Electrode assembly, battery cell, battery and electric equipment

Abstract

The utility model provides an electrode assembly, a battery monomer, a battery and electric equipment. The electrode assembly may include a pole piece, a separator, and a patch. The pole pieces comprise a positive pole piece and a negative pole piece. And the positive pole pieces and the negative pole pieces are alternately arranged in the thickness direction of the pole pieces. And a thinned area is formed at the end part of the pole piece. And the diaphragms are arranged on two opposite sides of the pole piece along the thickness direction. And the patch is arranged corresponding to the thinned area along the thickness direction. And the patch is positioned on the outer side of the outermost diaphragm along the thickness direction. The patch is attached to the diaphragm. The patch is configured as a member made of a swellable material. According to the lithium ion battery, the patches are correspondingly arranged in the thinned areas and can absorb electrolyte to be swelled and thickened after liquid injection of the battery, so that the difference between the thickness of the thinned areas and the thickness of other parts is counteracted, the positive and negative plates in the thinned areas can be tightly attached together by the patches after swelling, the transmission distance of lithium ions is further reduced, and the lithium ion battery has the advantages that the lithium ion battery is more compact in structure and more compact in structure. The transmission resistance of lithium ions is reduced and the cycle life of the battery is prolonged.

Description

Technical Field

[0001] The utility model generally relates to the technical field of batteries, and more specifically to an electrode assembly, a battery cell, a battery and an electrical device. Background Art

[0002] Related Technology In the process of producing pole pieces, due to the limitations of process coating, rolling and other processes, the edges of the dressing foil will become thinner, commonly known as the thinning area. During the battery cycle, as the battery is charged and discharged and the number of charge and discharge times increases, the pole piece will continue to expand and contract, and the thickness will continue to increase or decrease. In this way, the distance between the pole pieces will increase in the thinning area. When the electrolyte is consumed to a certain extent, the lithium ion transmission resistance between the positive and negative pole pieces increases, and the interface deteriorates, which will cause the battery capacity to plummet and affect the battery cycle life. Utility Model Content

[0003] A series of simplified concepts are introduced in the utility model content section, which will be further described in detail in the detailed implementation section. The utility model content section of the utility model does not mean to attempt to define the key features and essential technical features of the technical solution claimed for protection, nor does it mean to attempt to determine the scope of protection of the technical solution claimed for protection.

[0004] In order to at least partially solve the above problems, the first aspect of the present invention provides an electrode assembly, the electrode assembly comprising:

[0005] A pole piece, wherein the pole piece comprises a positive pole piece and a negative pole piece, the positive pole piece and the negative pole piece are alternately arranged in a thickness direction of the pole piece, and a thinning area is formed at an end of the pole piece;

[0006] A diaphragm, which is disposed on two opposite sides of the pole piece in the thickness direction; and

[0007] A patch is arranged along the thickness direction corresponding to the thinned area, and the patch is located on the outside of the outermost diaphragm along the thickness direction. The patch is attached to the diaphragm and is constructed as a component made of a swellable material.

[0008] According to the electrode assembly of the first aspect of the utility model, a patch is arranged in the corresponding thinning area, and the patch is a swellable component. When the electrode assembly is applied to a battery cell, the patch can absorb electrolyte and swell and thicken after the battery is filled with electrolyte, thereby filling the thinning area to offset the difference in thickness between the thinning area and the remaining parts. Moreover, after swelling, the patch can also exert a certain extrusion force on the thinning area, thereby making the positive and negative electrodes in the thinning area close together, thereby reducing the transmission distance of lithium ions, reducing the transmission resistance of lithium ions, and increasing the battery cycle life.

[0009] Optionally, the thinned area is formed at the pole ear end of the pole piece;

[0010] In a first direction perpendicular to the thickness direction, the tab end of the negative electrode sheet and the tab end of the positive electrode sheet are oriented in opposite directions;

[0011] The thickness of the patch increases along a direction parallel to the first direction and away from the pole piece.

[0012] Optionally, the patch is made of polyvinylidene fluoride.

[0013] Optionally, in a plane perpendicular to the thickness direction, the orthographic projection of the patch does not exceed the orthographic projection of the positive electrode sheet in a second direction perpendicular to the thickness direction.

[0014] Optionally, in a plane perpendicular to the thickness direction, a ratio of a size of an orthographic projection of the patch in the second direction to a size of an orthographic projection of the positive electrode sheet in the second direction is in a range of [0.9, 1].

