battery cell

Abstract

To provide a battery cell having a high energy density and an efficient manufacturing process.SOLUTION: The housing includes a main body having a bottom and an opening facing the bottom, and a sealing plate having an outer edge joined to the main body and sealing the opening, the sealing plate including a first portion extending substantially parallel to the bottom and two second portions located farther from the bottom than the first portion, the second portion includes a first region extending substantially parallel to the first portion and a second region extending obliquely with respect to the first region and connecting the first portion and the first region, one of the second portions is disposed on one side of the first portion, the other of the second portions is disposed on the other side of the first portion, the first current collector tab and the second current collector tab are disposed at an end portion of the electrode body on a sealing plate side, and the first current collector tab is disposed between the one of the second portions and the bottom portion, the second current collecting tab is disposed between the other second portion and the bottom portion, and the first terminal and the second terminal are disposed in the first portion.SELECTED DRAWING: Figure 1

Description

[[Technical Field]]

[0001] The present technology relates to battery cells. [[Background Art]]

[0002] In a battery cell having a rectangular casing, unevenness is provided on the top surface of the casing, an electrode tab is housed inside the protrusion, and an electrode terminal is provided outside the recess, thereby securing storage space inside the casing while suppressing an increase in the overall height of the battery cell, and as a result, improving energy density.

[0003] Such battery cells are disclosed, for example, in Japanese Patent Application Laid-Open No. 2015-141798 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2015-149362 (Patent Document 2). [[Prior Art Documents]] [[Patent Documents]]

[0004] [[Patent Document 1]] Japanese Patent Application Laid-Open No. 2015-141798 [[Patent Document 2]] Japanese Patent Application Laid-Open No. 2015-149362 [[Patent Document 3]] Japanese Patent Application Laid-Open No. 2015-060827 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0005] In the battery cells disclosed in Patent Documents 1 and 2, focusing on improving energy density, a sealing plate constituting the top surface of the casing is vertically bent at a position adjacent to the electrode tab. As a result, in the vicinity of the bent portion, there arises a region where welding between the casing body and the sealing plate is difficult to perform.

[0006] An object of the present technology is to provide a battery cell having high energy density and an efficient manufacturing process. [[Means for Solving the Problem]]

[0007] This technology provides the following battery cells:

[0008] An electrode body including a first electrode and a second electrode; a rectangular housing for housing the electrode body; a first current collector tab provided on the first electrode; a second current collector tab provided on the second electrode; a first terminal electrically connected to the first current collector tab; a second terminal electrically connected to the second current collector tab; the housing includes a main body having a bottom and an opening facing the bottom; and a sealing plate having an outer edge joined to the main body and sealing the opening, the sealing plate including a first portion extending substantially parallel to the bottom and two second portions located further from the bottom than the first portion, the second portions being front A battery cell comprising a first region extending substantially parallel to a first portion and a second region extending diagonally to the first region and connecting the first portion and the first region, wherein one of the second portions is located on one side of the first portion and the other of the second portions is located on the other side of the first portion, the first current collector tab and the second current collector tab are located at the end of the electrode body on the sealing plate side, the first current collector tab is located between one of the second portions and the bottom, the second current collector tab is located between the other of the second portion and the bottom, and the first terminal and the second terminal are located in the first portion. [Effects of the Invention]

[0009] This technology makes it possible to provide battery cells with high energy density and an efficient manufacturing process. [Brief explanation of the drawing]

[0010] [Figure 1] This is a cross-sectional view of a battery cell according to Embodiment 1. [Figure 2] This is a cross-sectional view of a battery cell according to Embodiment 2. [Figure 3] This is a cross-sectional view of a battery cell relating to Comparative Example 1. [Figure 4] This is a cross-sectional view of a battery cell relating to Comparative Example 2. [Figure 5] This is a cross-sectional view of a battery cell relating to Comparative Example 3. [Figure 6] Figure 2 is a top view of the battery cell. [Figure 7] Figure 2 schematically illustrates the welding process of the sealing plate for the battery cell shown. [Figure 8] Figure 5 is a top view of the battery cell. [Figure 9] Figure 5 schematically illustrates the welding process of the sealing plate for the battery cell. [Figure 10] This is a cross-sectional view of a battery cell according to Embodiment 3. [Figure 11] This is a cross-sectional view of a battery cell according to Embodiment 4. [Modes for carrying out the invention]

[0011] Embodiments of this technology are described below. Note that the same or corresponding parts may be denoted by the same reference numerals, and their descriptions may not be repeated.

