A lithium-ion battery

Abstract

This application relates to the field of lithium-ion batteries and discloses a lithium-ion battery including a casing, a cell assembly, a positive electrode post, and a negative electrode post. The casing includes a first casing structure and a second casing structure. The cell assembly includes a first cell and a second cell, the length of the first cell along a first direction being less than that of the second cell. The first cell includes a first surface and a second surface. The casing has a stepped surface corresponding to the second surface of the first cell. The positive tabs of both cells are electrically connected to the positive electrode post, and the negative tabs are electrically connected to the negative electrode post. The first cell includes a single-sided negative electrode sheet near the casing. The single-sided negative electrode sheet includes a first surface near the casing and a first hot melt adhesive layer located between the first surface and the casing. A first adhesive layer is formed on the edge of the single-sided negative electrode sheet corresponding to the first surface. The first adhesive layer includes a portion located between the first cell and the casing, and the thickness of the first adhesive layer is less than that of the first hot melt adhesive layer. This can improve the battery capacity and the stability of the first cell within the casing.

Description

Technical Field

[0001] This application relates to the field of lithium-ion batteries, and in particular to a lithium-ion battery. Background Technology

[0002] Lithium-ion batteries are rechargeable batteries widely used in consumer electronics and transportation, such as mobile phones, tablets, laptops, electric bicycles, and electric vehicles. A lithium-ion battery consists of a casing and the battery cells located inside the casing. The casing is irregularly shaped, while the cells are typically regular in shape. This results in low utilization of the internal space of the casing, leading to a relatively low battery capacity, which cannot meet users' increasing demand for higher battery energy density.

[0003] Therefore, how to solve the above-mentioned technical problems should be a key focus for those skilled in the art. Utility Model Content

[0004] The purpose of this application is to provide a lithium-ion battery that increases battery capacity while improving the stability of the cell assembly within the casing.

[0005] To address the aforementioned technical problems, this application provides a lithium-ion battery, comprising a casing, a cell assembly, and a positive electrode post located on the outer surface of the casing; wherein, the casing includes a first casing structure and a second casing structure, the cell assembly includes a first cell and a second cell, the length of the first cell along a first direction is less than the length of the second cell along the first direction; the first cell includes a first surface and a second surface disposed along the first direction; the first surface and the corresponding side surface of the second cell are flush.

[0006] The first housing structure and the second housing structure are connected to form a receiving cavity, and the housing has a stepped surface corresponding to the second surface of the first battery cell;

[0007] The positive tabs of the first battery cell and the second battery cell are both electrically connected to the positive terminal, and the negative tabs of the first battery cell and the second battery cell are both electrically connected to the negative terminal.

[0008] The first cell includes a single-sided negative electrode sheet near the housing. The single-sided negative electrode sheet includes a first side near the housing and a second side opposite to the first side. The battery also includes a first hot melt adhesive layer located between the first side and the housing. The edge of the single-sided negative electrode sheet corresponding to the first side is formed with a first adhesive layer. The first adhesive layer includes a portion located between the first cell and the housing. The thickness of the first adhesive layer is less than the thickness of the first hot melt adhesive layer.

[0009] Optionally, the first adhesive layer extends from the first side of the single-sided negative electrode sheet to the second cell, and / or the first cell includes a positive electrode sheet, a separator, and a negative electrode sheet, the separator including a first portion extending out of the negative electrode sheet along a first direction, and the projection of the first adhesive layer in a second direction overlaps with the projection of the first portion.

[0010] Optionally, the second cell includes a first electrode near the first cell, the first adhesive layer extends from the first side of the single-sided negative electrode to the first electrode, and / or the first electrode and the housing are bonded and fixed by a second hot melt adhesive layer, and / or a gap is left between the second hot melt adhesive layer and the first adhesive layer.

[0011] Optionally, the first shell structure is stepped, and the second shell structure is planar; or, both the first shell structure and the second shell structure are stepped.

[0012] Optionally, the battery includes a positive terminal and a negative terminal, which are located on the same side of the housing; or, the positive terminal and the negative terminal are located on two opposite sides of the housing.

[0013] And / or, the positive terminal and the negative terminal are both located in the first housing structure or both are located in the second housing structure.

[0014] Optionally, the first housing structure is stepped, and the second housing structure is planar; the first housing structure includes opposing first and second side surfaces; the first side surface is opposite to the target side surface of the battery cell assembly, the target side surface being a surface flush with the first and second battery cells, and both the positive and negative terminals are located on the first or second side surface, or one of the positive and negative terminals is located on the first side surface and the other on the second side surface; or...

[0015] Both the first housing structure and the second housing structure are stepped. The second housing structure includes a third side and a fourth side facing each other. The third side is opposite to the target side of the battery cell assembly. The positive terminal and the negative terminal are both located on the third side or the fourth side, or one of the positive terminal and the negative terminal is located on the third side and the other is located on the fourth side.