[0015] Optionally, the patch includes two positive electrode patches arranged opposite to each other, the positive electrode patches are arranged corresponding to the positive electrode thinning area, and all the electrode sheets are located between the two positive electrode patches along the thickness direction.

[0016] The electrode assembly includes n positive electrode sheets, n is a positive integer and n is greater than or equal to 2, the positive electrode sheet includes a positive electrode main body area and a positive electrode thinning area, the difference between the positive electrode thinning area and the positive electrode main body area in the thickness direction is recorded as Δ1, the compression ratio of the patch is ε, and the thickness range of the positive patch is

[0017]

[0018] Optionally, the patch includes two negative electrode patches arranged opposite to each other, the negative electrode patches are arranged corresponding to the negative electrode thinning area, and all the electrode sheets are located between the two negative electrode patches along the thickness direction.

[0019] The electrode assembly includes m negative electrode sheets, m is a positive integer and m is greater than or equal to 2, the negative electrode sheet includes a negative electrode main body area and a negative electrode thinning area, the difference between the negative electrode thinning area and the negative electrode main body area in the thickness direction is Δ2, the compression ratio of the patch is ε, and the thickness of the negative electrode patch ranges from

[0020]

[0021] Optionally, the ratio of the size of the patch in the first direction to the size of the thinned area in the first direction is in the range of [0.8, 1.25]; and / or

[0022] In a plane perpendicular to the thickness direction, an orthographic projection of the patch partially extends outside an orthographic projection of the pole piece in the first direction.

[0023] A second aspect of the present invention provides a battery cell, the battery cell comprising:

[0024] a housing; and

[0025] The electrode assembly mentioned above is located inside the shell.

[0026] According to the battery cell of the second aspect of the utility model, by applying the above-mentioned electrode assembly, the swelling properties of the patch can be utilized to generate an extrusion force on the thinned area after absorbing the electrolyte, so that the positive and negative electrode sheets in the thinned area can be tightly attached together, thereby reducing the transmission distance of lithium ions, reducing the transmission resistance of lithium ions, and increasing the cycle life of the battery cell.

[0027] Optionally, the battery cell further includes:

[0028] A positive electrode column, the positive electrode column is connected to the tab end of the positive electrode sheet; and

[0029] A negative electrode column, wherein the negative electrode column is connected to the tab end of the negative electrode plate.

[0030] A third aspect of the present invention provides a battery, which includes the above-mentioned battery cell.

[0031] According to the battery of the third aspect of the present invention, by using the above-mentioned battery monomer, the cycle life of the battery can be improved.

[0032] A fourth aspect of the utility model provides an electrical device, wherein the electrical device comprises the above-mentioned battery.

[0033] According to the electrical equipment of the fourth aspect of the present invention, by applying the above-mentioned battery, the stability of the electrical equipment's power consumption can be improved and the service life can be prolonged. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The following drawings of the embodiments of the present invention are used as part of the present invention for understanding the present invention. The drawings show the embodiments of the present invention and their descriptions, and are used to explain the principles of the present invention. In the drawings,

[0035] Figure 1 is a schematic diagram of a battery cell according to a preferred embodiment of the present utility model; and

[0036] Figure 2 for Figure 1Schematic diagram of the positive electrode patch or negative electrode patch shown in .

[0037] Description of reference numerals:

[0038] 100: Battery cell 110: Positive electrode

[0039] 111: Positive electrode thinning area 112: Positive electrode main area

[0040] 113: Positive electrode tab 120: Negative electrode sheet

[0041] 121: Negative electrode thinning area 122: Negative electrode main area

[0042] 123: Negative electrode tab 130: Separator

[0043] 140: Positive electrode patch 150: Negative electrode patch

[0044] 160: Shell 170: Positive pole

[0045] 180: Negative pole D1: First direction

[0046] D2: Second direction D3: Thickness direction DETAILED DESCRIPTION

[0047] In the following description, a large number of specific details are given to provide a more thorough understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features known in the art are not described.

[0048] In order to fully understand the implementation of the present invention, a detailed structure will be presented in the following description. Obviously, the implementation of the implementation of the present invention is not limited to the specific details familiar to those skilled in the art.

[0049] It should be understood that the purpose of the terms used herein is only to describe specific embodiments and is not intended to limit the present invention, and the singular forms "a", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. When the terms "comprise" and / or "include" are used in this specification, it indicates the presence of the features, integral bodies, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integral bodies, steps, operations, elements, components and / or combinations thereof.

