Battery cell pole group and single battery cell

Abstract

The utility model belongs to the technical field of battery cells, and discloses a battery cell pole group and a single battery cell, the battery cell pole group comprises a tab and a connecting piece, the tab comprises a plurality of diversion parts, metal layers on two sides of each composite current collector body are connected with the diversion parts, the diversion parts on the multiple layers of composite current collector pole pieces are distributed in a staggered manner, and the connecting piece is connected with the connecting piece. The connecting piece is used for forming two diversion dislocation areas and an overlapping area on the tab, the connecting piece comprises branch parts and a connecting main body part, one side of the connecting main body part is connected with the branch parts which are in one-to-one correspondence with the two diversion dislocation areas, and the two branch parts are arranged at an interval and are respectively connected to the respective corresponding diversion dislocation areas; the connecting main body part is used for being connected with a battery cell cover plate; therefore, conduction of the metal layers on the two sides of the single composite current collector body is achieved, series connection of multiple layers of composite current collector pole pieces is achieved, the welding levels are reduced, the welding workload is reduced, the production time is shortened, and the risk that current conduction is not smooth due to poor welding is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of battery cells, in particular to a battery cell electrode group and a single battery cell. Background Art

[0002] With the popularization of electric vehicles, people have put forward higher and higher requirements for the energy density and safety performance of lithium-ion batteries. The composite current collector material with a polymer layer in the middle and metal layers on both sides has low density and high safety performance. Therefore, the electrode sheet made of the composite current collector material has better effects.

[0003] However, since the middle of the composite current collector is polymer, the metal layers on both sides of the polymer cannot achieve current conduction with each other. At present, a separate adapter piece is needed to connect the metal layers on both sides of the composite current collector. After that, the adapter pieces on the multi-layer composite current collectors are connected together through connecting pieces, and then the tab is connected to the connecting piece to complete the series connection of multiple electrode sheets. Finally, the tab is connected to the battery cell cover plate to complete the current conduction.

[0004] Among them, the multi-level connection not only leads to a large amount of welding operations, wastes a lot of time, reduces production efficiency, but also increases the risk of unsmooth current conduction due to poor welding because of the large number of welding levels, reducing the product quality. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a battery cell electrode group and a single battery cell, which reduce the amount of welding operations, shorten the production time, improve the production efficiency, reduce the risk of unsmooth current conduction due to poor welding, and improve the product quality.

[0006] To achieve the above object, the utility model adopts the following technical solutions:

[0007] On the one hand, a battery cell electrode group is provided. The battery cell electrode group includes a multi-layer composite current collector electrode sheet and a separator disposed between two adjacent composite current collector electrode sheets. The composite current collector electrode sheet includes a composite current collector body and an electrode material coating coated on the composite current collector body. The battery cell electrode group further includes:

[0008] Tabs, each tab includes a plurality of current guiding members. The metal layers on both sides of each composite current collector body are connected with the current guiding members. The current guiding members on the multi-layer composite current collector electrode sheets are distributed in a staggered manner to form two current guiding staggered areas and an overlapping area on the tab. The two current guiding staggered areas are located on both sides of the overlapping area along the first direction;

[0009] A connecting piece, the connecting piece includes a branched portion and a connecting main body portion, one side of the connecting main body portion is connected with the branched portions corresponding to the two diversion misalignment regions one by one, the two branched portions are arranged at intervals and are respectively connected to the corresponding diversion misalignment regions, and the connecting main body portion is used for connecting with the cell cover plate.

[0010] Optionally, the connecting main body portion further includes a welding area and a bending area, the bending area is arranged on the side of the welding area facing the branched portion, and the welding area is used for connecting with the cell cover plate.

[0011] Optionally, the height dimension of the bending area in the second direction is A, and 0mm < A ≤ 10mm is satisfied.

[0012] Optionally, the height dimension of the welding area in the second direction is B, and 1mm < B ≤ 100mm is satisfied.

