Battery cell
The battery cell design with a sealing plate having parallel and oblique portions addresses welding challenges, enhancing energy density and manufacturing efficiency.
Patent Information
- Application Number
- JP2025189187
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-11-10
- Publication Date
- 2026-02-03
AI Technical Summary
Existing battery cells face challenges in achieving high energy density and efficient manufacturing processes due to difficulties in welding the housing body and sealing plate at bent portions near the electrode tabs.
A battery cell design featuring a rectangular housing with a sealing plate that includes parallel and oblique portions, allowing current collectors to penetrate and connect electrode tabs efficiently, thereby improving energy density and manufacturing efficiency.
The design achieves high energy density and enhances manufacturing efficiency by facilitating easier welding and reducing the overall height of the battery cell.
Smart Images
Figure 2026016807000001_ABST
Abstract
Description
[Technical Field]
[0001] The present technology relates to battery cells. [Background technology]
[0002] In a battery cell having a rectangular housing, by providing projections and recesses on the top surface of the housing, storing electrode tabs inside the projections, and providing electrode terminals outside the recesses, it is possible to secure storage space inside the housing while suppressing an increase in the height of the battery cell as a whole, and as a result, improve the energy density.
[0003] Such battery cells are shown in, for example, 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 shown in Patent Documents 1 and 2, the sealing plate that forms the top surface of the housing is bent vertically at a position adjacent to the electrode tab in order to improve energy density. As a result, there are areas near the bent portion where it is difficult to weld the housing body and the sealing plate.
[0006] An object of the present technology is to provide a battery cell with high energy density and an efficient manufacturing process. [Means for solving the problem]
[0007] The present technology provides the following battery cell.
[0008] an electrode assembly including a first electrode and a second electrode; a rectangular housing that houses the electrode assembly; a first current collecting tab provided on the first electrode; a second current collecting tab provided on the second electrode; a first terminal electrically connected to the first current collecting tab; and a second terminal electrically connected to the second current collecting 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 positioned farther from the bottom than the first portions, a first region extending substantially parallel to the first portion; and a second region extending obliquely relative to the first region and connecting the first portion and the first region, one of the second portions being disposed on one side of the first portion and the other of the second portions being disposed on the other side of the first portion, the first current collecting tab and the second current collecting tab being disposed at an end of the electrode body on the sealing plate side, the first current collecting tab being disposed between one of the second portions and the bottom, and the second current collecting tab being disposed between the other of the second portions and the bottom, and the first terminal and the second terminal being disposed on the first portions. [Effects of the Invention]
[0009] According to the present technology, it is possible to provide a battery cell with high energy density and an efficient manufacturing process. [Brief explanation of the drawings]
[0010] [Figure 1] FIG. 2 is a cross-sectional view of a battery cell according to the first embodiment. [Figure 2] FIG. 10 is a cross-sectional view of a battery cell according to a second embodiment. [Figure 3] FIG. 2 is a cross-sectional view of a battery cell according to Comparative Example 1. [Figure 4] FIG. 10 is a cross-sectional view of a battery cell according to Comparative Example 2. [Figure 5] FIG. 10 is a cross-sectional view of a battery cell according to Comparative Example 3. [Figure 6] FIG. 3 is a top view of the battery cell shown in FIG. [Figure 7] 3 is a diagram showing a schematic diagram of a sealing plate welding process for the battery cell shown in FIG. 2. [Figure 8] FIG. 6 is a top view of the battery cell shown in FIG. [Figure 9] 6 is a diagram showing a schematic diagram of a sealing plate welding step for the battery cell shown in FIG. 5. [Figure 10] FIG. 10 is a cross-sectional view of a battery cell according to a third embodiment. [Figure 11] FIG. 10 is a cross-sectional view of a battery cell according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION
[0011] Hereinafter, embodiments of the present technology will be described. Note that the same or corresponding parts are denoted by the same reference characters, and description thereof may not be repeated.
[0012] In the embodiments described below, when numbers, amounts, etc. are mentioned, the scope of the present technology is not necessarily limited to those numbers, amounts, etc., unless otherwise specified. Furthermore, in the embodiments described below, each component is not necessarily essential to the present technology, unless otherwise specified. Furthermore, the present technology is not necessarily limited to those that achieve all of the effects and advantages mentioned in the present embodiments.
