Secondary cell and energy storage device

Abstract

The utility model relates to the technical field of batteries, and discloses a secondary battery monomer and an energy storage device. The secondary battery monomer comprises a plurality of roll cores, a positive electrode collector plate and a negative electrode collector plate; the multiple roll cores are arranged in the width direction and the thickness direction of the roll cores. A positive pole lug and a negative pole lug are arranged on one winding end face of the winding core, and the pole lugs with the same polarity are arranged on the same side in the thickness direction of the winding core; the positive collector plate is conductively connected with the positive tabs; the negative collector plate is conductively connected with each negative tab; the positive collector plate and the negative collector plate are both of U-shaped structures, and openings of the positive collector plate and the negative collector plate are oppositely arranged. According to the utility model, the problem of local lithium precipitation caused by non-uniform electrolyte infiltration of the roll core in the middle can be solved; the infiltration of electrolyte is facilitated; heat accumulation is reduced, heat dissipation is facilitated, and potential safety hazards are reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a secondary battery monomer and an energy storage device. Background Art

[0002] Secondary batteries such as lithium-ion batteries, solid electrolyte batteries, and sodium-ion batteries are widely used in 3C, power, and energy storage fields. When the gram capacity of active materials reaches a bottleneck, increasing the volume of single cells to reduce the utilization of ineffective space under the same volume has become an effective means to increase energy density.

[0003] Taking the winding process as an example, the current mainstream of multi-core stacking in large batteries is double-core and four-core longitudinal stacking. Large-scale winding secondary batteries are mostly realized by connecting two or four cores in parallel internally, which has the following technical problems:

[0004] 1. The thickness of the vertical stack increases, and the electrolyte infiltration in the middle core is uneven, which can easily cause local lithium precipitation problems;

[0005] 2. Stacking along the thickness is prone to heat accumulation, which makes heat dissipation difficult and poses a safety hazard. Utility Model Content

[0006] In view of this, the utility model provides a secondary battery cell and an energy storage device to solve at least one technical problem of uneven electrolyte infiltration or difficult heat dissipation in the thickness direction.

[0007] In the first aspect, the utility model provides a secondary battery cell, including a plurality of winding cores and a positive current collector plate and a negative current collector plate. The plurality of winding cores are arranged along the width direction and thickness direction of the winding cores; a winding end face of the winding core is provided with a positive electrode tab and a negative electrode tab, and the tabs of the same polarity are arranged on the same side along the thickness direction of the winding core; the positive current collector plate is conductively connected to each positive electrode tab; the negative current collector plate is conductively connected to each negative electrode tab; both the positive current collector plate and the negative current collector plate are U-shaped structures, and the openings of the positive current collector plate and the negative current collector plate are arranged facing each other.

[0008] Beneficial effect: The secondary battery cell provided by the utility model has multiple winding cores arranged in two directions, namely, the width direction and the thickness direction of the winding core, which can reduce the stacking thickness along the thickness direction of the winding core. Thus, the problem of local lithium precipitation caused by uneven electrolyte infiltration in the middle winding core can be solved. The winding core arrangement of the secondary battery cell of this embodiment is more conducive to the infiltration of the electrolyte. In addition, since the stacking thickness along the thickness direction of the winding core is reduced, the heat generation problem is alleviated to a certain extent, heat accumulation is reduced, heat dissipation is facilitated, and safety hazards are reduced. In addition, since the secondary battery cell provided by the utility model adopts a U-shaped structure for the current collecting plate, the problem of connecting the pole ears of double-row stacked cells is solved by conductively connecting the pole ears to the current collecting plate, the bending path of the pole ears can be shortened, and the rate and safety performance can be improved.

[0009] In an optional embodiment, the positive electrode current collector is provided with a plurality of first mounting holes for the positive electrode tabs to pass through, the positive electrode tabs pass through the first mounting holes and form at least one first bent portion, and the first bent portion is welded to the positive electrode current collector;

[0010] And / or, the negative electrode current collecting plate is provided with a plurality of second mounting holes for the negative electrode tabs to pass through, the negative electrode tabs pass through the second mounting holes and form at least one second bent portion, and the second bent portion is welded to the negative electrode current collecting plate.

