Bipolar cell structure

Abstract

The utility model provides a bipolar cell structure which comprises a single positive pole piece, a plurality of bipolar pole pieces and a single negative pole piece which are stacked, and the plurality of bipolar pole pieces are arranged between the single positive pole piece and the single negative pole piece; the single positive polarity pole piece is connected in series with the bipolar pole piece close to the single positive polarity pole piece; the adjacent bipolar pole pieces are connected in series; the single negative pole piece is connected in series with the bipolar pole piece close to the single negative pole piece; and cavities for accommodating electrolyte are arranged between the single positive polarity pole piece and the bipolar pole piece close to the single positive polarity pole piece, between the adjacent bipolar pole pieces and between the single negative polarity pole piece and the bipolar pole piece close to the single negative polarity pole piece. And the pole pieces in the battery cells are connected in series, so that the single voltage of the battery cells can be effectively improved, the voltage of a single battery cell can meet the requirements of customers, and the PACK process of the battery pack is greatly simplified.

Description

Technical Field

[0001] The utility model belongs to the technical field of batteries, and in particular relates to a bipolar battery core structure. Background Art

[0002] Lithium battery is a common rechargeable battery, which is widely used in fields such as mobile devices and electric vehicles. It has become the focus of my country's energy structure transformation. With the rapid development of lithium battery technology, large capacity, long life, high safety and low cost have become the core keywords of new energy storage. At present, the voltage of lithium battery cells generally does not exceed 5V, which is far from meeting the client's requirements for battery voltage. In the customer application end, the voltage of the battery pack is basically between a dozen volts and thousands of volts. Therefore, the battery cells need to be connected in series to increase the voltage of the battery pack. However, the pole pieces inside the traditional laminated cell structure are connected in parallel, and there is no function to increase the voltage of the single cell. Utility Model Content

[0003] The embodiment of the utility model provides a bipolar battery cell structure, aiming to solve the problems that the pole pieces inside the traditional laminated battery cell structure are connected in parallel and have no function of increasing the voltage of the single battery cell.

[0004] To achieve the above-mentioned purpose, the embodiment of the utility model provides a bipolar battery cell structure, comprising a stacked single positive pole piece, a plurality of bipolar pole pieces and a single negative pole piece, wherein the plurality of bipolar pole pieces are arranged between the single positive pole piece and the single negative pole piece;

[0005] The single positive pole piece is connected in series with the bipolar pole piece close to the single positive pole piece; the adjacent bipolar pole pieces are connected in series; the single negative pole piece is connected in series with the bipolar pole piece close to the single negative pole piece;

[0006] A cavity for accommodating electrolyte is provided between the single positive pole piece and the bipolar pole piece close to the single positive pole piece, between adjacent bipolar pole pieces, and between the single negative pole piece and the bipolar pole piece close to the single negative pole piece.

[0007] As a preferred embodiment, the current collectors of the single positive pole piece, each of the bipolar pole pieces and the single negative pole piece are all PET composite foils.

[0008] As a preferred embodiment, the PET composite foil includes an insulating foil, a first metal foil arranged on one side of the insulating foil, and a second metal foil arranged on one side of the insulating foil; the insulating foil is provided with a plurality of through holes; the second metal foil is provided with a plurality of protrusions, the protrusions are arranged in a one-to-one correspondence with the through holes, and the protrusions are penetrated into the through holes.

[0009] As a preferred embodiment, the plurality of through holes are evenly arranged; the protrusions are matched with the through holes; and the ends of the protrusions abut against the first metal foil.

[0010] As a preferred embodiment, the area of ​​the first metal foil is smaller than that of the second metal foil; the area of ​​the region where the through holes are located is smaller than or equal to that of the first metal foil. This arrangement enables the negative electrode of the second metal foil to completely cover the positive electrode of the first metal foil, and enables the first metal foil and the second metal foil to be connected through the through holes, so that the electrons on both sides of the positive and negative electrodes are conductive.

[0011] As a preferred embodiment, when the bipolar battery cell structure is a lithium-ion battery cell structure, the first metal foil is an aluminum foil, and the second metal foil is a copper foil.

[0012] As a preferred embodiment, when the bipolar battery cell structure is a sodium ion battery cell structure, the first metal foil is an aluminum foil, and the second metal foil is a copper foil or an aluminum foil.

[0013] As a preferred embodiment, when the bipolar battery cell structure is a lithium-ion battery cell structure, in the single positive polarity electrode sheet, a positive electrode coating is evenly coated on the side of the first metal foil away from the insulating foil.

