Battery cell

Abstract

To reduce the thickness of a lid material in the state of securing the strength of the lid material.SOLUTION: A battery cell 10 comprises: a battery element 100; a front lid material 210 for covering one end of the battery element 100; an outer packaging film 300 that is at least partially wound around the battery element 100; and a rib 212 that is provided in the front lid material 210.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a battery cell. [Background technology]

[0002] In recent years, various structures of battery cells, such as lithium-ion secondary battery cells, have been developed. For example, a battery cell described in Patent Document 1 includes a battery element, two lid members, and an exterior film. The two lid members cover both longitudinal ends of the battery element. The exterior film is wrapped around the battery element in the longitudinal direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-108623 Summary of the Invention [Problem to be solved by the invention]

[0004] The thickness of the lid material may be reduced to meet certain demands such as improving volumetric energy density, etc. However, simply reducing the thickness of the lid material may make it difficult to ensure the strength of the lid material.

[0005] One example of an object of the present invention is to reduce the thickness of a lid material while ensuring the strength of the lid material. Other objects of the present invention will become apparent from the description of this specification. [Means for solving the problem]

[0006] One aspect of the present invention is as follows. [1] A battery element; a lid member covering one end of the battery element; an exterior film at least partially wrapped around the battery element; A rib provided on the lid material; A battery cell comprising: [2] At least a portion of the rib defines a space that communicates with the storage space formed by the lid material and the exterior film. Definition death attitude The battery cell according to [1]. [3] Further comprising a current collector drawn out from the battery element, The battery cell according to [1] or [2], wherein the height of the rib in a region where the rib does not overlap with the current collector in the protruding direction of the rib is higher than the height of the rib in a region where the rib overlaps with the current collector in the protruding direction of the rib. [4] Further comprising a current collector drawn out from the battery element, the ribs are provided in a region that does not overlap with the current collector in a protruding direction of the ribs, The battery cell according to [1] or [2], wherein the ribs are not provided in an area that overlaps with the current collector in the protruding direction of the ribs. [5] a current collector having a folded portion folded inside the lid member and a folded portion bent relative to the folded portion, the current collector being drawn out from the battery element; The battery cell according to [1] or [2], wherein the height of the rib in the region where the rib protrudes and overlaps with the folded portion of the current collector is greater than the height of the rib in the region where the rib protrudes and overlaps with the folded portion of the current collector. [6] a current collector having a folded portion folded inside the lid member and a folded portion bent relative to the folded portion, the current collector being drawn out from the battery element; the rib is provided in a region overlapping the folded portion of the current collector in a protruding direction of the rib, The battery cell according to [1] or [2], wherein the rib is not provided in an area that overlaps with the folded portion of the current collector in the protruding direction of the rib. [Effects of the Invention]

[0007] According to the above aspect of the present invention, the thickness of the lid material can be reduced while ensuring the strength of the lid material. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a front perspective view of a battery cell according to the embodiment. [Figure 2] FIG. 2 is an enlarged front perspective view of a portion of a battery cell according to an embodiment. [Figure 3] FIG. 2 is a right side view of the battery cell according to the embodiment. [Figure 4] FIG. 2 is a rear view of the front lid member according to the embodiment. [Figure 5] FIG. 10 is a side view of a portion of a battery cell according to Modification 1. [Figure 6] FIG. 10 is a rear view of the front cover member according to the first modification. [Figure 7] FIG. 10 is a side view of a portion of a battery cell according to Modification 2. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments and modifications of the present invention will be described with reference to the drawings. In all the drawings, like components are designated by like reference numerals, and descriptions thereof will be omitted as appropriate.

[0010] Fig. 1 is a front perspective view of a battery cell 10 according to an embodiment. Fig. 2 is an enlarged front perspective view of a portion of the battery cell 10 according to an embodiment. Fig. 3 is a right side view of the battery cell 10 according to an embodiment. For the sake of explanation, Fig. 3 shows an exterior film 300 in a see-through state.