[0050] Ordinal numbers such as "first" and "second" cited in the present invention are merely identifiers and do not have any other meaning, such as a specific order. Moreover, for example, the term "first component" itself does not imply the existence of a "second component", and the term "second component" itself does not imply the existence of a "first component". It should be noted that the terms "upper", "lower", "front", "back", "left", "right", "inner", "outer" and similar expressions used in the present invention are for illustrative purposes only and are not limiting.

[0051] The "parallel" / "vertical" and similar expressions used in the present invention include an absolute parallel / vertical relationship and a roughly parallel / vertical relationship (for example, a relationship that differs from absolute parallel / vertical by -5° to +5°), which can have the same effect.

[0052] Hereinafter, specific embodiments of the present invention will be described in more detail with reference to the accompanying drawings. These drawings show representative embodiments of the present invention and are not intended to limit the present invention.

[0053] During the production of pole pieces, due to the limitations of process coating and rolling, the dressing will become thinner at the edge of the foil, commonly known as the thinning zone. For pole pieces with smaller widths, the thinning zone only exists at the pole ear end. For pole pieces with larger widths, the thinning zone exists not only at the pole ear end, but also at the slitting end. That is, when multiple layers of pole pieces are stacked or wound together, the thickness of the battery pole ear end or the slitting end of the battery with wider pole pieces will be smaller than the thickness of the large surface of the battery. During the battery cycle, as the battery is charged and discharged and the number of times increases, the pole piece will continue to expand and contract, and the thickness will continue to increase and decrease. In this way, the distance between the pole pieces will increase in the thinning zone. When the electrolyte is consumed to a certain extent, the transmission resistance of lithium ions between the positive and negative pole pieces will increase, and the interface will deteriorate, which will cause the battery cycle to dive.

[0054] In order to solve the above defects, the present invention provides an electrode assembly, a battery cell 100, a battery and an electrical device. Figure 1 and Figure 2 The example shown describes in detail the electrode assembly, battery cell 100, battery and electrical equipment of the present invention.

[0055] like Figure 1 and Figure 2As shown, the electrode assembly according to the utility model may include a pole piece, a diaphragm 130 and a patch. The pole piece may include a positive pole piece 110 and a negative pole piece 120. The positive pole piece 110 and the negative pole piece 120 are alternately arranged in the thickness direction D3 of the pole piece. A thinning area is formed at the end of the pole piece. The diaphragm 130 is arranged on opposite sides of the pole piece along the thickness direction D3. The patch is arranged corresponding to the thinning area along the thickness direction D3. And the patch is located on the outside of the outermost diaphragm 130 along the thickness direction D3. It can be understood here that the patch is on the outermost side of the combination of the positive pole piece 110 and the negative pole piece 120, and is located on the outer side of the outermost diaphragm 130. The patch is attached to the diaphragm 130. The patch can be constructed as a component made of a material that can swell.

[0056] According to the electrode assembly of the utility model, a patch is arranged in the corresponding thinning area, and the patch is a component that can swell. When the electrode assembly is applied to the battery cell 100, the patch can absorb electrolyte and swell and thicken after the battery is filled with electrolyte, thereby filling the thinning area to offset the difference in thickness between the thinning area and the remaining parts. Moreover, after swelling, the patch can also generate a certain extrusion force on the thinning area, so that the positive and negative electrode sheets in the thinning area can be tightly attached together, thereby reducing the transmission distance of lithium ions, reducing the transmission resistance of lithium ions, and increasing the battery cycle life.

[0057] like Figure 1 As shown, for example, the thinning area is formed at the pole ear end of the pole piece. The thinning area may include a positive pole thinning area 111 and a negative pole thinning area 121. The thinning area of ​​the positive pole piece 110 is the positive pole thinning area 111. The thinning area of ​​the negative pole piece 120 is the negative pole thinning area 121. The positive pole piece 110 includes a positive pole ear 113. The positive pole ear 113 extends from the pole ear end of the positive pole piece 110. The negative pole piece 120 includes a negative pole ear 123. The negative pole ear 123 extends from the pole ear end of the negative pole piece 120. It can be seen from the example shown in the figure that the positive pole ear 113 and the negative pole ear 123 are in opposite directions in the battery cell 100. In the first direction D1 perpendicular to the thickness direction D3, the pole ear end of the negative pole piece 120 and the pole ear end of the positive pole piece 110 are in opposite directions. The thickness of the patch increases in a direction parallel to the first direction D1 and away from the pole piece. In other words, the thickness of the patch increases in a direction parallel to the first direction D1 and toward the outside of the pole piece. This enables the patch to adaptively compensate for the thickness difference of different parts of the thinned area.