[0013] In this specification, the terms "comprise," "include," and "have" are open-ended. That is, when a certain feature is included, other features may or may not be included.
[0014] Furthermore, when geometric terms and terms expressing positional and directional relationships are used in this specification, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along," these terms allow for manufacturing errors and slight variations. When terms expressing relative positional relationships, such as "upper side" and "lower side," are used in this specification, these terms are used to indicate relative positional relationships in a single state, and the relative positional relationships can be reversed or rotated to any angle depending on the installation direction of each mechanism (for example, by turning the entire mechanism upside down).
[0015] 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.
[0016] In this specification, when the terms "storage cell" or "storage module" are used, the "storage cell" or "storage module" is not limited to a battery cell or battery module, but may also include a capacitor cell or capacitor module.
[0017] In this specification, a "battery cell" can be installed in a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), an electric vehicle (BEV), etc. However, the use of a "battery cell" is not limited to in-vehicle use.
[0018] 1 is a cross-sectional view of a battery cell according to embodiment 1 of the present technology. As shown in FIG. 1, the battery cell 1 includes an electrode body 100, a housing 200, and a conductive member 300.
[0019] The electrode assembly 100 includes a positive electrode tab 110 (first current collecting tab) and a negative electrode tab 120 (second current collecting tab). The electrode assembly 100 is made up 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), a binder (e.g., polyvinylidene fluoride (PVdF)), and a conductive material (e.g., carbon material) is formed on both sides of a positive electrode core made of rectangular aluminum foil.
[0021] The negative electrode of the electrode assembly 100 has a structure in which negative electrode active material mixture layers are formed on both sides of a negative electrode core made of, for example, a rectangular copper foil.
[0022] The separator of the electrode assembly 100 is made of, for example, a rectangular polyolefin member. Alternatively, a long separator may be folded zigzag.
[0023] The positive electrode core and negative electrode core protrude upward in the figure from the end sides of the rectangular main body of the electrode assembly 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 assembly 100. The housing 200 includes a main body 210 and a sealing plate 220.
[0025] The main body 210 of the housing 200 has a bottom 211. An opening is formed in a portion of the main body 210 facing the bottom. The opening is sealed with 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 in the internal space of the housing 200. The main body 210 and the sealing plate 220 are joined by, for example, 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 farther 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 obliquely relative 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 assembly 100. The negative electrode current collector 320 is connected to the negative electrode tab 120 of the electrode assembly 100. The conductive member 300 is connected to the positive electrode tab 110 and the negative electrode tab 120 by welding, such as ultrasonic welding, resistance welding, or laser welding. For 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 from the inside to the outside 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 from the inside to the outside 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 at the portions where the positive electrode current collector 310 and the negative electrode current collector 320 penetrate, it is possible to achieve both electrical connection between the inside and outside of the housing 200 and sealing properties.
[0032] The positive electrode current collector 310 and the negative electrode current collector 320 are formed to fit 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 fits along the first portion 221 of the sealing plate 220, and a portion that fits along 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 a bus bar (not shown). The positive electrode terminal 311 and the negative electrode terminal 321 are provided so as to be located 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 assembly 100 are located between the bottom 211 of the main body 210 of the casing 200 and the second portion 222 (convex 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 a first region 2221 (horizontal region) of the second portion 222 of the sealing plate 220. However, part 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] 1, the second portion 222 of the sealing plate 220 includes two protrusions 222α and 222β (first and second protrusions) 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 (the 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 protrusions 222α and 222β protrude from the first portion 221 to approximately the same height.
[0036] When manufacturing the battery cell 1, the electrode assembly 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 assembly 100 is housed in the main body 210 of the casing 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 Fig. 1, the width of the casing 200 in the left-right direction in the figure is the overall width (W) of the battery cell 1, and the height of the casing 200 in the up-down direction in the figure is the overall height (H) of the battery cell 1. In a preferred example, the ratio (W / H) of the overall width (W) to the overall height (H) of the battery cell 1 is greater than 1 (more preferably 1.5 or greater, and even more preferably 2 or greater).