[0011] For the sake of explanation, each figure is labeled with an X direction, a Y direction, and a Z direction. The X direction indicates the front-to-rear direction of the battery cell 10. The Y direction is perpendicular to the X direction. The Y direction indicates the left-to-right direction of the battery cell 10. The Z direction is perpendicular to both the X direction and the Y direction. The Z direction indicates the up-to-down direction of the battery cell 10. The direction indicated by the arrow indicating the X direction, the direction indicated by the arrow indicating the Y direction, and the direction indicated by the arrow indicating the Z direction are the rearward, leftward, and upward directions, respectively. However, the relationships between the X direction, Y direction, Z direction, front-to-rear direction, left-to-right direction, and up-to-down direction of the battery cell 10 are not limited to this example.

[0012] Note that a white circle with an X indicating the X, Y, or Z direction indicates that the direction from the front of the page to the back is the direction indicated by the arrow indicating that direction. A white circle with a black dot indicating the X, Y, or Z direction indicates that the direction from the back of the page to the front is the direction indicated by the arrow indicating that direction.

[0013] The battery cell 10 includes a battery element 100, a positive electrode tab 110, a negative electrode tab 120, a front cover member 210, a rear cover member 220, and an exterior film 300. The exterior film 300 has a wound portion 302 and a pulled-out portion 304.

[0014] The battery element 100 has a substantially rectangular parallelepiped shape. The longitudinal direction of the battery element 100 is substantially parallel to the X direction. The length of the battery element 100 in the X direction is not limited to, but is, for example, 300 mm to 500 mm, and preferably 450 mm or less. The lateral direction of the battery element 100 is substantially parallel to the Z direction. The length of the battery element 100 in the Z direction is not limited to, but is, for example, 90 mm to 130 mm, and preferably 120 mm or less. The thickness direction of the battery element 100 is substantially parallel to the Y direction. The thickness of the battery element 100 in the Y direction is not limited to, but is, for example, 20 mm to 50 mm, and preferably 45 mm or less. However, the shape of the battery element 100 is not limited to this example.

[0015] The battery element 100 includes at least one positive electrode (not shown), at least one negative electrode (not shown), and at least one separator (not shown). For example, multiple positive electrodes and multiple negative electrodes are alternately stacked in the Y direction. At least a portion of the separator is located between adjacent positive and negative electrodes in the Y direction. For example, multiple sheet-like separators may each be located between adjacent positive and negative electrodes in the Y direction. Alternatively, a zigzag separator may be alternately folded back at both ends in the Z direction. In this example, the portion of the separator located between both ends in the Z direction is located between adjacent positive and negative electrodes in the Y direction. Alternatively, the positive electrode, negative electrode, and separator may be wound so that the separator is located between the positive and negative electrodes. In one example, the positive electrode, negative electrode, and separator are wound with both sides of one of the positive and negative electrodes covered by the separator. In another example, a laminate including a plurality of unit laminates each including a positive electrode, a separator, and a negative electrode in this order may be wound, but the winding structure of the positive electrode, the negative electrode, and the separator is not limited to these examples.

[0016] 3, the positive electrode tab 110 is disposed at the front of the battery element 100. The positive electrode tab 110 is electrically connected to the positive electrode current collector 102a. The positive electrode current collector 102a is drawn out toward the front from the positive electrode of the battery element 100. In this way, the positive electrode tab 110 is electrically connected to the multiple positive electrodes of the battery element 100.

[0017] 3, the negative electrode tab 120 is disposed at the rear of the battery element 100. The negative electrode tab 120 is electrically connected to the negative electrode current collector 104a. The negative electrode current collector 104a is pulled out rearward from the negative electrode of the battery element 100. In this way, the negative electrode tab 120 is electrically connected to the multiple negative electrodes of the battery element 100.

[0018] The front cover member 210 covers the front end portion of the battery element 100. The front cover member 210 is made of, for example, resin, metal, or the like. The front end portion of the positive electrode tab 110 protrudes from the front surface of the front cover member 210. When viewed from the front, the front cover member 210 has a substantially rectangular shape. When viewed from the front, the longitudinal direction of the front cover member 210 is substantially parallel to the Z direction, and the lateral direction of the front cover member 210 is substantially parallel to the Y direction.