[0011] In an optional embodiment, the positive electrode current collecting plate includes two first side plates arranged opposite to each other and a first middle plate connecting the two first side plates; the positive electrode tabs located on the same side in the thickness direction are connected through the first side plates, and the positive electrode tabs located on the same side in the width direction are connected through the first middle plate;

[0012] And / or, the negative electrode current collecting plate includes two oppositely arranged second side plates and a second middle plate connecting the two second side plates; the negative electrode tabs located on the same side along the thickness direction are connected through the second side plates, and the negative electrode tabs located on the same side along the width direction are connected through the second middle plate.

[0013] In an optional embodiment, the first middle plate is provided with a protruding positive pole, and the second middle plate is provided with a protruding negative pole, and the positive pole and the negative pole are both close to or located at the junction of the adjacent winding cores along the width direction.

[0014] In an optional embodiment, a fuse zone is provided at least at one of the two ends of the first middle plate, and the width of the fuse zone is smaller than the width of the surrounding area thereof.

[0015] In an optional embodiment, an insulating layer is provided on one side of the positive electrode current collecting plate close to the winding core and one side of the negative electrode current collecting plate close to the winding core.

[0016] In an optional embodiment, an injection gap is formed between four adjacent winding cores along the width and thickness directions of the winding core; the secondary battery cell also includes a cover plate assembly, which is provided with at least one injection hole, and the projection of the injection hole is located within the injection gap along the length direction of the winding core.

[0017] In an optional embodiment, the cover plate assembly further includes two or more explosion-proof valves, which are spaced apart and distributed on both sides of the line connecting the positive electrode column and the negative electrode column.

[0018] In an optional embodiment, the cover plate assembly is provided with a positive pole mounting hole and a negative pole mounting hole, the positive pole passes through the positive pole mounting hole and is insulated and sealedly connected to the cover plate assembly, and the negative pole passes through the negative pole mounting hole and is insulated and sealedly connected to the cover plate assembly.

[0019] In a second aspect, the utility model further provides an energy storage device, comprising a secondary battery cell of any one of the above technical solutions.

[0020] Beneficial effects: Since the energy storage device includes a secondary battery cell, it has the same effects as the secondary battery cell, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 This is a schematic diagram of the structure of a winding core in a secondary battery cell according to an embodiment of the utility model;

[0023] Figure 2 It is a schematic diagram of the structure before the pole ear is connected to the current collecting plate;

[0024] Figure 3 It is a schematic diagram of the structure after the pole ear is connected to the current collecting plate;

[0025] Figure 4 It is a schematic diagram of the exploded structure of the winding core and the cover plate assembly;

[0026] Figure 5 It is a schematic diagram of the overall structure of a secondary battery cell according to an embodiment of the utility model.

[0027] Description of reference numerals:

[0028] 1. Winding core; 11. Positive electrode ear; 12. Negative electrode ear; 21. Positive current collecting plate; 211. First side plate; 212. First middle plate; 2121. Fuse zone; 22. Negative current collecting plate; 221. Second side plate; 222. Second middle plate; 31. First mounting hole; 32. Second mounting hole; 41. First bending portion; 42. Second bending portion; 51. Positive pole; 52. Negative pole; 61. Positive pole mounting hole; 62. Negative pole mounting hole; 2. Liquid injection gap; 3. Liquid injection hole; 4. Explosion-proof valve; 5. Cover plate; 6. Insulating plate; 7. Column cap; 8. Sealing ring. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0030] Combine the following Figures 1 to 5 , describing an embodiment of the utility model.

[0031] According to an embodiment of the utility model, on the one hand, a secondary battery cell is provided, including a plurality of winding cores 1, and a positive current collecting plate 21 and a negative current collecting plate 22. The plurality of winding cores 1 are arranged along the width direction and the thickness direction of the winding core 1; a positive electrode tab 11 and a negative electrode tab 12 are provided on one winding end face of the winding core 1, and the tabs of the same polarity are arranged on the same side along the thickness direction of the winding core 1; the positive current collecting plate 21 is conductively connected to each positive electrode tab 11; the negative current collecting plate 22 is conductively connected to each negative electrode tab 12, and both the positive current collecting plate 21 and the negative current collecting plate 22 are U-shaped structures, and the openings of the positive current collecting plate 21 and the negative current collecting plate 22 are arranged facing each other.