[0058] For example, the patch is made of polyvinylidene fluoride (PVDF), which has the properties of being swellable and liquid-retaining.

[0059] In other examples, the patch can be constructed of other materials that are swellable and liquid-retaining and do not react with electrolytes, lithium iron phosphate, graphite, etc., such as polyurethane (Polyurethane in English, abbreviated as PU in English).

[0060] For example, in a plane perpendicular to the thickness direction D3, the orthographic projection of the patch does not exceed the orthographic projection of the positive electrode sheet 110 in the second direction D2 perpendicular to the thickness direction D3. Usually, the size of the negative electrode sheet 120 is greater than or equal to the positive electrode sheet 110. If the orthographic projection of the patch exceeds the positive electrode sheet 110 in the second direction D2, the portion of the negative electrode sheet 120 outside the positive electrode sheet 110 in the second direction D2 will be squeezed in the swollen state, causing the edge portion of the negative electrode sheet 120 to bend, and further making the distance between the negative electrode sheet 120 and the positive electrode sheet 110 in the thinning area along the thickness direction D3 inconsistent in the second direction D2. However, the present application hopes to enable the positive electrode sheet 110 and the negative electrode sheet 120 to be close to each other in the thickness direction D3 in the thinning area. In this way, it can be ensured that each portion of the thinned area of ​​the positive electrode sheet 110 along the second direction D2 can be close to the negative electrode sheet 120, so that the thickness difference of the entire thinned area can be compensated by the patch.

[0061] Furthermore, in a plane perpendicular to the thickness direction D3, the ratio of the size of the orthographic projection of the patch in the second direction D2 to the size of the orthographic projection of the positive electrode sheet 110 in the second direction D2 is in the range of [0.9, 1].

[0062] See also Figure 1 and Figure 2 For example, the patch may include two positive electrode patches 140 arranged opposite to each other. The thinned area may include a positive electrode thinned area 111. The positive electrode patch 140 is arranged corresponding to the positive electrode thinned area 111. All the electrode sheets are located between the two positive electrode patches 140 along the thickness direction D3. The cross-sectional shape of the positive electrode patch 140 perpendicular to the second direction D2 is a wedge shape.

[0063] The electrode assembly may include n positive electrode sheets 110. n is a positive integer and n is greater than or equal to 2. The positive electrode sheet 110 includes a positive electrode main body region 112 and a positive electrode thinning region 111. The difference between the positive electrode thinning region 111 and the positive electrode main body region 112 in the thickness direction D3 is denoted as Δ1. The compression ratio of the patch is ε. Then the thickness of the positive patch 140 can range from

[0064] It is understood that the minimum thickness of the positive electrode patch 140 can be The maximum thickness of the positive electrode patch 140 can be

[0065] See also Figure 1 and Figure 2 For example, the patch may include two negative electrode patches 150 arranged opposite to each other. The thinning area includes a negative electrode thinning area 121. The negative electrode patch 150 is arranged corresponding to the negative electrode thinning area 121. All the electrode sheets are located between the two negative electrode patches 150 along the thickness direction D3. The cross-sectional shape of the positive electrode patch 140 perpendicular to the second direction D2 is a wedge shape. Here, the negative electrode thinning area 121 and the positive electrode thinning area 111 are located at opposite ends of the electrode assembly along the first direction D1.

[0066] The electrode assembly may include m negative electrode sheets 120. m is a positive integer and m is greater than or equal to 2. The negative electrode sheet 120 may include a negative electrode main body region 122 and a negative electrode thinning region 121. The difference between the negative electrode thinning region 121 and the negative electrode main body region 122 in the thickness direction D3 is recorded as Δ2. Here, Δ2 may be the same as or different from the above-mentioned Δ1. The compression ratio of the patch is ε. Then the thickness of the negative electrode patch 150 may range from

[0067] It is understood that the minimum thickness of the negative electrode patch 150 can be The maximum thickness of the negative electrode patch 150 can be Here, the compression ratio of the positive electrode patch 140 and the compression ratio of the negative electrode patch 150 may be the same or different.

