Bipolar cell structure

Abstract

The utility model provides a bipolar battery cell structure which comprises a first end plate, a battery cell body and a second end plate which are stacked, and the battery cell body is arranged between the first end plate and the second end plate; the battery cell body comprises a first unipolar pole piece, a plurality of bipolar pole pieces and a second unipolar pole piece which are stacked, and the plurality of bipolar pole pieces are arranged between the first unipolar pole piece and the second unipolar pole piece; the first unipolar pole piece is arranged close to the first end plate, and the second unipolar pole piece is arranged close to the second end plate; sealing units are formed between the first unipolar pole piece and the bipolar pole piece close to the first unipolar pole piece, between the adjacent bipolar pole pieces and between the second unipolar pole piece and the bipolar pole piece close to the second unipolar pole piece. According to the invention, the problem of unit sealing of the bipolar battery cell can be solved, and the voltage of a single battery cell can meet the requirements of customers.

Description

Technical Field

[0001] The utility model belongs to the technical field of batteries, and particularly relates to a bipolar cell structure. Background Art

[0002] With the rise and development of new energy, the application scenarios of lithium batteries are also increasing. Lithium batteries are a common type of rechargeable battery and have currently become a key point in the transformation of China's energy structure. With the rapid development of lithium battery technology, lithium batteries are widely used in fields such as mobile devices and electric vehicles. However, due to the relatively low voltage of a single cell, regardless of the application scenario in which the lithium battery is used, it is necessary to be connected in series to form a battery pack for application. In the traditional cell structure, the polarities on both sides of the electrode plate are the same, and each electrode plate is connected in parallel through a stacking method to increase the capacity of the cell, but the voltage of the cell cannot be increased, making it difficult to meet the actual usage requirements. Summary of the Utility Model

[0003] An embodiment of the utility model provides a bipolar cell structure, aiming to solve problems such as the same polarities on both sides of the electrode plate of the existing lithium battery, difficulty in increasing the voltage of the cell by stacking, and inability to meet the actual usage requirements.

[0004] To achieve the above object, an embodiment of the utility model provides a bipolar cell structure, including a first end plate, a cell body, and a second end plate stacked. The cell body is disposed between the first end plate and the second end plate;

[0005] The cell body includes a first unipolar electrode plate, a plurality of bipolar electrode plates, and a second unipolar electrode plate stacked. The plurality of bipolar electrode plates are disposed between the first unipolar electrode plate and the second unipolar electrode plate; the first unipolar electrode plate is disposed close to the first end plate, and the second unipolar electrode plate is disposed close to the second end plate;

[0006] Sealing units are formed between the first unipolar electrode plate and the bipolar electrode plate close to the first unipolar electrode plate, between adjacent bipolar electrode plates, and between the second unipolar electrode plate and the bipolar electrode plate close to the second unipolar electrode plate.

[0007] As a preferred embodiment, insulating ring diaphragms are provided between the first unipolar electrode plate and the bipolar electrode plate close to the first unipolar electrode plate, between adjacent bipolar electrode plates, and between the second unipolar electrode plate and the bipolar electrode plate close to the second unipolar electrode plate.

[0008] As a preferred embodiment, the insulating ring diaphragm includes a diaphragm and an insulating ring, and the insulating ring is circumferentially arranged on the edge of one side of the diaphragm. The positive and negative electrodes are separated by the diaphragm, and the diaphragm is fixed by the insulating ring, which can effectively prevent the diaphragm from shifting and causing a short circuit.

[0009] As a preferred embodiment, the first unipolar electrode is a single positive electrode, and the second unipolar electrode is a single negative electrode; or,

[0010] The first unipolar electrode is a single negative electrode, and the second unipolar electrode is a single positive electrode.

[0011] As a preferred embodiment, the current collectors of the single positive electrode, each bipolar electrode, and the single negative electrode are all metal current collectors.

[0012] As a preferred embodiment, on one side of the metal current collector in the single positive electrode, a first positive electrode coating is uniformly coated;

[0013] In the single negative electrode, a first negative electrode coating is uniformly coated on one side of the metal current collector;

[0014] In the bipolar electrode, a second positive electrode coating is uniformly coated on one side of the metal current collector, and a second negative electrode coating is uniformly coated on the other side.

[0015] As a preferred embodiment, the area of the first negative electrode coating is larger than the area of the first positive electrode coating; the first positive electrode coating and the second positive electrode coating have the same structure and size, and the first negative electrode coating and the second negative electrode coating have the same structure and size.