[0014] As a preferred embodiment, when the bipolar battery cell structure is a lithium-ion battery cell structure, in the single negative polarity electrode sheet, the side of the second metal foil away from the insulating foil is evenly coated with a negative electrode coating.

[0015] As a preferred embodiment, when the bipolar battery cell structure is a lithium-ion battery cell structure, in the bipolar pole piece, the side of the first metal foil away from the insulating foil is uniformly coated with a positive electrode coating, and the side of the second metal foil away from the insulating foil is uniformly coated with a negative electrode coating.

[0016] As a preferred embodiment, the positive electrode coating of the single positive polarity pole piece is arranged adjacent to the negative electrode coating of the bipolar pole piece close to the single positive polarity pole piece; the negative electrode coating of the single negative polarity pole piece is arranged adjacent to the positive electrode coating of the bipolar pole piece close to the single negative polarity pole piece.

[0017] As a preferred embodiment, the insulating foil of the single positive pole piece and the insulating foil of the bipolar pole piece close to the single positive pole piece, the insulating foils of the adjacent bipolar pole pieces, and the insulating foil of the single negative pole piece and the insulating foil of the bipolar pole piece close to the single negative pole piece are all adhered to form an adhesion layer; the cavity is arranged close to the inner side of the adhesion layer. In this way, a cavity is formed between adjacent insulating foils for storing electrolyte, and it can be ensured that the electrolytes in adjacent cavities will not be connected.

[0018] As a preferred embodiment, the insulating foil is a PET foil or a PP foil. The insulating foil can be made of a material that can seal and insulate.

[0019] As a preferred embodiment, the bonding is performed by sealant bonding or heat pressing bonding.

[0020] As a preferred embodiment, a diaphragm is provided between the single positive pole piece and the bipolar pole piece close to the single positive pole piece, between adjacent bipolar pole pieces, and between the single negative pole piece and the bipolar pole piece close to the single negative pole piece.

[0021] The present application can effectively increase the single cell voltage of the battery cell by stacking and connecting the pole pieces in series. In the embodiment of the present application, the voltage of the battery cell is mainly determined by the number of pole pieces connected in series. There is no need to connect the battery cells in series. The voltage of a single battery cell can meet the customer's requirements, which can greatly simplify the PACK process of the battery pack. A battery pack with multiple battery cells in series can be directly changed into a battery pack consisting of a single battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0023] Figure 1 It is a structural schematic diagram of a bipolar battery cell structure of an embodiment of the utility model;

[0024] Figure 2 yes Figure 1 A schematic cross-sectional structure diagram of a bipolar battery cell structure;

[0025] Figure 3 yes Figure 2 Schematic diagram of the cross-sectional structure of the PET composite foil with a bipolar battery structure;

[0026] Figure 4 yes Figure 2 A schematic cross-sectional structure diagram of a single positive polarity pole piece of a bipolar battery cell structure;

[0027] Figure 5 yes Figure 2 A schematic cross-sectional structure diagram of a single negative polarity pole piece of a bipolar battery cell structure;

[0028] Figure 6 yes Figure 2 Schematic diagram of the cross-sectional structure of the bipolar pole piece of the bipolar battery cell structure. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present utility model are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present utility model, not all of them. Based on the embodiments of the present utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present utility model.

[0030] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, top, bottom...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0031] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0032] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0033] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the utility model.

[0034] Specifically, Figure 1 to Figure 2 As shown, the embodiment of the utility model provides a bipolar battery cell structure, including a stacked single positive pole piece 10, a plurality of bipolar pole pieces 20 and a single negative pole piece 30, wherein the plurality of bipolar pole pieces 20 are arranged between the single positive pole piece 10 and the single negative pole piece 30;

[0035] The single positive pole piece 10 is connected in series with the bipolar pole piece 20 close to the single positive pole piece 10; the adjacent bipolar pole pieces 20 are connected in series; the single negative pole piece 30 is connected in series with the bipolar pole piece 20 close to the single negative pole piece 30;

[0036] A cavity 40 for containing electrolyte is provided between the single positive pole piece 10 and the bipolar pole piece 20 close to the single positive pole piece 10 , between adjacent bipolar pole pieces 20 , and between the single negative pole piece 30 and the bipolar pole piece 20 close to the single negative pole piece 30 .

[0037] As a preferred embodiment, the current collectors of the single positive pole piece 10 , each of the bipolar pole pieces 20 , and the single negative pole piece 30 are all PET composite foil M.

[0038] As a preferred embodiment, Figure 3 As shown, the PET composite foil M includes an insulating foil M1, a first metal foil M2 arranged on one side of the insulating foil M1, and a second metal foil M3 arranged on one side of the insulating foil M1; the insulating foil M1 is provided with a plurality of through holes (not marked in the figure); the second metal foil M3 is provided with a plurality of protrusions M31, the protrusions M31 are arranged in a one-to-one correspondence with the through holes, and the protrusions M31 are penetrated into the through holes.