[0019] The rear cover member 220 covers the rear end portion of the battery element 100. The rear cover member 220 is made of, for example, resin, metal, or the like. The rear end portion of the negative electrode tab 120 protrudes from the rear surface of the rear cover member 220. When viewed from the rear, the rear cover member 220 has a substantially rectangular shape. When viewed from the rear, the longitudinal direction of the rear cover member 220 is substantially parallel to the Z direction, and the lateral direction of the rear cover member 220 is substantially parallel to the Y direction.

[0020] As shown in FIGS. 1 and 2 , the wound portion 302 has a generally cylindrical shape that is open both front and rear. A front cover member 210 is disposed inside the front opening of the wound portion 302. A rear cover member 220 is disposed inside the rear opening of the wound portion 302. The wound portion 302 is wound around the battery element 100, the front cover member 210, and the rear cover member 220 in the X direction by one turn. As a result, the front cover member 210, the rear cover member 220, and the wound portion 302 form a storage space 500 that stores the battery element 100. The storage space 500 stores the battery element 100 as well as an electrolyte (not shown). The manner in which the wound portion 302 wraps around the battery element 100 is not limited to the example described above.

[0021] The outer peripheral surface of the front lid member 210 in the X direction and the inner peripheral surface of the front opening of the wound portion 302 in the X direction are joined to each other by, for example, heat fusion, thereby forming the front sealing portion 510.

[0022] The outer peripheral surface of the rear lid member 220 in the X direction and the inner peripheral surface of the rear opening of the wound portion 302 in the X direction are joined to each other by, for example, heat fusion, thereby forming the rear sealing portion 520.

[0023] As shown in FIGS. 1 and 2 , the pull-out portion 304 is pulled out from the upper left corner of the wound portion 302 of the battery element 100 when viewed from the front. Specifically, as shown in FIG. 2 , the pull-out portion 304 includes a first pull-out portion 304a and a second pull-out portion 304b. The first pull-out portion 304a is pulled out from one of the circumferential ends of the wound portion 302 in the X direction. The second pull-out portion 304b is pulled out from the other of the circumferential ends of the wound portion 302 in the X direction. The first pull-out portion 304a and the second pull-out portion 304b are joined to each other by, for example, heat fusion. This forms a side sealing portion 530 when viewed from the front. The pull-out portion 304 is folded along the top surface of the battery element 100. However, the pull-out portion 304 does not have to be folded. The folding shape of the pull-out portion 304 is not limited to the shape described in the embodiment.

[0024] Fig. 4 is a rear view of the front lid member 210 according to the embodiment. The front lid member 210 will be described with reference to Fig. 4, and also with reference to Figs. 1 to 3 as necessary.

[0025] A front notch 210a is provided in the front cover member 210. The positive electrode tab 110 passes through the front notch 210a and is pulled out toward the front from the front cover member 210. Note that the position where the front notch 210a is provided is not limited to the example shown in FIG.

[0026] A rib 212 is provided on the rear surface of the front lid member 210. The rib 212 protrudes rearward from the rear surface of the front lid member 210. The rib 212 can function as a reinforcing material that reinforces the strength of the front lid member 210. Therefore, in the embodiment, compared to when the rib 212 is not provided, the thickness of the front lid member 210 in the X direction can be made thinner while ensuring the strength of the front lid member 210.

[0027] In the example shown in FIG. 4, the ribs 212 extend in a substantially rectangular lattice frame shape when viewed from the X direction. Therefore, spaces 212a are defined in the areas surrounded by the frames of the ribs 212 when viewed from the X direction. The spaces 212a are connected to the storage space 500. This allows excess electrolyte to be stored in the spaces 212a. This makes it easier to prevent performance degradation of the battery cell 10 due to depletion of electrolyte. This allows the battery cell 10 to have a longer life. Alternatively, the spaces 212a can store at least a portion of the positive electrode current collector 102a.