[0016] As a preferred embodiment, the area of the first negative electrode coating is equal to the area of the diaphragm; the sum of the area of the first positive electrode coating and the area of the insulating ring is equal to the area of the first negative electrode coating.

[0017] As a preferred embodiment, the insulating ring is arranged on the side of the diaphragm close to the first positive electrode coating / the second positive electrode coating, and a cavity is arranged between the insulating ring and the metal current collector close to the insulating ring; the sum of the depth of the cavity and the thickness of the insulating ring is equal to the thickness of the first positive electrode coating / the second positive electrode coating.

[0018] As a preferred embodiment, a sealing ring is provided between adjacent metal current collectors, each sealing ring abuts against the adjacent metal current collector, and the sealing ring is circumferentially arranged outside the first negative electrode coating / the second negative electrode coating; the insulating ring abuts against the sealing ring, the separator, and the first positive electrode coating / the second positive electrode coating adjacent to the insulating ring respectively.

[0019] As a preferred embodiment, the sum of the areas of the sealing ring and the first negative electrode coating / the second negative electrode coating is equal to the area of the metal current collector; the area of the metal current collector is equal to the area of the first end plate / second end plate.

[0020] As a preferred embodiment, first through holes are circumferentially provided on the first end plate, the second end plate, and the metal current collector; second through holes are circumferentially provided on the sealing ring; the first through holes and the second through holes are arranged in one-to-one correspondence, and the aperture of the first through hole is greater than or equal to the aperture of the second through hole.

[0021] As a preferred embodiment, the bipolar battery cell structure further includes a plurality of bolts, and the bolts are arranged in one-to-one correspondence with the first through holes (or second through holes); the bolts pass through the first through holes and the second through holes to clamp and fix the bipolar battery cell structure.

[0022] Each sealing ring is pressed tightly by bolts and the two end plates, so as to ensure that the electrolyte in each sealing unit will not leak or flow between units (flow between units means that the electrolytes of two or more sealing units can flow into each other. Since the withstand voltage of the electrolyte is less than 5V, the maximum voltage of each sealing unit can reach more than 3.65V. If the electrolytes of two or more sealing units are electrically connected to each other, it will exceed the withstand voltage of the electrolyte, resulting in the decomposition of the electrolyte).

[0023] As a preferred embodiment, an insulating sleeve is sleeved on the side surface of each bolt, and the sleeve abuts against the first through hole and the second through hole respectively. Through the insulating sleeve, short circuits between each sealing unit can be prevented.

[0024] With such an arrangement, the sealing ring will not shift during clamping. The aperture of the first through hole is greater than or equal to the aperture of the second through hole, which can prevent the metal current collector from piercing the sleeve of the bolt and causing a short circuit.

[0025] As a preferred embodiment, threaded holes for connecting test equipment / battery cells are provided on both the first end plate and the second end plate. The test equipment or the battery cell can also be laser welded to the first end plate (second end plate), so that the threaded holes do not need to be provided.

[0026] As a preferred embodiment, the first unipolar pole piece is connected in series with the bipolar pole piece adjacent to the first unipolar pole piece; adjacent bipolar pole pieces are connected in series; the second unipolar pole piece is connected in series with the bipolar pole piece adjacent to the second unipolar pole piece.

[0027] As a preferred embodiment, the bipolar battery cell structure is a square structure or a circular structure.

[0028] Compared with the prior art, the present application has the following technical effects and advantages:

[0029] In the present application, the sealing unit is sealed by the two end plates, the sealing ring, the insulating diaphragm and the bolts, effectively solving the problem of unit sealing of the bipolar battery cell, thereby ensuring that the electrolyte in each sealing unit will not leak or flow through. By laminating and connecting the pole pieces inside the battery cell in series, the present application can effectively increase the single-cell voltage of the battery cell. In the embodiments of the present application, the voltage of the battery cell is mainly determined by the number of stacked battery cell layers. There is no need to connect the battery cells in series, and the voltage of a single battery cell can meet the requirements of customers, which can greatly simplify the PACK process of the battery pack. A battery pack with multiple battery cells connected in series can be directly changed into a battery pack composed of a single battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0031] Figure 1 is the overall structural schematic diagram of the bipolar battery cell structure according to an embodiment of the present invention;

[0032] Figure 2 is Figure 1 the cross-sectional structural schematic diagram of the bipolar battery cell structure;

[0033] Figure 3 is Figure 1 the structural schematic diagram of the first end plate;

[0034] Figure 4 is Figure 1 the structural schematic diagram of the metal current collector;

[0035] Figure 5 is Figure 1 the structural schematic diagram of the sealing ring;

[0036] Figure 6 is Figure 1Schematic diagram of the structure of the insulating ring diaphragm;

[0037] Figure 7 is Figure 6 Enlarged schematic diagram at M;

[0038] Figure 8 Schematic diagram of the structure of the bipolar battery cell according to another embodiment of the present application. Detailed implementation manners

[0039] The technical solutions in the embodiments of the present utility model will be clearly and completely described below. Apparently, the described embodiments are only a part of the embodiments of the present utility model, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0040] It should be noted that if there are directional indications (such as up, down, left, right, front, back, top, bottom...) involved in the embodiments of the present utility model, the directional indications are only used to explain the relative position relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0041] In the present application, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0042] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time.