[0032] The secondary battery cell provided by the embodiment of the utility model has multiple winding cores 1 arranged in two directions, the width direction and the thickness direction of the winding core 1, which can reduce the stacking thickness along the thickness direction of the winding core 1. Thus, the problem of local lithium precipitation caused by uneven electrolyte infiltration in the middle winding core 1 can be solved. The arrangement of the winding core 1 of the secondary battery cell of this embodiment is more conducive to the infiltration of the electrolyte. In addition, since the stacking thickness along the thickness direction of the winding core 1 is reduced, the heat generation problem is alleviated to a certain extent, heat accumulation is reduced, heat dissipation is beneficial, and safety hazards are reduced.

[0033] In addition, since the current collecting plate of the secondary battery cell provided in this embodiment adopts a U-shaped structure, the problem of connecting the pole tabs of double-row stacked cells is solved by conductively connecting the pole tabs to the current collecting plate, which can shorten the bending path of the pole tabs and improve the rate and safety performance.

[0034] Specifically, in some embodiments, the end surface of the winding core 1 is approximately elliptical, and the width direction of the winding core 1 refers to the direction in which the major axis of the ellipse extends. Figure 1 The thickness direction of the core 1 refers to the direction in which the minor axis of the ellipse extends. Figure 1 The length direction of the core 1 is shown in the Y direction. Figure 1 In the paper, it is represented as a direction perpendicular to the paper surface.

[0035] In one embodiment, Figure 1 As shown, the secondary battery cell includes six winding cores 1 , three winding cores 1 are stacked in the thickness direction, and two rows are arranged in the width direction of the winding cores 1 , that is, arranged in a 3×2 manner.

[0036] In one embodiment, the positive current collecting plate 21 is provided with a plurality of first mounting holes 31 for the positive electrode tabs 11 to pass through. The positive electrode tabs 11 pass through the first mounting holes 31 and form at least one first bending portion 41 . The first bending portion 41 is welded to the positive current collecting plate 21 .

[0037] like Figure 2 As shown, after the positive electrode tab 11 passes through the first mounting hole 31 of the positive electrode current collecting plate 21 , two first bent portions 41 are formed. The two first bent portions 41 are folded in opposite directions respectively, and the two first bent portions 41 are welded to the positive electrode current collecting plate 21 .

[0038] In one embodiment, the negative electrode current collecting plate 22 is provided with a plurality of second mounting holes 32 for the negative electrode tabs 12 to pass through. The negative electrode tabs 12 pass through the second mounting holes 32 and form at least one second bent portion 42 . The second bent portion 42 is welded to the negative electrode current collecting plate 22 .

[0039] The connection method between the negative electrode current collector 22 and the negative electrode tab 12 can be the same as that on the positive electrode side, such as Figure 2 shown.

[0040] Compared with the traditional form of bending the pole ear and welding the adapter plate, this embodiment adopts this connection method between the pole ear and the current collecting plate, which can shorten the bending path of the pole ear, reduce the risk of short circuit between the burrs on the edge of the pole ear and the pole piece, and at the same time shorten the transmission path of electrons to improve the rate performance.

[0041] In one embodiment, the positive electrode current collecting plate 21 includes two oppositely arranged first side plates 211 and a first middle plate 212 connecting the two first side plates 211, and the positive electrode tabs 11 located on the same side along the thickness direction are connected through the first side plates 211, and the positive electrode tabs 11 located on the same side along the width direction are connected through the first middle plate 212.

[0042] In one embodiment, the negative electrode current collecting plate 22 includes two oppositely arranged second side plates 221 and a second middle plate 222 connecting the two second side plates 221, and the negative electrode tabs 12 located on the same side along the thickness direction are connected through the second side plates 221, and the negative electrode tabs 12 located on the same side along the width direction are connected through the second middle plate 222.

[0043] like Figure 1 As shown, in this embodiment, when two rows of winding cores 1 are arranged along the width direction, the positive electrode tabs 11 of the two rows of winding cores 1 are arranged adjacent to each other, that is, Figure 1 In the overall structure of the winding core 1 shown, the positive electrode tab 11 is located inside, and the negative electrode tab 12 is located outside.

[0044] In one embodiment, the first middle plate 212 is provided with a protruding positive electrode column 51, and the second middle plate 222 is provided with a protruding negative electrode column 52, and the positive electrode column 51 and the negative electrode column 52 are both close to or located at the junction of the adjacent winding cores 1 along the width direction. In this way, the performance of the battery can be guaranteed.