[0013] Optionally, the length dimension of the branched portion in the first direction is C, and n×d ≤ C ≤ D is satisfied, where n is the number of the diversion members constituting a single tab, d is the misalignment distance dimension between two adjacent diversion members, and D is the length dimension of the connecting piece in the first direction.

[0014] Optionally, the length dimension D of the connecting piece in the first direction satisfies E + n×d ≤ D ≤ F / 2, where E is the length dimension of the overlapping area in the first direction, and F is the length dimension of the composite current collector pole piece in the first direction.

[0015] Optionally, the number n of the diversion members constituting a single tab satisfies 0 < n ≤ (F - E) / d.

[0016] Optionally, the length dimension E of the overlapping area in the first direction satisfies F / 20 ≤ E ≤ F / 2.

[0017] Optionally, the height dimension H of the tab in the second direction satisfies 0mm < H ≤ 100mm.

[0018] On the other hand, a single cell is provided, the single cell includes the cell pole group as described in any one of the above, the single cell further includes a housing and the cell cover plate, and the cell cover plate is covered on the housing to construct a chamber for accommodating the cell pole group.

[0019] Advantages of the present utility model:

[0020] The present utility model provides a battery cell electrode group. In this battery cell electrode group, current collectors for forming tabs are connected to the metal layers on both sides of the composite current collector body, and the current collectors on the multi-layer composite current collector electrodes are arranged in a staggered manner, so as to form two current collection staggered areas and an overlapping area on the tabs. The branch parts on the connecting piece corresponding to the current collection staggered areas are respectively connected to their corresponding current collection staggered areas, thereby realizing the conduction of the metal layers on both sides of a single composite current collector body and the series connection of the multi-layer composite current collector electrodes. As a result, the number of welding layers is reduced, the welding workload is decreased, the production time is shortened, the production efficiency is improved, the risk of unsmooth current conduction due to poor welding is reduced, and the product quality is improved.

[0021] The present utility model also provides a single battery cell. By applying the above-mentioned battery cell electrode group, the production cycle is shortened, the production output is increased, and the product quality is improved. Description of the Drawings

[0022] Figure 1 is a schematic structural diagram of the connecting piece in the battery cell electrode group provided by the present utility model;

[0023] Figure 2 is a schematic connection diagram of the connecting piece and the composite current collector electrode in the battery cell electrode group provided by the present utility model;

[0024] Figure 3 is a schematic structural diagram of the battery cell electrode group provided by the present utility model before assembling the connecting piece;

[0025] Figure 4 is a schematic connection diagram of the positive tab and the composite current collector electrode in the battery cell electrode group provided by the present utility model;

[0026] Figure 5 is a schematic connection diagram of the negative tab and the composite current collector electrode in the battery cell electrode group provided by the present utility model;

[0027] Figure 6 is a schematic diagram of the distribution state of multiple current collectors in the battery cell electrode group provided by the present utility model.

[0028] In the figure:

[0029] 100, composite current collector electrode;

[0030] 1, positive tab;

[0031] 2, negative tab;

[0032] 3, current collector;

[0033] 4, current collection staggered area;

[0034] 5, overlapping area;

[0035] 6. Connecting piece; 61. Branch portion; 62. Connecting main body portion; 621. Welding area; 622. Bending area. Detailed implementation manner

[0036] The present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present utility model, rather than limiting the present utility model. In addition, it should be noted that, for the sake of convenience of description, only parts related to the present utility model are shown in the drawings, rather than all structures.

[0037] In the description of the present utility model, unless otherwise clearly defined and limited, the terms "connected", "connected", and "fixed" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0038] In the present utility model, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "above", and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "below", and "under" the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicating that the horizontal height of the first feature is lower than that of the second feature.

[0039] In the description of this embodiment, the orientation or positional relationships such as "above", "below", "right", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present utility model. In addition, the terms "first" and "second" are only used for differentiation in description and have no special meanings.