[0043] In addition, if the descriptions such as "first" and "second" are involved in the embodiments of the present utility model, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present utility model.

[0044] Specifically, as Figures 1 to 7 shown, an embodiment of the present utility model provides a bipolar cell structure, including a first end plate 10, a cell body 20, and a second end plate 30 which are stacked. The cell body 20 is disposed between the first end plate 10 and the second end plate 30.

[0045] The cell body 20 includes a first unipolar pole piece 21, a plurality of bipolar pole pieces 22, and a second unipolar pole piece 23 which are stacked. The plurality of bipolar pole pieces 22 are disposed between the first unipolar pole piece 21 and the second unipolar pole piece 23. The first unipolar pole piece 21 is disposed close to the first end plate 10, and the second unipolar pole piece 23 is disposed close to the second end plate 30.

[0046] Sealing units (not marked in the figure) are formed between the first unipolar pole piece 21 and the bipolar pole piece 22 close to the first unipolar pole piece 21, between adjacent bipolar pole pieces 22, and between the second unipolar pole piece 23 and the bipolar pole piece 22 close to the second unipolar pole piece 23.

[0047] As a preferred embodiment, insulating ring diaphragms 40 are disposed between the first unipolar pole piece 21 and the bipolar pole piece 22 close to the first unipolar pole piece 21, between adjacent bipolar pole pieces 22, and between the second unipolar pole piece 23 and the bipolar pole piece 22 close to the second unipolar pole piece 23.

[0048] As a preferred embodiment, the insulating ring diaphragm 40 includes a diaphragm 41 and an insulating ring 42. The insulating ring 42 is circumferentially disposed on the edge of one side of the diaphragm 41. The positive and negative electrodes are separated by the diaphragm 41, and the diaphragm 41 is fixed by the insulating ring 42, which can effectively prevent the diaphragm 41 from shifting and causing a short circuit.

[0049] As a preferred embodiment, the first unipolar pole piece 21 is a single positive polarity pole piece, and the second unipolar pole piece 23 is a single negative polarity pole piece; or,

[0050] The first unipolar electrode 21 is a single negative electrode, and the second unipolar electrode 23 is a single positive electrode.

[0051] Specifically, in this embodiment, the first unipolar electrode 21 is a single negative electrode, and the second unipolar electrode 23 is a single positive electrode.

[0052] As a preferred embodiment, the current collectors of the single positive electrode, each bipolar electrode 22, and the single negative electrode are all metal current collectors. In the embodiments of the present application, each metal current collector has the same structure and size, which can ensure the stability of the cell performance.

[0053] As a preferred embodiment, in this embodiment, on one side of the metal current collector 231 of the second unipolar electrode 23, a first positive electrode coating 232 is uniformly coated;

[0054] On one side of the metal current collector 211 of the first unipolar electrode 21, a first negative electrode coating 212 is uniformly coated;

[0055] In each bipolar electrode 22, on one side of the metal current collector 221, a second positive electrode coating 222 is uniformly coated, and on the other side, a second negative electrode coating 223 is uniformly coated;

[0056] The area of the first negative electrode coating 212 / second negative electrode coating 223 is larger than the area of the first positive electrode coating 232 / second positive electrode coating 222.

[0057] In the embodiments of the present application, the first negative electrode coating 212 and the second negative electrode coating 223 have the same structure and size, and the first positive electrode coating 232 and the second positive electrode coating 222 have the same structure and size.

[0058] As a preferred embodiment, the area of the first negative electrode coating 212 / second negative electrode coating 223 is equal to the area of the separator 41; the sum of the area of the first positive electrode coating 232 / second positive electrode coating 222 and the area of the insulating ring 42 is equal to the area of the first negative electrode coating 212 / second negative electrode coating 223.