[0068] exist Figure 1 In the example shown, the outermost electrode sheet of the electrode assembly along the thickness direction D3 is the negative electrode sheet 120. In a plane perpendicular to the thickness direction D3, the orthographic projection of the positive electrode sheet 110 does not exceed the orthographic projection of the negative electrode sheet 120 in the first direction D1. In a plane perpendicular to the thickness direction D3, the orthographic projection of the negative electrode sheet 120 does not exceed the orthographic projection of the diaphragm 130 in the first direction D1.

[0069] For example, the ratio of the size of the patch in the first direction D1 to the size of the thinned area in the first direction D1 is in the range of [0.8, 1.25]. That is, the size of the patch in the first direction D1 can be smaller than the size of the thinned area of ​​the pole piece in the first direction D1, and the size of the patch in the first direction D1 can also slightly exceed the size of the thinned area of ​​the pole piece in the first direction D1.

[0070] exist Figure 1 In the example shown, in a plane perpendicular to the thickness direction D3, a portion of the orthographic projection of the patch is located outside the orthographic projection of the negative electrode plate 120 in the first direction D1. This ensures that the thinned area can fully utilize the swelling properties of the patch, so that each electrode in the thinned area can be squeezed by the swollen patch and kept close.

[0071] See also Figure 1 and Figure 2The utility model further provides a battery cell. The battery cell 100 may include a housing 160 and the electrode assembly described above. The electrode assembly is located inside the housing 160 .

[0072] According to the battery cell 100 of the utility model, by applying the above-mentioned electrode assembly, the swelling property of the patch can be utilized to generate an extrusion force on the thinned area after absorbing the electrolyte, so that the positive and negative electrode sheets in the thinned area can be tightly attached together, thereby reducing the transmission distance of lithium ions, reducing the transmission resistance of lithium ions, and increasing the cycle life of the battery cell 100.

[0073] See also Figure 1 In addition, the battery cell 100 may further include a positive electrode column 170 and a negative electrode column 180. The positive electrode column 170 is connected to the tab end of the positive electrode sheet 110. The negative electrode column 180 is connected to the tab end of the negative electrode sheet 120. That is, the positive electrode column 170 and the negative electrode column 180 are disposed at opposite ends of the battery cell 100.

[0074] See also Figure 1 In the production process of the battery cell 100 of the utility model, after the positive electrode sheet 110 and the negative electrode sheet 120 are stacked or wound, the thinning area can be shaped so that the positive electrode sheet 110 and the negative electrode sheet 120 in the thinning area can be attached together. The shaping method here may include but is not limited to hot pressing, restraint, etc. Then, the swellable patch is attached to the outermost side of the thinning area along the thickness direction D3, so as to make up for the thickness deviation between the thinning area and the normal area. Specifically, after the positive electrode sheet 110 and the negative electrode sheet 120 are stacked or wound, and the shaping of the pole ear end of the pole sheet is completed and the spacer is installed, the patch can be attached to the thinning area. Then, the assembly of the battery cell 100 is completed by welding, coating, shelling and other processes. The patch here has the ability to retain liquid, and can absorb electrolyte in the battery cell 100 and store the electrolyte for use in the battery cycle process. The patch here has a swelling property, and can swell and become thicker after absorbing electrolyte. The reaction force generated by the restraint of the shell 160 produces a certain degree of compression on the thinned area, so that the positive electrode sheet 110 and the negative electrode sheet 120 can be closely attached together, thereby reducing the transmission distance of lithium ions. The patch plays a corresponding role by absorbing electrolyte after the battery cell 100 is injected.

[0075] The utility model utilizes the patch's ability to retain liquid and its swellable properties. After swelling, it applies a certain extrusion force to the battery thinning, and the absorbed electrolyte can also be used in the battery cycle process. The width, thickness and length of the patch can be specifically designed according to the thinning area morphology, thinning degree and pole piece width to achieve the goal of perfect fit with the pole piece thinning area. When the patch is applied to the battery cell 100, the width of the patch here can be understood as the size of the patch along the second direction D2, the thickness is the size along the thickness direction D3, and the length is the size of the patch along the first direction D1.

[0076] The patch of the utility model is applicable not only to batteries with narrow pole pieces and thinning only at the pole ear end, but also to batteries with wide pole pieces and thinning at the split end. It is applicable not only to laminated batteries but also to wound batteries.

[0077] The utility model further provides a battery, which may include the battery cell 100 mentioned above.

[0078] According to the battery of the present invention, by applying the above-mentioned battery cell 100, the cycle life of the battery can be improved.

[0079] The utility model also provides an electric device, which may include the battery mentioned above.