[0040] With the popularization of electric vehicles, people have put forward higher and higher requirements for the energy density and safety performance of lithium-ion batteries. The composite current collector material with a polymer layer in the middle and metal layers on both sides has a light density and high safety performance. Therefore, the pole piece made of the composite current collector material has better effects.

[0041] However, since the composite current collector has a polymer in the middle, the metal layers on both sides of the polymer cannot conduct current with each other. Currently, a separate adapter is needed to connect the metal layers on both sides of the composite current collector. After that, the adapters on the multi-layer composite current collectors are connected together through connecting pieces, and then the tab is connected to the connecting piece to complete the series connection of multiple electrode plates. Finally, the tab is connected to the cell cover plate to complete the current conduction.

[0042] Among them, the multi-level connection not only causes a large number of welding operations, resulting in a waste of a lot of time and reducing production efficiency, but also increases the risk of unsmooth current conduction due to poor welding due to the large number of welding levels, reducing the product quality.

[0043] Therefore, in order to reduce the amount of welding work, shorten the production time, improve production efficiency, reduce the risk of unsmooth current conduction due to poor welding, and improve product quality, this embodiment provides a cell pole group, which includes multi-layer composite current collector electrode plates and a separator disposed between two adjacent composite current collector electrode plates. The composite current collector electrode plate includes a composite current collector body and an electrode material coating coated on the composite current collector body.

[0044] As Figures 1 to 6 shown, the cell pole group includes a tab and a connecting piece 6. The tab includes a plurality of current guiding members 3. The metal layers on both sides of each composite current collector body are connected with a current guiding member 3. The current guiding members 3 on the multi-layer composite current collector electrode plates 100 are staggeredly distributed to form two current guiding staggered areas 4 and an overlapping area 5 on the tab. The two current guiding staggered areas 4 are located on both sides of the overlapping area 5 along the first direction. The connecting piece 6 includes a branch portion 61 and a connecting main body portion 62. One side of the connecting main body portion 62 is connected with branch portions 61 corresponding to the two current guiding staggered areas 4 one by one. The two branch portions 61 are spaced apart and are respectively connected to their corresponding current guiding staggered areas 4. The connecting main body portion 62 is used to connect with the cell cover plate.

[0045] The cell pole group connects the current guiding members 3 used to form the tab to the metal layers on both sides of the composite current collector body, and makes the current guiding members 3 on the multi-layer composite current collector electrode plates 100 staggeredly distributed, so as to form two current guiding staggered areas 4 and an overlapping area 5 on the tab, and makes the branch portions 61 corresponding to the current guiding staggered areas 4 on the connecting piece 6 be respectively connected to their corresponding current guiding staggered areas 4, so as to not only realize the conduction of the metal layers on both sides of a single composite current collector body, but also realize the series connection of the multi-layer composite current collector electrode plates 100, thereby reducing the welding levels, reducing the amount of welding work, shortening the production time, improving the production efficiency, reducing the risk of unsmooth current conduction due to poor welding, and improving the product quality.

[0046] Among them, the cell electrode group can be used in various different types of single cells, such as blade batteries or square shell batteries. In a blade battery, the cell electrode group adopts the method of leading out electrode tabs on both sides. In a square shell battery, the cell electrode group adopts the method of leading out electrode tabs on the same side. The electrode tabs of the cell electrode group are divided into a positive electrode tab 1 and a negative electrode tab 2 according to the different polarities of the composite current collector electrode sheet 100 they are connected to. In this embodiment, the cell electrode group is applied in a square shell battery and adopts the method of leading out electrode tabs on the same side, and the positive electrode tab 1 and the negative electrode tab 2 are located on the same side.