[0045] In one embodiment, a fuse zone 2121 is disposed at at least one of the two ends of the first middle plate 212 , and the width of the fuse zone 2121 is smaller than the width of the surrounding area thereof.

[0046] By setting the fuse area 2121 on the positive current collecting plate 21 as an overcurrent fuse point, a safety protection function is achieved. In this embodiment, fuse areas 2121 are set at both ends of the first middle plate 212 of the positive current collecting plate 21, which can further improve the safety protection function.

[0047] Specifically, since the width of the fuse region 2121 is smaller than the width of its surrounding area, that is, a groove structure can be provided at the corner where the first middle plate 212 of the positive electrode current collecting plate 21 is connected to the first side plate 211 .

[0048] In one embodiment, an insulating layer is provided on one side of the positive electrode current collecting plate 21 close to the winding core 1 and on one side of the negative electrode current collecting plate 22 close to the winding core 1 .

[0049] By providing an insulating layer on one side of the current collector plate close to the winding core, it is possible to prevent the current collector plate from short-circuiting with the end surface of the winding core 1. The insulating layer can be formed by coating an insulating material on the current collector plate, and the insulating material includes but is not limited to polymer resin or ceramic.

[0050] In one embodiment, a liquid injection gap 2 that is conducive to liquid injection is formed between four adjacent cores 1 along the width and thickness directions of the core 1; the secondary battery cell also includes a cover plate assembly, which is provided with at least one liquid injection hole 3, and the projection of the liquid injection hole 3 is located within the liquid injection gap 2 along the length direction of the core 1.

[0051] Such an arrangement can increase the injection rate and improve the efficiency of the injection section.

[0052] Furthermore, in some embodiments, the injection hole 3 is located on the connecting line of the positive electrode column 51 and the negative electrode column 52 .

[0053] In one embodiment, Figure 4 As shown, six winding cores 1 form two liquid injection gaps 2 in total, and two liquid injection holes 3 are provided. Along the length direction of the winding core 1, the projections of the two liquid injection holes 3 are respectively located in the two liquid injection gaps 2.

[0054] The corresponding double injection holes 3 are opened at the upper part of the injection gap 2 formed by the winding core 1, which can increase the injection rate.

[0055] In one embodiment, the cover plate assembly further includes two or more explosion-proof valves 4 , which are spaced apart and distributed on both sides of the line connecting the positive electrode column 51 and the negative electrode column 52 .

[0056] In this arrangement, the opening side of the explosion-proof valve 4 is located between the two rows of stacked battery cells. During the gas production process of the battery cells, the gas flows upward and the diffusion path is short, so the valve can be opened in time to prevent thermal runaway. An explosion-proof valve 4 is opened on the upper part of each of the two rows of winding cores 1, so that the valve can be opened quickly during abnormal gas production of the battery cells, thereby improving the safety performance of the battery cells.

[0057] In one embodiment, the cover plate assembly is provided with a positive pole mounting hole 61 and a negative pole mounting hole 62, the positive pole 51 passes through the positive pole mounting hole 61 and is insulated and sealedly connected to the cover plate assembly, and the negative pole 52 passes through the negative pole mounting hole 62 and is insulated and sealedly connected to the cover plate assembly.

[0058] Specifically, a sealing ring 8 is sleeved on the positive pole 51 and the negative pole 52, and the positive pole 51 and the negative pole 52 are respectively sealed and connected to the cover assembly. The positive current collector 21 is electrically connected to the positive pole 51, and the negative current collector 22 is electrically connected to the negative pole 52.

[0059] In one embodiment, the cover plate assembly includes a cover plate 5 and an insulating plate 6, and the positive pole mounting hole 61 and the negative pole mounting hole 62 both penetrate the cover plate 5 and the insulating plate 6; the pole mounting hole of the cover plate 5 is also provided with a hollow pole cap 7. After the positive pole 51 passes through the positive pole mounting hole 61, it is inserted into the pole cap 7 and welded to the pole cap 7. The same is true for the negative pole.

[0060] According to an embodiment of the present invention, on the other hand, there is provided an energy storage device, comprising the secondary battery cell described in any one of the above embodiments.