[0012] In the embodiments described below, when referring to the number, quantity, etc., unless otherwise specified, the scope of this technology is not necessarily limited to that number, quantity, etc. Also, in the embodiments described below, each component is not necessarily essential to this technology unless otherwise specified. Furthermore, this technology is not necessarily limited to achieving all of the effects and advantages mentioned in these embodiments.

[0013] In this specification, the terms "comprise," "include," and "have" are in open-ended form. That is, if a configuration includes one configuration, it may also include other configurations, or it may not.

[0014] Further, in the present specification, when geometric terms and terms representing positional and directional relationships are used, such as "parallel", "perpendicular", "oblique 45°", "coaxial", "along" and the like, these terms allow for manufacturing errors or slight variations. When terms representing relative positional relationships such as "upper side" and "lower side" are used in the present specification, these terms are used to indicate the relative positional relationship in one state, and the relative positional relationship can be reversed or rotated to any angle depending on the installation orientation of each mechanism (for example, when the entire mechanism is flipped upside down).

[0015] In the present specification, the term "battery" is not limited to lithium ion batteries, and may include other batteries such as nickel hydrogen batteries and sodium ion batteries.

[0016] In the present specification, when the terms "electricity storage cell" or "electricity storage module" are used, "electricity storage cell" or "electricity storage module" is not limited to a battery cell or a battery module, and may include a capacitor cell or a capacitor module.

[0017] In the present specification, the "battery cell" can be mounted on hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), battery electric vehicles (BEV) and the like. However, the application of the "battery cell" is not limited to in-vehicle use.

[0018] Figure 1 is a cross-sectional view of a battery cell according to Embodiment 1 of the present technology. As shown in Figure 1, the battery cell 1 includes an electrode assembly 100, a housing 200, and a conductive member 300.

[0019] The electrode assembly 100 includes a positive electrode tab 110 (first current collector tab) and a negative electrode tab 120 (second current collector tab). The electrode assembly 100 is composed of a positive electrode (first electrode), a negative electrode (second electrode), and a separator.

[0020] The positive electrode of the electrode body 100 has a structure in which a positive electrode active material mixture layer containing a positive electrode active material (e.g., lithium nickel cobalt manganese composite oxide, etc.), a binder (e.g., polyvinylidene fluoride (PVdF), etc.), and a conductive material (e.g., a carbon material, etc.) is formed on both sides of a positive electrode core body made of rectangular aluminum foil.

[0021] The negative electrode of the electrode body 100 has a structure in which a negative electrode active material mixture layer is formed on both sides of a negative electrode core body made of rectangular copper foil, for example.

[0022] The separator of the electrode body 100 is, for example, made of a rectangular polyolefin material. Alternatively, a long separator folded in a zigzag pattern may be used.

[0023] The positive electrode core and the negative electrode core protrude upward from the rectangular end of the electrode body 100, and these protruding positive electrode core and negative electrode core constitute the positive electrode tab 110 and the negative electrode tab 120, respectively.

[0024] The housing 200 houses the electrode body 100. The housing 200 includes the main body 210 and the sealing plate 220.

[0025] The main body 210 of the housing 200 has a bottom portion 211. An opening is formed in the portion of the main body 210 opposite the bottom portion. The opening is sealed by a sealing plate 220.

[0026] The sealing plate 220 of the housing 200 has an outer edge that is joined to the main body 210. By joining the outer edge of the sealing plate 220 to the main body 210, the main body 210 is sealed, and the electrode body 100 is sealed inside the housing 200. The joining of the main body 210 and the sealing plate 220 is performed, for example, by laser welding.

[0027] The sealing plate 220 includes a first portion 221 (recessed portion) and a second portion 222 (protruding portion). The first portion 221 extends substantially parallel to the bottom 211 of the main body 210. The second portion 222 is located further away from the bottom 211 of the main body 210 than the first portion 221. The second portion 222 protrudes in a direction away from the bottom 211 of the main body 210 than the first portion 221.

[0028] The second portion 222 of the sealing plate 220 includes a first region 2221 (horizontal region) and a second region 2222 (inclined region). The first region 2221 extends substantially parallel to the first portion 221. The second region 2222 extends diagonally to the first region 2221.

[0029] The conductive member 300 includes a positive electrode current collector 310 (first conductive member) and a negative electrode current collector 320 (second conductive member). The positive electrode current collector 310 is connected to the positive electrode tab 110 of the electrode body 100. The negative electrode current collector 320 is connected to the negative electrode tab 120 of the electrode body 100. The connection between the conductive member 300 and the positive electrode tab 110 and the negative electrode tab 120 is performed by welding, for example, ultrasonic welding, resistance welding, or laser welding. In laser welding, it is preferable to use a device that can arbitrarily change the focal length during welding, such as a laser welding machine equipped with a 3D galvanometer scanner.