[0080] According to the electric equipment of the utility model, by applying the above-mentioned battery, the stability of the electric equipment's power consumption can be improved, and the service life of the electric equipment can be prolonged.

[0081] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art in the technical field of the present invention. The terms used herein are only for describing specific implementation purposes and are not intended to limit the present invention. Terms such as "setting" appearing in this article may indicate that one component is directly attached to another component, or that one component is attached to another component through an intermediate. Features described in this article in one embodiment may be applied to another embodiment alone or in combination with other features, unless the feature is not applicable in the other embodiment or otherwise specified.

[0082] The utility model has been described through the above embodiments, but it should be understood that the above embodiments are only for the purpose of example and description, and are not intended to limit the utility model to the described embodiments. It can be understood by those skilled in the art that more variations and modifications can be made according to the teachings of the utility model, and these variations and modifications all fall within the scope of the protection claimed by the utility model.

Claims

1. An electrode assembly, characterized in that: The electrode assembly comprises: A pole piece, wherein the pole piece comprises a positive pole piece and a negative pole piece, the positive pole piece and the negative pole piece are alternately arranged in a thickness direction of the pole piece, and a thinning area is formed at an end of the pole piece; A diaphragm, which is disposed on two opposite sides of the pole piece in the thickness direction; and A patch is arranged along the thickness direction corresponding to the thinned area, and the patch is located on the outside of the outermost diaphragm along the thickness direction. The patch is attached to the diaphragm and is constructed as a component made of a swellable material.

2. The electrode assembly according to claim 1, characterized in that: The thinned area is formed at the pole ear end of the pole piece; In a first direction perpendicular to the thickness direction, the tab end of the negative electrode sheet and the tab end of the positive electrode sheet are oriented in opposite directions; The thickness of the patch increases along a direction parallel to the first direction and away from the pole piece.

3. The electrode assembly according to claim 1, characterized in that: The patch is a component made of polyvinylidene fluoride.

4. The electrode assembly according to claim 1, characterized in that: In a plane perpendicular to the thickness direction, the orthographic projection of the patch does not exceed the orthographic projection of the positive electrode sheet in a second direction perpendicular to the thickness direction.

5. The electrode assembly according to claim 4, characterized in that: In a plane perpendicular to the thickness direction, the ratio of the size of the orthographic projection of the patch in the second direction to the size of the orthographic projection of the positive electrode sheet in the second direction is in the range of [0.9, 1].

6. The electrode assembly according to claim 1, characterized in that: The patch includes two positive electrode patches arranged opposite to each other, and all the electrode patches are located between the two positive electrode patches along the thickness direction. The electrode assembly includes n positive electrode sheets, n is a positive integer and n is greater than or equal to 2, the positive electrode sheet includes a positive main body area and a positive thinning area, the positive thinning area is arranged corresponding to the positive patch, the difference between the positive thinning area and the positive main body area in the thickness direction is recorded as Δ1, the compression ratio of the patch is ε, and the thickness range of the positive patch is 7. The electrode assembly according to claim 1, characterized in that: The patch includes two negative electrode patches arranged opposite to each other, and all the electrode patches are located between the two negative electrode patches along the thickness direction. The electrode assembly includes m negative electrode sheets, m is a positive integer and m is greater than or equal to 2, the negative electrode sheet includes a negative electrode main area and a negative electrode thinning area, the negative electrode thinning area is arranged corresponding to the negative electrode patch, the difference between the negative electrode thinning area and the negative electrode main area in the thickness direction is recorded as Δ2, the compression ratio of the patch is ε, and the thickness of the negative electrode patch ranges from 8. The electrode assembly according to claim 2, characterized in that: The ratio of the size of the patch in the first direction to the size of the thinned area in the first direction is in the range of [0.8, 1.25]; and / or In a plane perpendicular to the thickness direction, an orthographic projection of the patch partially extends outside an orthographic projection of the pole piece in the first direction.

9. A battery cell, characterized in that: The battery cell comprises: a housing; and The electrode assembly according to any one of claims 1 to 8, wherein the electrode assembly is located inside the shell.

10. The battery cell according to claim 9, characterized in that: The battery cell further comprises: A positive electrode column, the positive electrode column is connected to the tab end of the positive electrode sheet; and A negative electrode column, wherein the negative electrode column is connected to the tab end of the negative electrode plate.

11. A battery, characterized in that: The battery comprises the battery cell according to claim 9 or 10.

12. An electrical device, characterized in that: The electric device comprises the battery according to claim 11.

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