[0047] Optionally, as Figure 1 shown, the connection main body portion 62 further includes a welding area 621 and a bending area 622. The bending area 622 is provided on the side of the welding area 621 facing the branch portion 61. The welding area 621 is used to connect with the cell cover plate. By providing the welding area 621 and the bending area 622 on the connection main body portion 62, on the one hand, it is convenient to bend the connection piece 6 during shell insertion, facilitating assembly. On the other hand, the welding area 621 is provided on the side of the bending area 622 away from the branch portion 61, and the bending area 622 is used to separate the welding area 621 and the branch portion 61, thereby avoiding interference during welding.

[0048] Furthermore, as Figure 1 shown, the height dimension of the bending area 622 in the second direction is A, and 0mm < A ≤ 10mm is satisfied. By limiting the height dimension A of the bending area 622 in the second direction, it is ensured that the interval between the welding area 621 and the branch portion 61 meets the requirements, and interference between the welding area 621 and the branch portion 61 during welding is avoided. The height dimension A of the bending area 622 in the second direction can be any value or the range between any two values within 0mm < A ≤ 10mm, such as 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc.

[0049] Optionally, as Figure 1 shown, the height dimension of the welding area 621 in the second direction is B, and 1mm < B ≤ 100mm is satisfied. By limiting the height dimension B of the welding area 621 in the second direction, it is ensured that the welding area 621 has a sufficient welding area with the cell cover plate. On the one hand, it is convenient for the two to carry out welding operations. On the other hand, the firmness and welding quality of the welding are ensured. The height dimension B of the welding area 621 in the second direction can be any value or the range between any two values within 1mm < B ≤ 100mm, such as 10mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, etc.

[0050] Optionally, as Figure 1As shown, the length dimension of the branch portion 61 in the first direction is C, and it satisfies n×d≤C≤D, where n is the number of current-conducting members 3 that make up a single tab, d is the misalignment spacing dimension between two adjacent current-conducting members 3, and D is the length dimension of the connecting piece 6 in the first direction. By limiting the length dimension C of the branch portion 61 in the first direction to satisfy n×d≤C≤D, it is ensured that the branch portion 61 has sufficient length, thereby achieving coverage of the current-conducting misalignment area 4 and avoiding areas in the current-conducting misalignment area 4 that cannot be welded to the branch portion 61 due to insufficient length of the branch portion 61. In this embodiment, the length dimensions C of the two branch portions 61 on the same connecting piece 6 in the first direction are equal.

[0051] In this embodiment, since the battery cell pole group has a positive tab 1 and a negative tab 2, the connecting piece 6 is provided with a corresponding positive connecting piece and a negative connecting piece. Therefore, the length dimension of the positive connecting piece in the first direction is D1, and the length dimension of the negative connecting piece in the first direction is D2. Since the conductivity of the positive electrode material and the conductivity of the negative electrode material are different, there are certain differences in the sizes of the positive tab 1 and the negative tab 2. Therefore, there are differences in the number of current-conducting members 3 that make up the positive tab 1 and the negative tab 2. At this time, the number of current-conducting members 3 that make up the positive tab 1 is n1, and the number of current-conducting members 3 that make up the negative tab 2 is n2. And because the sizes of the positive tab 1 and the negative tab 2 are different, the misalignment spacing dimension between two adjacent current-conducting members 3 that make up the positive tab 1 is d1, and the misalignment spacing dimension between two adjacent current-conducting members 3 that make up the negative tab 2 is d2. Therefore, the length C of the branch portion 61 of the positive connecting piece connected to the positive tab 1 in the first direction satisfies n1×d1≤C≤D1, and the length C of the branch portion 61 of the negative connecting piece connected to the negative tab 2 in the first direction satisfies n2×d2≤C≤D2.

[0052] Optionally, as Figure 1 、 Figure 3 shown, the length dimension D of the connecting piece 6 in the first direction satisfies E + n×d≤D≤F / 2, where E is the length dimension of the overlapping area 5 in the first direction, and F is the length dimension of the composite current collector pole piece 100 in the first direction. By limiting the length dimension D of the connecting piece 6 in the first direction to satisfy E + n×d≤D≤F / 2, it is thus coordinated with the height dimension B of the welding area 621 in the second direction, ensuring that the welding area 621 has sufficient welding area with the battery cell cover plate. On the one hand, it facilitates the welding operation between the two, and on the other hand, it ensures the welding firmness and welding quality.