[0028] The position at which the rib 212 is provided is not limited to the example shown in Fig. 4. The rib 212 may be provided, for example, on the front surface of the front cover member 210. Furthermore, the shape of the rib 212 when viewed from the X direction is not limited to the example shown in Fig. 4.

[0029] The rear cover member 220 can also be provided with ribs in the same manner as the front cover member 210.

[0030] Next, an example of a method for manufacturing the battery cell 10 according to the embodiment will be described. In this example, the battery cell 10 is manufactured as follows.

[0031] First, the battery element 100 is manufactured. The battery element 100 has at least one positive electrode, at least one negative electrode, and at least one separator.

[0032] Next, the positive electrode tab 110 and the front cover member 210 are joined together. Similarly, the negative electrode tab 120 and the rear cover member 220 are joined together. Next, the positive electrode tab 110 and the positive electrode current collector 102a are joined together. Similarly, the negative electrode tab 120 and the negative electrode current collector 104a are joined together. However, the positive electrode tab 110 and the positive electrode current collector 102a may be joined together first, and then the positive electrode tab 110 and the front cover member 210 may be joined together. Similarly, the negative electrode tab 120 and the negative electrode current collector 104a may be joined together first, and then the negative electrode tab 120 and the rear cover member 220 may be joined together.

[0033] Next, the exterior film 300 is wrapped around the battery element 100, the front cover member 210, and the rear cover member 220 in the X direction once, thereby forming the wrapped portion 302. In addition, the excess length of the exterior film 300 is pulled out as the pulled-out portion 304.

[0034] Next, the outer peripheral surface of the front lid member 210 in the X direction and the inner peripheral surface of the front opening of the wound portion 302 in the X direction are joined together by heat fusion, thereby forming the front sealed portion 510. Next, the outer peripheral surface of the rear lid member 220 in the X direction and the inner peripheral surface of the rear opening of the wound portion 302 in the X direction are joined together by heat fusion, thereby forming the rear sealed portion 520.

[0035] Next, an electrolyte is injected into the accommodation space 500 through the gap between the first drawn portion 304a and the second drawn portion 304b. Next, the accommodation space 500 is evacuated through the gap between the first drawn portion 304a and the second drawn portion 304b. Next, the first drawn portion 304a and the second drawn portion 304b are joined by heat fusion to form the side sealing portion 530. This vacuum-seals the accommodation space 500.

[0036] The method for vacuum-sealing the storage space 500 is not limited to the above example. In another example, first, the first drawn-out portion 304a and the second drawn-out portion 304b are joined by heat fusion to form the side sealing portion 530. Next, electrolyte is injected into the storage space 500 through an injection hole provided in at least one of the front cover member 210 and the rear cover member 220. Next, a vacuum is drawn in the storage space 500 through the injection hole. Next, the injection hole is closed with a predetermined cover member.

[0037] Next, the side sealing portion 530 is folded along the top surface of the battery element 100 .

[0038] In this manner, the battery cell 10 is manufactured.

[0039] FIG. 5 is a side view of a portion of a battery cell 10A according to Modification 1. FIG. 6 is a rear view of a front cover member 210A according to Modification 1. In FIG. 5, a portion of the front cover member 210A is shown in a see-through manner for ease of explanation. In FIG. 5, the exterior film is not shown for ease of explanation. In FIG. 6, the rib 212A is not shown for ease of explanation. The battery cell 10A according to Modification 1 is similar to the battery cell 10 according to the embodiment, except for the following points. The matters described using FIG. 5 and FIG. 6 can be similarly applied to the rear cover member and the negative electrode tab.