[0038] Fig. 2 is a cross-sectional view of a battery cell 1 according to embodiment 2. The battery cell 1 shown in Fig. 2 is a modified example of the example in Fig. 1, and similar to the example in Fig. 1, the positive electrode terminal 311 and the negative electrode terminal 321 are located on a 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 a second portion 222 (protruding portion) of the sealing plate 220.
[0039] 2, unlike in Fig. 1, the second portion 222 of the sealing plate 220 is configured by one protrusion 222α located in the center of the casing 200 in the direction in which the positive electrode current collector 310 and the negative electrode current collector 320 are aligned (the 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. In the comparative examples shown in Figures 3 to 5, battery cells 1A, 1B, and 1C include electrode bodies 100A, 100B, and 100C, housings 200A, 200B, and 200C, and conductive members 300A, 300B, and 300C, respectively.
[0041] The electrode assemblies 100A, 100B, and 100C include positive electrode tabs 110A, 110B, and 110C and negative electrode tabs 120A, 120B, and 120C, respectively.
[0042] The housings 200A, 200B, and 200C include main bodies 210A, 210B, and 210C and sealing plates 220A, 220B, and 220C, respectively. The main bodies 210A, 210B, and 210C have bottoms 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 include positive electrode terminals 311A, 311B, and 311C, respectively, and the negative electrode current collectors 320A, 320B, and 320C include negative electrode terminals 321A, 321B, and 321C, respectively.
[0044] In the battery cells 1A, 1B, and 1C shown in FIGS. 3 to 5, the shapes of the casings 200A, 200B, and 200C are different from those of the battery cell 1 shown in FIGS.
[0045] Specifically, in the example of the battery cell 1A shown in FIG. 3, the sealing plate 220A is formed in a flat plate shape, and does not have a recessed portion (corresponding to the first portion 221) or a protruding portion (corresponding to the second portion 222). Therefore, outside the casing 200A, the positive electrode terminal 311A and the negative electrode terminal 321A protrude above the sealing plate 220A, and inside the casing 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 overall heights of the battery cells 1A, 1B, and 1C shown in FIGS. 3 to 5 are approximately the same, the height of the electrode body 100A of the battery cell 1A is lower than the heights of the electrode bodies 100B and 100C of the battery cells 1B and 1C, and the energy density when the battery cell 1A is modularized is relatively lower than that of the battery cells 1B and 1C.
[0046] In contrast, in the examples of battery cells 1B and 1C shown in Figures 4 and 5, sealing plates 220B and 220C have first portions 221B and 221C (recessed portions) and second portions 222B and 222C (protruding portions), respectively. Positive electrode terminals 311B and 311C and negative electrode terminals 321B and 321C are located on the first portions 221B and 221C (recessed portions), and positive electrode tabs 110B and 110C and negative electrode tabs 120B and 120C are housed inside the second portions 222B and 222C (protruding portions). Therefore, the energy density of battery cells 1B and 1C when modularized is higher than that of battery cell 1A.
[0047] However, in the battery cells 1B, 1C of Figures 4 and 5, the sealing plates 220B, 220C are bent vertically between the first portions 221B, 221C and the second portions 222B, 222C, and there is no portion in the second portions 222B, 222C that extends obliquely relative to the first portions 221B, 221C (corresponding to the second region 2222).
[0048] As a result, problems still remain in terms of efficiency in the manufacturing process for the battery cells 1B and 1C. This will be explained with reference to FIGS.
[0049] FIG. 6 is a top view of the battery cell 1 shown in FIG. 2 (Embodiment 2), and FIG. 7 is a diagram schematically showing the process of welding the sealing plate of the casing 200. As shown in FIG.
[0050] 7, laser light 21 is irradiated from laser light source 20 toward sealing plate 220. A boundary 10 between a first portion 221 and a second portion 222 of sealing plate 220 is irradiated with laser light 21 from a direction at an angle φ with respect to first portion 221. At this time, by setting the intersection angle (θ) of second region 2222 (inclined region) of second portion 222 with respect to first portion 221 to be larger than angle φ, it is possible to irradiate laser light 21 onto boundary 10 without moving laser light source 20, or by moving it only a short distance if laser light source 20 is moved.