[0053] In this embodiment, since the number n1 of current collectors 3 constituting the positive tab 1 is different from the number n2 of current collectors 3 constituting the negative tab 2, and the misalignment spacing dimension d1 between two adjacent current collectors 3 constituting the positive tab 1 is also different from the misalignment spacing dimension d2 between two adjacent current collectors 3 constituting the negative tab 2, the length dimension E1 of the overlapping region 5 of the positive tab 1 in the first direction is such that the length dimension D of the positive connection piece in the first direction satisfies E1 + n1×d1 ≤ D ≤ F / 2, and the length dimension D of the negative connection piece in the first direction satisfies E2 + n2×d2 ≤ D ≤ F / 2. The optimal value range of the length dimension F of the composite current collector electrode 100 in the first direction is 50 mm ≤ F ≤ 600 mm.

[0054] In addition, since the length dimension E1 of the overlapping region 5 of the positive tab 1 in the first direction is different from the length dimension E2 of the overlapping region 5 of the negative tab 2 in the first direction, the misalignment spacing dimension d2 and the misalignment spacing dimension d1 should satisfy E2 / 100 ≤ d2 ≤ d1 < E1, so as to avoid the misalignment spacing dimensions d1 and d2 being too small, resulting in too small a contact area between the current collector 3 and the connection piece 6 and reducing the conduction rate.

[0055] Optionally, as Figure 3 shown, the number n of current collectors 3 constituting a single tab satisfies 0 < n ≤ (F - E) / d. By limiting the number n of current collectors 3 constituting a single tab to satisfy 0 < n ≤ (F - E) / d, the number of current collectors 3 on the composite current collector electrode 100 is ensured to be appropriate, so that the misalignment spacing dimension d between two adjacent current collectors 3 will not be too small, thus affecting the connection area between each current collector 3 and the branch portion 61 of the connection piece 6 and resulting in a reduction in the conduction rate.

[0056] In this embodiment, the number n1 of current collectors 3 constituting the positive tab 1 satisfies 0 < n1 ≤ (F - E1) / d1, and the number n2 of current collectors 3 constituting the negative tab 2 satisfies 0 < n2 ≤ (F - E2) / d2.

[0057] Optionally, as Figure 3 shown, the length dimension E of the overlapping region 5 in the first direction satisfies F / 20 ≤ E ≤ F / 2. By limiting the length dimension E of the overlapping region 5 in the first direction to satisfy F / 20 ≤ E ≤ F / 2, on the one hand, it is avoided that the length dimension E of the overlapping region 5 is too large, resulting in a mismatch with the size of the composite current collector electrode 100, and on the other hand, it is ensured that there is a large enough contact area between the current collectors 3 to improve the stability after the current collectors 3 are in contact with each other.

[0058] In this embodiment, the length dimension E1 of the positive tab 1 overlapping area 5 in the first direction, and the length dimension of the negative tab 2 overlapping area 5 in the first direction is E2. And because the conductivity of the positive electrode material is lower than that of the negative electrode material, in order to ensure the balance of current conduction, the length dimension E1 of the positive tab 1 overlapping area 5 in the first direction is greater than the length dimension E2 of the negative tab 2 overlapping area 5 in the first direction. Therefore, the length dimension of the overlapping area 5 in the first direction should satisfy F / 20 ≤ E2 ≤ E1 ≤ F / 2.