[0040] As shown in FIG. 5, the front ends of the positive electrode current collectors 102aA and the rear end of the positive electrode tab 110A are joined to each other. The positive electrode current collectors 102aA are pulled out toward the front from the battery element 100A. The positive electrode current collectors 102aA are folded inside the front cover member 210A so as to overlap the battery element 100A in the X direction. The front ends of the positive electrode current collectors 102aA are approximately parallel to the Y direction. The front end of the positive electrode tab 110A is pulled out toward the front through the front notch 210aA of the front cover member 210A. The rear end of the positive electrode tab 110A is bent at a predetermined angle inside the front cover member 210A relative to the front end of the positive electrode tab 110A. Specifically, the rear end of the positive electrode tab 110A is bent at an approximately right angle to the front end of the positive electrode tab 110A inside the front cover member 210A when viewed from the Z direction. As a result, the rear end of the positive electrode tab 110A is approximately parallel to the Y direction. In Modification 1, the thickness of the front cover member 210A in the X direction can be made thinner than when the positive electrode current collector 102aA is not folded or when the rear end of the positive electrode tab 110A is not folded and is approximately parallel to the X direction. Therefore, in Modification 1, the volumetric energy density of the battery cell 10A can be more easily improved than when the positive electrode current collector 102aA is not folded or when the rear end of the positive electrode tab 110A is approximately parallel to the X direction.

[0041] As shown in FIG. 5, the protruding direction of the ribs 212A inside the front cover member 210A is approximately parallel to the X direction. The height in the X direction of the ribs 212A inside the front cover member 210A may vary depending on the position inside the front cover member 210A. For example, as shown in FIG. 6, the front cover member 210A has a central region 211aA and two side regions 211bA. The central region 211aA overlaps with the plurality of positive electrode current collectors 102aA and the positive electrode tabs 110A in the X direction. The two side regions 211bA are located on both sides of the central region 211aA in the Z direction. None of the side regions 211bA overlap with the plurality of positive electrode current collectors 102aA and the positive electrode tabs 110A in the X direction. The height in the X direction of the ribs 212A in each side region 211bA may be greater than the height in the X direction of the ribs 212A in the central region 211aA. In this case, the rib 212A may not be provided in the central region 211aA, but may be provided in each side region 211bA. This prevents the rib 212A from interfering with the multiple positive electrode current collectors 102aA and positive electrode tabs 110A in the central region 211aA. Furthermore, the height of the rib 212A in the X direction can be ensured in each side region 211bA.

[0042] In the first modification, at least a portion of the rib 212A may also define a space that communicates with the housing space that houses the battery element 100A.

[0043] In Modification 1, the plurality of positive electrode current collectors 102aA are folded in the region overlapping with the central region 211aA in the X direction. However, the plurality of positive electrode current collectors 102aA may not be folded in the region overlapping with the central region 211aA in the X direction but may simply be pulled out toward the front. In this example, the height in the X direction of the ribs 212A in each side region 211bA may be greater than the height in the X direction of the ribs 212A in the central region 211aA. In this case, the ribs 212A may not be provided in the central region 211aA, but may be provided in each side region 211bA. This prevents the ribs 212A from interfering with the plurality of positive electrode current collectors 102aA and the positive electrode tab 110A in the central region 211aA. Furthermore, the height in the X direction of the ribs 212A can be ensured in each side region 211bA.

[0044] FIG. 7 is a side view of a portion of a battery cell 10B according to Modification 2. For the sake of explanation, FIG. 7 shows a portion of the front cover member 210B as a see-through view. For ease of explanation, FIG. 7 does not show the exterior film. The battery cell 10B according to Modification 2 is similar to the battery cell 10A according to Modification 1, except for the following points. The matters described using FIG. 7 can also be applied to the rear cover member and negative electrode tab in the same way.

[0045] As shown in FIG. 7, the front ends of the positive electrode current collectors 102aB and the rear end of the positive electrode tab 110B are joined to each other. The positive electrode current collectors 102aB are pulled out forward from the battery element 100B. The positive electrode current collectors 102aB are folded inside the front cover member 210B so as to overlap the battery element 100B in the X direction. The front ends of the positive electrode current collectors 102aB are folded at a predetermined angle relative to the folded portions of the positive electrode current collectors 102aB. Specifically, the front ends of the positive electrode current collectors 102aB are folded at a substantially right angle relative to the folded portions of the positive electrode current collectors 102aB inside the front cover member 210B when viewed from the Z direction. As a result, the front ends of the positive electrode current collectors 102aB are substantially parallel to the X direction. The front end of the positive electrode tab 110B is pulled out toward the front through a front notch in the front cover member 210B. The rear end of the positive electrode tab 110B is not bent inside the front cover member 210B and is substantially parallel to the X direction. In Modification 2, the thickness of the front cover member 210B in the X direction can be made thinner than when the positive electrode current collector 102aB is not folded. Therefore, in Modification 2, it is easier to improve the volumetric energy density of the battery cell 10B than when the positive electrode current collector 102aB is not folded.