[0059] As a preferred embodiment, the insulating ring 42 is disposed on the side of the separator 41 close to the first positive electrode coating 232 / second positive electrode coating 222, and a cavity 50 is provided between the insulating ring 42 and the metal current collector 231 / 221 close to the insulating ring 42. Through the cavity 50, the electrolyte of each sealing unit can be accommodated.

[0060] As a preferred embodiment, the sum of the depth of the cavity 50 and the thickness of the insulating ring 42 is equal to the thickness of the first positive electrode coating 232 / second positive electrode coating 222.

[0061] As a preferred embodiment, a sealing ring 60 is provided between adjacent metal current collectors 231 / 221 / 211. Each sealing ring 60 abuts against the adjacent metal current collector. The sealing ring 60 is circumferentially arranged outside the first negative electrode coating 212 / second negative electrode coating 223; the insulating ring 42 abuts against the sealing ring 60, the separator 41, and the positive electrode coating adjacent to the insulating ring 42 respectively.

[0062] As a preferred embodiment, the sum of the area of the sealing ring 60 and the area of the first negative electrode coating 212 / second negative electrode coating 223 adjacent to the sealing ring 60 is equal to the area of the metal current collector; the area of the metal current collector is equal to the area of the first end plate / second end plate.

[0063] As a preferred embodiment, first through holes 70 are circumferentially arranged on the first end plate 10, the second end plate 20, and the metal current collector; second through holes 61 are circumferentially arranged on the sealing ring 60; the first through holes 70 and the second through holes 61 are arranged in one-to-one correspondence, and the aperture of the first through hole 70 is greater than or equal to the aperture of the second through hole 61.

[0064] As a preferred embodiment, the bipolar battery cell structure further includes a plurality of bolts 80, and the bolts 80 are arranged in one-to-one correspondence with the first through holes 70 (or second through holes 61); the bolts 80 pass through the first through holes 70 and the second through holes 61 to clamp and fix the bipolar battery cell structure.

[0065] Each sealing ring is pressed tightly by the bolts 80 and the two end plates, thereby ensuring that the electrolyte in each sealing unit will not leak or flow through (flow through means that the electrolytes of two or more sealing units can flow into each other. Since the withstand voltage of the electrolyte is less than 5V, the maximum voltage of each sealing unit can reach more than 3.65V. If the electrolytes of two or more sealing units conduct electricity to each other, it will exceed the withstand voltage of the electrolyte and cause the electrolyte to decompose).

[0066] As a preferred embodiment, an insulating sleeve 81 is sleeved on the side of each bolt 80, and the sleeve 81 abuts against the first through hole 70 and the second through hole 61 respectively. Through the insulating sleeve 81, short circuits between each sealing unit can be prevented.

[0067] With such an arrangement, the sealing ring will not shift during clamping. The aperture of the first through hole is greater than or equal to the aperture of the second through hole, which can prevent the metal current collector from piercing the sleeve of the bolt and causing a short circuit.

[0068] As a preferred embodiment, threaded holes 90 for connecting test equipment / cells are provided on both the first end plate 10 and the second end plate 20. The test equipment or the cell can also be laser welded to the first end plate (second end plate), so that there is no need to provide threaded holes.

[0069] As a preferred embodiment, the first unipolar electrode 21 is connected in series with the bipolar electrode 22 adjacent to the first unipolar electrode 21; adjacent bipolar electrodes 22 are connected in series; the second unipolar electrode 23 is connected in series with the bipolar electrode 22 adjacent to the second unipolar electrode 23.

[0070] As a preferred embodiment, as Figure 1 shown, in this embodiment, the bipolar cell structure is a square structure. It can be understood that in other embodiments, as Figure 8 shown, the bipolar cell structure is a circular structure.

[0071] In this application, the sealing unit is sealed by two end plates, a sealing ring, an insulating ring diaphragm and bolts, effectively solving the problem of unit sealing of bipolar cells, thereby ensuring that the electrolyte in each sealing unit will not leak or cross-leak. By stacking and connecting the electrodes inside the cell in series, the single-cell voltage of the cell can be effectively increased. In the embodiment of this application, the voltage of the cell is mainly determined by the number of stacked cell layers. There is no need to connect the cells in series, and the voltage of a single cell can meet the requirements of customers, which can greatly simplify the PACK process of the battery pack. A battery pack with multiple cells connected in series can be directly changed into a battery pack composed of a single cell.

[0072] In the description of this specification, the description with reference to terms such as "one embodiment", "example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example.