[0059] Optionally, as Figure 3 shown, the height dimension H of the tab in the second direction satisfies 0 mm < H ≤ 100 mm. By limiting the height dimension H of the tab in the second direction to satisfy 0 mm < H ≤ 100 mm, sufficient current conduction area of the tab is ensured. In this embodiment, since the cell stack needs to satisfy the principle of negative wrapping positive when being manufactured by the stacking or winding process, the area of the negative composite current collector electrode is larger than that of the positive composite current collector electrode. In order to ensure the normal connection of the positive tab 1 of the positive composite current collector electrode, the height H1 of the positive tab 1 of the positive composite current collector electrode is greater than the height H2 of the negative tab 2 of the negative composite current collector electrode. Therefore, when setting the height dimensions of the positive tab 1 and the negative tab 2 in the second direction, it is necessary to satisfy 0 mm < H2 ≤ H1 ≤ 100 mm.

[0060] In this embodiment, a single cell is also provided. The single cell includes the above-mentioned cell stack. The single cell further includes a housing and a cell cover plate. The cell cover plate is disposed on the housing to construct a chamber for accommodating the cell stack. By applying the above-mentioned cell stack, the production cycle is shortened, the production output is increased, and the product quality is improved.

[0061] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. The electrode assembly of the battery cell, the electrode assembly of the battery cell includes multiple layers of composite current collector electrodes and a separator disposed between two adjacent composite current collector electrodes, the composite current collector electrode includes a composite current collector body and an electrode material coating coated on the composite current collector body, and is characterized in that, The electrode group of the battery cell further includes: Tab, the tab includes a plurality of current collectors, the metal layers on both sides of each composite current collector body are connected to the current collectors, and the current collectors on the multi-layer composite current collector electrodes are distributed in a staggered manner, so as to form two current collection staggered areas and an overlapping area on the tab, and the two current collection staggered areas are located on both sides of the overlapping area along the first direction; Connecting piece, the connecting piece includes a branch part and a connecting main body part, one side of the connecting main body part is connected to the branch parts corresponding to the two current collection staggered areas one by one, the two branch parts are arranged at intervals and are respectively connected to the corresponding current collection staggered areas, and the connecting main body part is used for connecting with the battery cell cover plate.

2. The electrode assembly of the battery cell according to claim 1, wherein The connecting main body part further includes a welding area and a bending area, the bending area is arranged on the side of the welding area facing the branch part, and the welding area is used for connecting with the battery cell cover plate.

3. The electrode assembly of the battery cell according to claim 2, wherein, The height dimension of the bending area along the second direction is A, and 0mm < A ≤ 10mm is satisfied.

4. The electrode assembly of the battery cell according to claim 2, wherein, The height dimension of the welding area along the second direction is B, and 1mm < B ≤ 100mm is satisfied.

5. The electrode assembly of the battery cell according to claim 1, wherein The length dimension of the branch part along the first direction is C, and n×d ≤ C ≤ D is satisfied, where n is the number of current collectors constituting a single tab, d is the staggered spacing dimension between adjacent two current collectors, and D is the length dimension of the connecting piece along the first direction.

6. The electrode group of the battery cell according to claim 5, wherein The length dimension D of the connecting piece along the first direction satisfies E + n×d ≤ D ≤ F / 2, where E is the length dimension of the overlapping area along the first direction, and F is the length dimension of the composite current collector electrode along the first direction.

7. The electrode group of the battery cell according to claim 6, wherein The number n of current collectors constituting a single tab satisfies 0 < n ≤ (F - E) / d.

8. The electrode group of the battery cell according to claim 6, wherein The length dimension E of the overlapping area along the first direction satisfies F / 20 ≤ E ≤ F / 2.

9. The electrode group of the battery cell according to claim 1, characterized in that, The height dimension H of the tab along the second direction satisfies 0mm < H ≤ 100mm.

10. The single cell is characterized in that, The single battery cell includes the electrode group of the battery cell according to any one of claims 1-9, the single battery cell further includes a housing and the battery cell cover plate, and the battery cell cover plate is covered on the housing to construct a chamber for accommodating the electrode group of the battery cell.

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