[0046] As shown in FIG. 7, the height of the rib 212B in the X direction may vary depending on the shape of the multiple positive electrode current collectors 102aB. In the example shown in FIG. 7, the height of the rib 212B in the X direction that overlaps with the folded portions of the multiple positive electrode current collectors 102aB in the X direction is greater than the height of the rib 212B in the X direction that overlaps with the folded portions of the multiple positive electrode current collectors 102aB that are substantially parallel to the X direction. In this case, the rib 212B may not be provided in the region that overlaps with the folded portions of the multiple positive electrode current collectors 102aB in the X direction, but may be provided in the region that overlaps with the folded portions of the multiple positive electrode current collectors 102aB in the X direction. This prevents the rib 212B from interfering with the front ends of the multiple positive electrode current collectors 102aB in the region that overlaps with the folded portions of the multiple positive electrode current collectors 102aB in the X direction. Furthermore, in the region overlapping with the folded portions of the plurality of positive electrode current collectors 102aB in the X direction, the height of the rib 212B in the X direction can be ensured.

[0047] In the second modification, at least a portion of the rib 212B may also define a space that communicates with the housing space that houses the battery element 100B.

[0048] Although the embodiments and modifications of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various configurations other than those described above can also be adopted.

[0049] In this embodiment, the positive electrode tab 110 and the negative electrode tab 120 are disposed on opposite sides of the battery element 100 in the X direction. However, both the positive electrode tab 110 and the negative electrode tab 120 may be disposed on only one of the front and rear sides of the battery element 100 in the X direction. In this case, the front and rear ends of the battery element 100 are covered, for example, by two lid materials. Alternatively, only the side of the battery element 100 from which the positive electrode tab 110 and the negative electrode tab 120 are pulled out may be covered by a lid material. In this example, an exterior film 300 may be sealed on the side of the battery element 100 opposite the lid material and folded along the battery element 100. [Explanation of symbols]

[0050] 10, 10A, 10B battery cells 100, 100A, 100B battery elements 102a,102aA,102aB Positive electrode current collector 104a Negative electrode current collector 110, 110A, 110B Positive tab 120 Negative electrode tab 210,210A,210B Front lid material 210a,210aA Front notch 211aA central area 211bA Lateral area 212, 212A, 212B Ribs 212a Space 220 Rear lid material 300 exterior film 302 Wrapping part 304 Drawer part 304a 1st drawer part 304b 2nd drawer part 500 storage spaces 510 Front sealing part 520 Rear sealing part 530 Side sealing part

Claims

1. A battery element; a lid member covering one end of the battery element; an exterior film at least partially wrapped around the battery element; A rib provided on the lid material; a current collector having a folded portion folded inside the lid member and a bent portion bent relative to the folded portion, the current collector being drawn out from the battery element; Equipped with a height of the rib in a region overlapping the folded portion of the current collector in the protruding direction of the rib is greater than a height of the rib in a region overlapping the folded portion of the current collector in the protruding direction of the rib.

2. A battery element; a lid member covering one end of the battery element; an exterior film at least partially wrapped around the battery element; A rib provided on the lid material; a current collector having a folded portion folded inside the lid member and a bent portion bent relative to the folded portion, the current collector being drawn out from the battery element; Equipped with the rib is provided in a region overlapping the folded portion of the current collector in a protruding direction of the rib, The battery cell, wherein the rib is not provided in an area that overlaps with the bent portion of the current collector in the protruding direction of the rib.

3. The battery cell according to claim 1 or 2, wherein at least a portion of the rib defines a space that communicates with an accommodation space formed by the lid material and the exterior film.

Images