

[0050] Furthermore, in this embodiment, the other end of the electrode lead 26 has a folded portion 261 that is folded back toward the battery case 22, and an extended portion 262 that extends from the folded portion 261 toward the upper side of the battery case 22 and protrudes from the upper end of the battery case 22. This allows access from the upper side of the battery case 22 to connect the electrode lead 26 to the busbar 30, making it possible to connect the electrode lead 26 to the busbar 30 after housing the battery case 22 inside the module case 16. Therefore, it offers excellent workability and increased versatility in integration into the manufacturing process.

[0051] Furthermore, in this embodiment, the battery case 22 has an embossed surface on one of its first side surfaces 22A in the thickness direction, forming a concave housing portion 221 into which the electrode body 40 is housed, and an outer end portion 223 provided outside the housing portion 221. Here, the other end of the electrode lead 26 is folded back towards the battery case 22, and the overlap width TW that overlaps the battery case 22 in the thickness direction is narrower than the width CW3 of the outer end portion 223. Therefore, as shown in Figure 6, even when the other end of the electrode lead 26 is folded back toward the embossed first side surface 22A, the other end of the electrode lead 26 can be housed without interfering with the housing portion 221. As a result, the same design can be applied to both single-cup embossed and double-cup embossed battery case 22 structures, increasing versatility.

[0052] Furthermore, as in the embodiment, the battery module 11 has multiple battery cells 20 stacked inside the module case 16 along the thickness direction of the battery case 22, with the other end of the electrode lead 26 positioned between adjacent battery cases 22. This makes it possible to miniaturize the module case 16 in the width direction of the battery case 22, thereby improving space efficiency when housing the battery module 11 in the battery pack 10.

[0053] (Variations of battery cells) Next, with reference to Figure 7, a modified battery cell 60 according to the above embodiment will be described. Note that components similar to those in the above embodiment are denoted by the same reference numerals, and detailed descriptions are omitted.

[0054] Figure 7 is a schematic plan view showing a partially enlarged view of multiple battery cells 60 housed in a module case 16. As shown in Figure 7, the battery case 22 that constitutes the outer shell of the battery cell 60 has an embossed surface on one of its first sides 22A in the thickness direction. This creates a concave housing portion 221 and an outer end portion 223 provided outside the housing portion 221 on the first side portion 22A. The other end of the electrode lead 26 protruding from the widthwise end of the battery case 22 is folded back towards the battery case 22, similar to the embodiment described above.

[0055] Note that in Figure 7, for the sake of explanation, a gap is shown between the battery cells 60. However, in reality, the stacked battery cells 60 are in contact with each other either through a buffer material or directly, and are constrained together with a predetermined restraining pressure applied along the stacking direction (thickness direction D).

[0056] In this modified example, the other end of the electrode lead 26 is folded back towards the battery case 22, and the overlap width TW that overlaps the battery case 22 in the thickness direction is configured to be wider than the width of the outer end 223. As a result, when multiple battery cells 20 are stacked and housed in the storage space within the module case 16 along the thickness direction of the battery case 22, the other end of the electrode lead 26 is sandwiched between the sides of adjacent battery cases 22. This allows a gap equivalent to the thickness of the electrode lead 26 to be created in the center of the battery case 22 in the width direction, and the expansion and contraction of the battery cells 20 during charging and discharging can be absorbed by this gap.

[0057] Furthermore, when multiple battery cells 20 are stacked and housed in the storage space within the module case 16 along the thickness direction of the battery case 22, a predetermined restraining pressure is applied to the battery case 22 of each battery cell 20 along the stacking direction (thickness direction D). At this time, the other end of the electrode lead 26 is sandwiched between adjacent battery cases 22, so that the restraining pressure at the widthwise end of the battery case 22 is higher than at the center. As a result, in the case of an electrolyte-based battery, the electrolyte can be distributed well to the center of the battery case 22, and unevenness in the reaction of the electrode body 40 due to uneven distribution of the electrolyte within the battery case 22 can be suppressed.

[0058] In the configuration shown in Figure 7, the other end of the electrode lead 26 is folded back to the second side surface 22B, which has a non-embossed surface, but the configuration is not limited to this. The other end of the electrode lead 26 may also be folded back to the first side surface 22A, which has an embossed surface. In this case as well, the other end of the electrode lead 26 is sandwiched between the sides of the adjacent battery case 22.

[0059] Although one embodiment and one modification have been described above, the present invention can be implemented with various modifications without departing from its spirit. Of course, the scope of the present invention is not limited to the above-described embodiment.

[0060] For example, in the above embodiment and modified examples, the extension portion 262 is integrally formed with the folded portion 261, but the invention is not limited thereto. The extension portion 262 may be formed separately from the folded portion 261 and joined to the folded portion 261 by welding or the like.

[0061] Furthermore, in the above embodiment and its modified form, the other end of the electrode lead 26 protruding from one battery case 22 is folded back and arranged between adjacent battery cases 22 within the module case 16, but the configuration is not limited to this. In order to arrange the electrode leads of adjacent battery cells 20 closer together, the other end of the electrode lead 26 protruding from each battery case may be folded back and arranged between adjacent battery cases. [Explanation of symbols]

[0062] 11 Battery Modules 16 Module Cases 20 battery cells (batteries) 22 Battery Case 22A First side (one side in the thickness direction of the battery case) 221 Storage Unit 223 Outer end 26 electrode leads 261 Folding section 262 Extension 40 Electrode body 70 battery cells W: Width direction of the battery cell (width direction of the battery case) D. Thickness direction of the battery cell (thickness direction of the battery case) TW overlap width Width of the outer edge of the CW3 battery case

Claims

1. An electrode body in which electrodes and separators are stacked alternately, A battery case that houses the electrode body inside, The battery case comprises an electrode lead, one end of which is connected to the electrode body inside the battery case, and the other end of which protrudes from the widthwise end of the battery case and is folded back toward the battery case side, The aforementioned battery case is One side surface in the thickness direction of the battery case is embossed, and a concave housing portion in which the electrode body is housed and an outer end portion provided outside the housing portion are formed therein. The other side surface of the battery case in the thickness direction is a non-embossed surface and is formed flat. The other end of the electrode lead is folded back toward the battery case and faces the non-embossed surface, and the overlap width in the thickness direction with respect to the battery case is wider than the width of the outer end. battery.

2. The other end of the electrode lead is It has a folded portion that is folded back toward the battery case side, and an extended portion that extends from the folded portion toward the upper side of the battery case and protrudes from the upper end of the battery case. The battery according to claim 1.

3. A battery module in which the battery described in Claim 1 is housed in a module case, Inside the module case, a plurality of the batteries are stacked along the thickness direction of the battery case, and the other end of the electrode lead is positioned between adjacent battery cases. Battery module.

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