[0039] As a preferred embodiment, a plurality of the through holes are evenly arranged; the protrusions M31 are matched with the through holes; and the ends of the protrusions M31 abut against the first metal foil M2.

[0040] As a preferred embodiment, the area of ​​the first metal foil M2 is smaller than the area of ​​the second metal foil M3; the area of ​​the region where the through holes are located is smaller than or equal to the area of ​​the first metal foil M2. This arrangement enables the negative electrode of the second metal foil M3 to completely cover the positive electrode of the first metal foil M2, and enables the first metal foil M2 and the second metal foil M3 to be connected through the through holes, so that the electrons on both sides of the positive and negative electrodes are conductive.

[0041] As a preferred embodiment, when the bipolar battery cell structure is a lithium-ion battery cell structure, the first metal foil M2 is an aluminum foil, and the second metal foil M3 is a copper foil.

[0042] As a preferred embodiment, when the bipolar battery cell structure is a sodium ion battery cell structure, the first metal foil M2 is an aluminum foil, and the second metal foil M3 is a copper foil or an aluminum foil.

[0043] As a preferred embodiment, Figure 4 As shown, when the bipolar battery cell structure is a lithium-ion battery cell structure, in the single positive polarity electrode sheet 10 , the side of the first metal foil M2 away from the insulating foil M1 is uniformly coated with a positive electrode coating 11 .

[0044] As a preferred embodiment, Figure 5 As shown, when the bipolar battery cell structure is a lithium-ion battery cell structure, in the single negative pole piece 30 , the side of the second metal foil M3 away from the insulating foil M1 is uniformly coated with a negative electrode coating 31 .

[0045] As a preferred embodiment, Figure 6 As shown, when the bipolar battery cell structure is a lithium-ion battery cell structure, in the bipolar pole piece 20, the side of the first metal foil M2 away from the insulating foil M1 is uniformly coated with a positive electrode coating 21, and the side of the second metal foil M3 away from the insulating foil M1 is uniformly coated with a negative electrode coating 22.

[0046] As a preferred embodiment, the positive electrode coating 11 of the single positive polarity pole sheet 10 is arranged adjacent to the negative electrode coating 22 of the bipolar pole sheet 20 close to the single positive polarity pole sheet 10; the negative electrode coating 31 of the single negative polarity pole sheet 30 is arranged adjacent to the positive electrode coating 21 of the bipolar pole sheet 20 close to the single negative polarity pole sheet 30.

[0047] As a preferred embodiment, the insulating foil M1 of the single positive pole piece 10 and the insulating foil M1 of the bipolar pole piece 20 close to the single positive pole piece 10, the insulating foil M1 of the adjacent bipolar pole pieces 20, and the insulating foil M1 of the single negative pole piece 30 and the insulating foil M1 of the bipolar pole piece 20 close to the single negative pole piece 30 are all adhered to form an adhesion layer 50; the cavity 40 is arranged close to the inner side of the adhesion layer 50. In this way, a cavity 40 is formed between adjacent insulating foils M1 for storing electrolyte, and it can be ensured that the electrolytes in adjacent cavities 40 will not be connected.

[0048] As a preferred embodiment, the insulating foil M1 is a PET foil or a PP foil. The insulating foil can be made of any material that can seal and insulate. Specifically, in this embodiment, the insulating foil M1 is a PET foil.

[0049] As a preferred embodiment, the bonding is performed by sealant bonding or heat pressing bonding.

[0050] As a preferred embodiment, a diaphragm 60 is provided between the single positive pole piece 10 and the bipolar pole piece 20 close to the single positive pole piece 10, between adjacent bipolar pole pieces 20, and between the single negative pole piece 30 and the bipolar pole piece 20 close to the single negative pole piece 30. In this way, the dual-cell structure from positive to negative is: single positive pole piece 10-diaphragm 60-(negative 22) bipolar pole piece 20 (positive 21)-diaphragm 60-(negative 22) bipolar pole piece 20 (positive 21)-diaphragm 60-...-(negative 22) bipolar pole piece 20 (positive 21)-diaphragm 60-single negative pole piece 30.

[0051] Taking the battery cell structure containing five bipolar pole pieces as an example, if the battery cell is a lithium iron phosphate system with a voltage platform of 3.2V, the battery cell composed of a single positive pole piece, a single negative pole piece and five bipolar pole pieces can reach a voltage of 3.2*6=19.2V at both ends. If the voltage needs to be further increased, the number of stacked layers of the bipolar pole pieces can be increased.