[0051] In the embodiment of the present 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 smaller than 180°. More preferably, the intersection angle (θ) is approximately equal to or greater than 120° and equal to or less than 150°, and even more preferably, is approximately equal to or greater than 135° and equal to or less than 150°.
[0052] FIG. 8 is a top view of the battery cell 1C shown in FIG. 5 (Comparative Example 3), and FIG. 9 is a diagram schematically showing the process of welding the sealing plate of the casing 200C.
[0053] 9, laser light 21 is emitted from laser light source 20 toward sealing plate 220C. At this time, near boundary 10C between first portion 221C and second portion 222C of sealing plate 220C, a portion where laser light 21 from laser light source 20 is blocked by a step between first portion 221C and second portion 222C is generated. Therefore, in order to laser-weld main body 210C of casing 200C and sealing plate 220C near boundary 10C, it becomes necessary to move laser light source 20 in the left-right direction in the figure. As a result, the efficiency of the manufacturing process may be hindered.
[0054] In this way, in the battery cells 1B, 1C shown in FIGS. 4 and 5, by bending the sealing plates 220B, 220C vertically at positions adjacent to the positive electrode tabs 110B, 110C and the negative electrode tabs 120B, 120C, the energy density can be improved compared to the battery cell 1A shown in FIG. 3. However, there are locations near these bent portions where it is difficult to weld the main bodies 210B, 210C of the casings 200B, 200C to the sealing plates 220B, 220C, and this results in an impeded efficiency in the manufacturing process.
[0055] In contrast, in the battery cell 1 according to embodiments 1 and 2 of the present technology, the first portion 221 of the sealing plate 220 and the second region 2222 of the second portion 222 are diagonally intersected, thereby improving the energy density and streamlining the manufacturing process.
[0056] The scope of the present technology is not limited to the structures exemplified in Fig. 1 and Fig. 2. For example, the example in Fig. 1 and Fig. 2 shows a structure in which both the positive electrode tab 110 and the negative electrode tab 120 are housed inside the second portion 222 (convex portion) of the sealing plate 220, but a structure in which only one of the positive electrode tab 110 and the negative electrode tab 120 is housed inside the second portion 222 (convex portion) of the sealing plate 220 may also be used.
[0057] Furthermore, in the examples of Figures 1 and 2, a structure is shown in which the housing 200 has a symmetrical shape in the left-right direction in the figures, but as shown in Figure 10 (embodiment 3) and Figure 11 (embodiment 4), the housing 200 may have an asymmetrical shape in the left-right direction in the figures.
[0058] Although the embodiments of the present technology have been described above, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present technology is defined by the claims, and it is intended to include all modifications within the meaning and scope of the claims. [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 assembly including a first electrode and a second electrode; a square housing that houses the electrode body; a first current collecting tab provided on the first electrode; a second current collecting tab provided on the second electrode; a first terminal electrically connected to the first current collecting tab; a second terminal electrically connected to the second current collecting 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 includes a first portion extending substantially parallel to the bottom portion and two second portions positioned farther from the bottom portion 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 second portion is disposed on the other side of the first portion, the first current collecting tab and the second current collecting tab are disposed on an end of the electrode body on the sealing plate side, the first current collecting tab is disposed between one of the second portions and the bottom; the second current collecting tab is disposed between the other second portion and the bottom; The first terminal and the second terminal are disposed in the first portion.
2. The battery cell according to claim 1 , wherein the two second portions protrude from the first portion by approximately the same height.
3. 3. The battery cell according to claim 1, wherein a ratio (W / H) of an overall width (W) to an overall height (H) of the battery cell is greater than 1.
4. 3. The battery cell according to claim 1, wherein an intersection angle between the first portion and the second region of the second portion is greater than 90 degrees and smaller than 180 degrees.
Citation Information
Patent Citations
Secondary battery
JP2015060827A
Power storage device
JP2015141798A
Power storage device
JP2015149362A