[0061] Since the energy storage device includes a secondary battery cell and has the same effect as the secondary battery cell, it will not be described in detail here.

[0062] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A secondary battery cell, characterized in that: include: A plurality of winding cores (1), wherein the plurality of winding cores (1) are arranged in a width direction and a thickness direction of the winding core (1); A winding end surface of the winding core (1) is provided with a positive electrode tab (11) and a negative electrode tab (12), and along the thickness direction of the winding core (1), the tabs of the same polarity are arranged on the same side; A positive electrode current collecting plate (21), the positive electrode current collecting plate (21) and each of the positive electrode tabs (11) being electrically connected; A negative electrode current collecting plate (22), the negative electrode current collecting plate (22) and each of the negative electrode tabs (12) being electrically connected; The positive electrode current collecting plate (21) and the negative electrode current collecting plate (22) are both U-shaped structures, and the openings of the positive electrode current collecting plate (21) and the openings of the negative electrode current collecting plate (22) are arranged facing each other.

2. The secondary battery cell according to claim 1, characterized in that: The positive electrode current collecting plate (21) is provided with a plurality of first mounting holes (31) for the positive electrode tabs (11) to pass through, the positive electrode tabs (11) pass through the first mounting holes (31) and form at least one first bent portion (41), and the first bent portion (41) is welded to the positive electrode current collecting plate (21); And / or, the negative electrode current collector plate (22) is provided with a plurality of second mounting holes (32) for the negative electrode tab (12) to pass through, the negative electrode tab (12) passes through the second mounting holes (32) and forms at least one second bent portion (42), and the second bent portion (42) is welded to the negative electrode current collector plate (22).

3. The secondary battery cell according to claim 1 or 2, characterized in that: The positive electrode current collecting plate (21) comprises two first side plates (211) arranged opposite to each other and a first middle plate (212) connecting the two first side plates (211); the positive electrode tabs (11) located on the same side in the thickness direction are connected via the first side plates (211), and the positive electrode tabs (11) located on the same side in the width direction are connected via the first middle plate (212); And / or, the negative electrode current collecting plate (22) comprises two second side plates (221) arranged opposite to each other and a second middle plate (222) connecting the two second side plates (221); the negative electrode tabs (12) located on the same side in the thickness direction are connected via the second side plates (221), and the negative electrode tabs (12) located on the same side in the width direction are connected via the second middle plate (222).

4. The secondary battery cell according to claim 3, characterized in that: The first middle plate (212) is provided with a protruding positive pole (51), and the second middle plate (222) is provided with a protruding negative pole (52), and the positive pole (51) and the negative pole (52) are both close to or located at the junction of the adjacent winding cores (1) in the width direction.

5. The secondary battery cell according to claim 3, characterized in that: At least one of the two ends of the first middle plate (212) is provided with a fuse zone (2121), and the width of the fuse zone (2121) is smaller than the width of its surrounding area.

6. The secondary battery cell according to claim 3, characterized in that: A side of the positive electrode current collecting plate (21) close to the winding core (1) and a side of the negative electrode current collecting plate (22) close to the winding core (1) are both provided with an insulating layer.

7. The secondary battery cell according to claim 4, characterized in that: A liquid injection gap (2) is formed between four adjacent winding cores (1) along the width direction and the thickness direction of the winding core (1); the secondary battery cell also includes a cover plate assembly, the cover plate assembly is provided with at least one liquid injection hole (3), and along the length direction of the winding core (1), the projection of the liquid injection hole (3) is located in the liquid injection gap (2).

8. The secondary battery cell according to claim 7, characterized in that: The cover plate assembly further comprises two or more explosion-proof valves (4), wherein the explosion-proof valves (4) are distributed at intervals on both sides of a line connecting the positive electrode column (51) and the negative electrode column (52).

9. The secondary battery cell according to claim 7, characterized in that: The cover plate assembly is provided with a positive pole column mounting hole (61) and a negative pole column mounting hole (62); the positive pole column (51) passes through the positive pole column mounting hole (61) and is insulated and sealedly connected to the cover plate assembly; the negative pole column (52) passes through the negative pole column mounting hole (62) and is insulated and sealedly connected to the cover plate assembly.

10. An energy storage device, characterized in that: The invention comprises the secondary battery cell according to any one of claims 1 to 9.

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