[0052] The present application can effectively increase the single cell voltage of the battery cell by stacking and connecting the pole pieces in series. In the embodiment of the present application, the voltage of the battery cell is mainly determined by the number of pole pieces connected in series. There is no need to connect the battery cells in series. The voltage of a single battery cell can meet the customer's requirements, which can greatly simplify the PACK process of the battery pack. A battery pack with multiple battery cells in series can be directly changed into a battery pack consisting of a single battery cell.

[0053] In the description of this specification, the description with reference to the terms "an embodiment", "example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0054] In addition, it should be understood that although this specification is described according to implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A bipolar battery cell structure, characterized in that: It comprises a single positive pole piece, a plurality of bipolar pole pieces and a single negative pole piece which are stacked, wherein the plurality of bipolar pole pieces are arranged between the single positive pole piece and the single negative pole piece; The single positive pole piece is connected in series with the bipolar pole piece close to the single positive pole piece; the adjacent bipolar pole pieces are connected in series; the single negative pole piece is connected in series with the bipolar pole piece close to the single negative pole piece; A cavity for accommodating electrolyte is provided between the single positive pole piece and the bipolar pole piece close to the single positive pole piece, between adjacent bipolar pole pieces, and between the single negative pole piece and the bipolar pole piece close to the single negative pole piece.

2. The bipolar battery cell structure according to claim 1, characterized in that: The current collectors of the single positive pole piece, each of the bipolar pole pieces and the single negative pole piece are all PET composite foils.

3. The bipolar battery cell structure according to claim 2, characterized in that: The PET composite foil includes an insulating foil, a first metal foil arranged on one side of the insulating foil, and a second metal foil arranged on one side of the insulating foil; the insulating foil is provided with a plurality of through holes; the second metal foil is provided with a plurality of protrusions, the protrusions are arranged in a one-to-one correspondence with the through holes, and the protrusions are penetrated into the through holes.

4. The bipolar battery cell structure according to claim 3, characterized in that: The plurality of through holes are evenly arranged; the protrusions are matched with the through holes; and the ends of the protrusions are in contact with the first metal foil.

5. The bipolar battery cell structure according to claim 3, characterized in that: The area of ​​the first metal foil is smaller than that of the second metal foil; and the areas of the regions where the through holes are located are smaller than or equal to the area of ​​the first metal foil.

6. The bipolar battery cell structure according to claim 3, characterized in that: When the bipolar battery cell structure is a lithium-ion battery cell structure, the first metal foil is an aluminum foil, and the second metal foil is a copper foil; When the bipolar battery cell structure is a sodium ion battery cell structure, the first metal foil is an aluminum foil, and the second metal foil is a copper foil or an aluminum foil.

7. The bipolar battery cell structure according to claim 6, characterized in that: When the bipolar battery cell structure is a lithium-ion battery cell structure, in the single positive polarity electrode sheet, the side of the first metal foil away from the insulating foil is evenly coated with a positive electrode coating; When the bipolar battery cell structure is a lithium-ion battery cell structure, in the single negative polarity pole piece, the side of the second metal foil away from the insulating foil is evenly coated with a negative electrode coating; When the bipolar battery cell structure is a lithium-ion battery cell structure, in the bipolar pole piece, the side of the first metal foil away from the insulating foil is uniformly coated with a positive electrode coating, and the side of the second metal foil away from the insulating foil is uniformly coated with a negative electrode coating.

8. The bipolar battery cell structure according to claim 7, characterized in that: The positive electrode coating of the single positive polarity pole piece is arranged adjacent to the negative electrode coating of the bipolar pole piece close to the single positive polarity pole piece; the negative electrode coating of the single negative polarity pole piece is arranged adjacent to the positive electrode coating of the bipolar pole piece close to the single negative polarity pole piece.

9. The bipolar battery cell structure according to claim 8, characterized in that: The insulating foil of the single positive pole piece and the insulating foil of the bipolar pole piece close to the single positive pole piece, the insulating foils of adjacent bipolar pole pieces, and the insulating foil of the single negative pole piece and the insulating foil of the bipolar pole piece close to the single negative pole piece are all adhered to form an adhesion layer; the cavity is arranged close to the inner side of the adhesion layer.

10. The bipolar battery cell structure according to claim 9, characterized in that: The insulating foil is PET foil or PP foil; The bonding is by sealant bonding or by heat pressing bonding; A diaphragm is provided between the single positive pole piece and the bipolar pole piece close to the single positive pole piece, between adjacent bipolar pole pieces, and between the single negative pole piece and the bipolar pole piece close to the single negative pole piece.

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