[0030] The positive electrode current collector 310 and the negative electrode current collector 320 each penetrate the second portion 222 of the sealing plate 220 to reach the outside from the inside of the housing 200. More specifically, the positive electrode current collector 310 and the negative electrode current collector 320 each penetrate the second region 2222 (inclined region) in the second portion 222 of the sealing plate 220 to reach the outside from the inside of the housing 200. However, the positive electrode current collector 310 and the negative electrode current collector 320 may also penetrate the first region 2221 (horizontal region) to reach the outside of the housing 200.

[0031] By using a well-known hermetic sealing technique in the portion where the positive electrode current collector 310 and the negative electrode current collector 320 penetrate, it is possible to achieve both electrical connection inside and outside the housing 200 and sealing performance.

[0032] The positive electrode current collector 310 and the negative electrode current collector 320 are formed to conform to the shape of the sealing plate 220. The positive electrode current collector 310 and the negative electrode current collector 320 each have a portion that conforms to the first portion 221 of the sealing plate 220 and a portion that conforms to the first region 2221 (horizontal region) and the second region 2222 (inclined region) of the second portion 222 of the sealing plate 220.

[0033] The positive electrode current collector 310 includes a positive electrode terminal 311, and the negative electrode current collector 320 includes a negative electrode terminal 321. The positive electrode terminal 311 and the negative electrode terminal 321 are electrically connected to other battery cells via busbars (not shown). The positive electrode terminal 311 and the negative electrode terminal 321 are positioned on the first portion 221 (recessed portion) of the sealing plate 220.

[0034] In the battery cell 1, the positive electrode tab 110 and the negative electrode tab 120 of the electrode body 100 are located between the bottom 211 of the main body 210 of the housing 200 and the second portion 222 (protruding portion) of the sealing plate 220. More specifically, the positive electrode tab 110 and the negative electrode tab 120 are housed between the bottom 211 of the main body 210 and the first region 2221 (horizontal region) of the second portion 222 of the sealing plate 220. However, some or all of the positive electrode tab 110 and the negative electrode tab 120 may be housed between the bottom 211 and the second region 2222 (inclined region).

[0035] In the example of battery cell 1 shown in Figure 1, the second portion 222 of the sealing plate 220 includes two protrusions 222α and 222β (first protrusion and second protrusion) located at both ends of the housing 200 in the direction in which the positive electrode current collector 310 and the negative electrode current collector 320 are aligned (left-right direction in the figure). The positive electrode tab 110 is located inside the protrusion 222α, and the negative electrode tab 120 is located inside the protrusion 222β. The protrusion heights of the protrusions 222α and 222β from the first portion 221 are approximately the same.

[0036] When manufacturing the battery cell 1, an electrode body 100 including a positive electrode and a negative electrode is formed, and the positive electrode current collector 310 and the negative electrode current collector 320 are attached to the sealing plate 220. Next, the positive electrode tab 110 and the positive electrode current collector 310 are electrically connected, and the negative electrode tab 120 and the negative electrode current collector 320 are electrically connected. In this state, the electrode body 100 is housed in the main body 210 of the housing 200, and the opening of the main body 210 is sealed with the sealing plate 220.

[0037] In the example of the battery cell 1 shown in Figure 1, the width of the housing 200 in the left-right direction in the figure is the total width (W) of the battery cell 1, and the height of the housing 200 in the up-down direction in the figure is the total height (H) of the battery cell 1. In a preferred example, the ratio of the total width (W) to the total height (H) (W / H) of the battery cell 1 is greater than 1 (more preferably 1.5 or more, and even more preferably 2 or more).

[0038] Figure 2 is a cross-sectional view of a battery cell 1 according to Embodiment 2. The battery cell 1 shown in Figure 2 is a modified example of the example in Figure 1, and similar to the example in Figure 1, the positive electrode terminal 311 and the negative electrode terminal 321 are located on the first portion 221 (recessed portion) of the sealing plate 220, and the positive electrode tab 110 and the negative electrode tab 120 of the electrode body 100 are housed inside the second portion 222 (protruding portion) of the sealing plate 220.

[0039] In the example shown in Figure 2, unlike in Figure 1, the second portion 222 of the sealing plate 220 is composed of a single protrusion 222α located in the center of the housing 200 in the direction in which the positive electrode current collector 310 and the negative electrode current collector 320 are aligned (left-right direction in the figure). The positive electrode tab 110 and the negative electrode tab 120 are located inside the common protrusion 222α.