[0073] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0074] The above are only the preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A bipolar battery cell structure, characterized in that: It comprises a first end plate, a battery cell body and a second end plate which are stacked, wherein the battery cell body is arranged between the first end plate and the second end plate; The battery cell body comprises a first unipolar pole piece, a plurality of bipolar pole pieces and a second unipolar pole piece which are stacked, wherein the plurality of bipolar pole pieces are arranged between the first unipolar pole piece and the second unipolar pole piece; the first unipolar pole piece is arranged close to the first end plate, and the second unipolar pole piece is arranged close to the second end plate; A sealing unit is formed between the first unipolar pole piece and the bipolar pole piece close to the first unipolar pole piece, between adjacent bipolar pole pieces, and between the second unipolar pole piece and the bipolar pole piece close to the second unipolar pole piece.

2. The bipolar battery cell structure according to claim 1, characterized in that: An insulating ring diaphragm is provided between the first unipolar pole piece and the bipolar pole piece close to the first unipolar pole piece, between adjacent bipolar pole pieces, and between the second unipolar pole piece and the bipolar pole piece close to the second unipolar pole piece.

3. The bipolar battery cell structure according to claim 2, characterized in that: The insulating ring diaphragm comprises a diaphragm and an insulating ring, and the insulating ring is circumferentially arranged on the edge of one side of the diaphragm.

4. The bipolar battery cell structure according to claim 3, characterized in that: The first unipolar pole piece is a single positive pole piece, and the second unipolar pole piece is a single negative pole piece; or, The first unipolar pole piece is a single negative pole piece, and the second unipolar pole piece is a single positive pole piece; The current collectors of the single positive pole piece, each of the bipolar pole pieces and the single negative pole piece are all metal current collectors.

5. The bipolar battery cell structure according to claim 4, characterized in that: In the single positive polarity electrode sheet, a first positive electrode coating is uniformly coated on one side of the metal current collector; In the single negative pole piece, a first negative electrode coating is uniformly coated on one side of the metal current collector; In the bipolar pole piece, one side of the metal current collector is uniformly coated with a second positive electrode coating, and the other side is uniformly coated with a second negative electrode coating; The area of ​​the first negative electrode coating is greater than that of the first positive electrode coating; the first positive electrode coating and the second positive electrode coating have the same structure and size, and the first negative electrode coating and the second negative electrode coating have the same structure and size.

6. The bipolar battery cell structure according to claim 5, characterized in that: The area of ​​the first negative electrode coating is equal to the area of ​​the separator; the sum of the area of ​​the first positive electrode coating and the area of ​​the insulating ring is equal to the area of ​​the first negative electrode coating; The insulating ring is arranged on the side of the diaphragm close to the first positive electrode coating / the second positive electrode coating, and a cavity is arranged between the insulating ring and the metal current collector close to the insulating ring; the sum of the depth of the cavity and the thickness of the insulating ring is equal to the thickness of the first positive electrode coating / the second positive electrode coating.

7. The bipolar battery cell structure according to claim 6, characterized in that: A sealing ring is provided between adjacent metal current collectors, each of the sealing rings abuts against the adjacent metal current collector, and the sealing ring is circumferentially arranged on the outside of the first negative electrode coating / the second negative electrode coating; the insulating ring abuts against the sealing ring, the diaphragm, the first positive electrode coating / the second positive electrode coating close to the insulating ring, respectively; The sum of the area of ​​the sealing ring and the area of ​​the first negative electrode coating / the second negative electrode coating is equal to the area of ​​the metal current collector; the area of ​​the metal current collector is equal to the area of ​​the first end plate / the second end plate.

8. The bipolar battery cell structure according to claim 7, characterized in that: The first end plate, the second end plate and the metal current collector are all circumferentially provided with first through holes; the sealing ring is circumferentially provided with second through holes; the first through holes and the second through holes are provided in a one-to-one correspondence, and the aperture of the first through hole is greater than or equal to the aperture of the second through hole.

9. The bipolar battery cell structure according to claim 8, characterized in that: The bipolar battery cell structure further includes a plurality of bolts, and the bolts are arranged in one-to-one correspondence with the first through holes; the bolts pass through the first through holes and the second through holes to clamp and fix the bipolar battery cell structure; An insulating sleeve is sleeved on the side surface of each bolt, and the sleeve is respectively abutted against the first through hole and the second through hole.

10. The bipolar battery cell structure according to claim 9, characterized in that: The first end plate and the second end plate are both provided with threaded holes for connecting the test equipment / battery cell; The first unipolar pole piece is connected in series with the bipolar pole piece close to the first unipolar pole piece; the adjacent bipolar pole pieces are connected in series; the second unipolar pole piece is connected in series with the bipolar pole piece close to the second unipolar pole piece; The bipolar battery cell structure is a square structure or a circular structure.

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