[0040] Figures 3 to 5 are cross-sectional views of battery cells 1A, 1B, and 1C according to Comparative Examples 1 to 3, respectively. In the Comparative Examples shown in Figures 3 to 5, battery cells 1A, 1B, and 1C each include electrode bodies 100A, 100B, and 100C, housings 200A, 200B, and 200C, and conductive members 300A, 300B, and 300C, respectively.

[0041] Each electrode assembly 100A, 100B, and 100C includes positive electrode tabs 110A, 110B, and 110C, and negative electrode tabs 120A, 120B, and 120C, respectively.

[0042] Enclosures 200A, 200B, and 200C each include a main body 210A, 210B, and 210C, and sealing plates 220A, 220B, and 220C, respectively. The main bodies 210A, 210B, and 210C each have a bottom section 211A, 211B, and 211C, respectively.

[0043] The conductive members 300A, 300B, and 300C include positive electrode current collectors 310A, 310B, and 310C, and negative electrode current collectors 320A, 320B, and 320C. The positive electrode current collectors 310A, 310B, and 310C each include positive electrode terminals 311A, 311B, and 311C, respectively, and the negative electrode current collectors 320A, 320B, and 320C each include negative electrode terminals 321A, 321B, and 321C, respectively.

[0044] In battery cells 1A, 1B, and 1C shown in Figures 3 to 5, the shape of the housings 200A, 200B, and 200C differs from that of battery cell 1 shown in Figures 1 and 2.

[0045] Specifically, in the example of battery cell 1A shown in Figure 3, the sealing plate 220A is formed in a flat shape, and there are no recessed portions (corresponding to the first portion 221) or convex portions (corresponding to the second portion 222). Therefore, outside the housing 200A, the positive electrode terminal 311A ​​and the negative electrode terminal 321A protrude above the sealing plate 220A, and inside the housing 200A, the main body of the electrode body 100A and the sealing plate 220A are separated by the height of the positive electrode tab 110A and the negative electrode tab 120A. As a result, although the total height of battery cells 1A, 1B, and 1C shown in Figures 3 to 5 is approximately the same, the height of the electrode body 100A of battery cell 1A is lower than the heights of the electrode bodies 100B and 100C of battery cells 1B and 1C, and the energy density of battery cell 1A when modularized is relatively lower than that of battery cells 1B and 1C.

[0046] In contrast, in the example of battery cells 1B and 1C shown in Figures 4 and 5, the sealing plates 220B and 220C each have a first portion 221B and 221C (recessed portion) and a second portion 222B and 222C (convex portion). The positive terminals 311B and 311C and the negative terminals 321B and 321C are located on the first portion 221B and 221C (recessed portion), and the positive tabs 110B and 110C and the negative tabs 120B and 120C are housed inside the second portion 222B and 222C (convex portion). Therefore, the energy density when battery cells 1B and 1C are modularized is relatively higher than that of battery cell 1A.

[0047] However, in battery cells 1B and 1C in Figures 4 and 5, the sealing plates 220B and 220C are bent vertically between the first parts 221B and 221C and the second parts 222B and 222C, and there is no portion extending diagonally from the first parts 221B and 221C (corresponding to the second region 2222) in the second parts 222B and 222C.

[0048] As a result, battery cells 1B and 1C still face challenges in terms of efficiency in the manufacturing process. This point will be explained using Figures 6 to 9.

[0049] Figure 6 is a top view of the battery cell 1 shown in Figure 2 (Embodiment 2), and Figure 7 is a schematic diagram showing the sealing plate welding process of its housing 200.

[0050] As shown in Figure 7, laser light 21 is irradiated from the laser light source 20 toward the sealing plate 220. The boundary 10 between the first portion 221 and the second portion 222 of the sealing plate 220 is irradiated with laser light 21 from a direction at an angle φ with respect to the first portion 221. At this time, by setting the intersection angle (θ) of the second region 2222 (inclined region) of the second portion 222 with respect to the first portion 221 to be larger than the angle φ, the laser light 21 can be irradiated to the boundary 10 without moving the laser light source 20, or if it is moved, only by a small distance.

[0051] In the embodiment of this technology, the intersection angle (θ) between the first portion 221 and the second region 2222 of the second portion 222 is greater than 90° and less than 180°. More preferably, the intersection angle (θ) is about 120° or more and 150° or less, and even more preferably, it is about 135° or more and 150° or less.

[0052] Figure 8 is a top view of the battery cell 1C shown in Figure 5 (Comparative Example 3), and Figure 9 is a schematic diagram showing the sealing plate welding process of its housing 200C.

[0053] As shown in Figure 9, laser light 21 is irradiated from the laser light source 20 toward the sealing plate 220C. At this time, near the boundary 10C between the first portion 221C and the second portion 222C of the sealing plate 220C, the laser light 21 from the laser light source 20 is blocked by the step between the first portion 221C and the second portion 222C. Therefore, near the boundary 10C, it becomes necessary to move the laser light source 20 in the left-right direction in the figure in order to laser weld the main body 210C of the housing 200C and the sealing plate 220C. As a result, the efficiency of the manufacturing process may be hindered.

[0054] Thus, in the battery cells 1B and 1C shown in Figures 4 and 5, by vertically bending the sealing plates 220B and 220C at positions adjacent to the positive electrode tabs 110B and 110C and the negative electrode tabs 120B and 120C, the energy density can be improved compared to the battery cell 1A shown in Figure 3. However, near these bent portions, there are areas where welding between the main body 210B and 210C of the housing 200B and 200C and the sealing plates 220B and 220C is difficult, and as a result, the efficiency of the manufacturing process is hindered.

[0055] In contrast, in the battery cell 1 according to embodiments 1 and 2 of this technology, the energy density can be improved and the manufacturing process can be made more efficient by making the first portion 221 and the second region 2222 of the second portion 222 of the sealing plate 220 intersect at an angle.

[0056] The scope of this technology is not limited to the structures illustrated in Figures 1 and 2. For example, while the examples in Figures 1 and 2 show a structure in which both the positive electrode tab 110 and the negative electrode tab 120 are housed inside the second portion 222 (protruding portion) of the sealing plate 220, a structure in which only one of the positive electrode tab 110 or the negative electrode tab 120 is housed inside the second portion 222 (protruding portion) of the sealing plate 220 is also possible.

[0057] Furthermore, while the examples in Figures 1 and 2 show a structure in which the housing 200 has a symmetrical shape in the left-right direction in the figures, as shown in Figures 10 (Embodiment 3) and 11 (Embodiment 4), the housing 200 may have an asymmetrical shape in the left-right direction in the figures.

[0058] While embodiments of the present technology have been described above, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present technology is defined by the claims, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0059] 1,1A,1B,1C battery cell, 10,10C boundary, 20 laser light source, 21 laser light, 100,100A,100B,100C electrode body, 110,110A,110B,110C positive electrode tab, 120,120A,120B,120C Negative electrode tab, 200,200A,200B,200C Housing, 210,210A,210B,210C Main body, 211,211A,211B,211C Bottom, 220,220A,220B,220C Sealing plate, 221,221B,221C First part, 222,222B,222C Second part, 222α,222β Convex portion, 300, 300A, 300B, 300C Conductive member, 310, 310A, 310B, 310C Positive electrode current collector, 311, 311A, 311B, 311C Positive electrode terminal, 320, 320A, 320B, 320C Negative electrode current collector, 321, 321A, 321B, 321C Negative electrode terminal, 2221 First region, 2222 Second region.

Claims

1. An electrode body including a first electrode and a second electrode, A rectangular housing for housing the electrode body, A first current collector tab provided on the first electrode, A second current collector tab provided on the second electrode, A first terminal electrically connected to the first current collector tab, The second current collector tab is electrically connected to a second terminal, The housing includes a main body having a bottom and an opening facing the bottom, and a sealing plate having an outer edge joined to the main body and sealing the opening, The sealing plate includes a first portion extending substantially parallel to the bottom and two second portions located further from the bottom than the first portion. The second portion includes a first region extending substantially parallel to the first portion, and a second region extending diagonally to the first region and connecting the first portion and the first region. The second part is positioned on one side of the first part. The other second portion is positioned on the other side of the first portion, The first current collector tab and the second current collector tab are positioned at the end of the electrode body on the sealing plate side. The first current collector tab is positioned between the second portion and the bottom portion. The second current collector tab is positioned between the other second portion and the bottom portion. The first terminal and the second terminal are located in the first part of the battery cell.

2. The battery cell according to claim 1, wherein the projection height of each of the two second portions from the first portion is substantially the same as that of the first portion.

3. The battery cell according to claim 1 or claim 2, wherein the ratio of the total width (W) to the total height (H) of the battery cell (W / H) is greater than 1.

4. The battery cell according to claim 1 or claim 2, wherein the intersection angle between the first portion and the second region of the second portion is greater than 90° and less than 180°.

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