[0016] Optionally, the first side surface is a surface extending along the second direction, the second side surface is stepped, the positive terminal and the negative terminal are both located on the first side surface, and the second direction is perpendicular to the first direction; or,

[0017] Both the first and second sides are stepped. The first side includes at least a first and a second partition extending along a second direction, and a third partition extending along a first direction. The first and second partitions are staggered along the first direction. The third partition connects the first and second partitions. The positive and negative terminals are both located in the third partition. Alternatively,

[0018] The first side is a surface extending along a second direction, and the second side is stepped. The second side includes at least a fourth and a fifth section extending along the second direction, and a sixth section extending along a first direction. The fourth and fifth sections are staggered along the first direction, and the sixth section connects the fourth and fifth sections. The positive and negative terminals are both located in the fourth section or both in the sixth section; or, one of the positive and negative terminals is located on the first side, and the other is located in the fourth section.

[0019] Both the third and fourth side surfaces are surfaces extending along the second direction, and the positive and negative terminals are either both located on the third side surface or both located on the fourth side surface; or...

[0020] The third side includes at least a seventh and an eighth section extending along a second direction, and a ninth section extending along a first direction. The seventh and eighth sections are offset along the first direction, and the ninth section connects the seventh and eighth sections. Both the positive and negative terminals are located in the ninth section; or...

[0021] The third side and the fourth side are both surfaces extending along the second direction. The second side of the first housing structure includes at least a tenth section extending along the first direction and an eleventh section extending along the second direction. The positive terminal and the negative terminal are both located in the tenth section.

[0022] or,

[0023] The first side includes a first and a second partition extending along a second direction, and a third partition extending along a first direction. The first and second partitions are offset along the first direction, and the third partition connects the first and second partitions. The second side includes a fourth, a fifth, and a twelfth partition extending along a second direction, and a sixth and a thirteenth partition extending along a first direction. The fourth, fifth, and twelfth partitions are offset along the first direction, and the thirteenth partition connects the fifth and twelfth partitions. One of the positive and negative terminals is located in the second partition, and the other is located in the sixth partition; or...

[0024] Both the third and fourth sides are surfaces extending along the second direction, with one of the positive and negative terminals located on the third side and the other on the fourth side; or...

[0025] The third side includes at least a seventh and an eighth section extending along a second direction, and a ninth section extending along a first direction. The seventh and eighth sections are offset along the first direction, and the ninth section connects the seventh and eighth sections. The fourth side includes at least a fourteenth and a fifteenth section extending along a second direction, and a sixteenth section extending along a first direction. The fourteenth and fifteenth sections are offset along the first direction, and the sixteenth section connects the fourteenth and fifteenth sections. One of the positive and negative terminals is located in the ninth section, and the other is located in the sixteenth section.

[0026] Optionally, the positive and negative tabs of the first and second battery cells are both located in a target area on the same target side of the battery cell assembly. The target side is the side flush with the first and second battery cells, and the target area is the region where the projections of the first and second battery cells overlap on a horizontal plane; or,

[0027] The positive and negative tabs of both the first and second battery cells are located on any side of the battery cell assembly other than the target side; or,

[0028] One of the positive and negative tabs of the first and second battery cells is located in the target area on the target side, and the other tab is located on any side other than the target side.

[0029] Optionally, the first battery cell and the second battery cell include laminated battery cells, the positive electrode includes a first electrode and a second electrode that are electrically connected, the first electrode and the positive current collector in the laminated battery cell are integrally structured, and the second electrode is electrically connected to the positive terminal.

[0030] The negative electrode tab includes a third electrode tab and a fourth electrode tab that are electrically connected. The third electrode tab and the negative electrode current collector in the laminated battery cell are integrated into one structure. The fourth electrode tab is electrically connected to the negative electrode post.

[0031] An insulating protective layer is located on the outer surface of the first tab of all the collections; and / or, on the outer surface of the third tab of all the collections.

[0032] Optionally, the first battery cell and the second battery cell have an active material layer distributed at least in the stacked contact area; or, the first battery cell and the second battery cell have an adhesive layer distributed in the stacked contact area.

[0033] This application provides a lithium-ion battery, including a casing, a cell assembly, and a positive electrode post and a negative electrode post located on the outer surface of the casing; wherein, the casing includes a first casing structure and a second casing structure, the cell assembly includes a first cell and a second cell, the length of the first cell along a first direction is less than the length of the second cell along the first direction; the first cell includes a first surface and a second surface disposed along the first direction; the first surface and the corresponding side surface of the second cell are flush; the first casing structure and the second casing structure are connected to form a receiving cavity, and the casing forms a stepped surface corresponding to the second surface of the first cell; The positive tabs of both the first and second battery cells are electrically connected to the positive terminal, and the negative tabs of both the first and second battery cells are electrically connected to the negative terminal. The first battery cell includes a single-sided negative electrode sheet near the housing. The single-sided negative electrode sheet includes a first side near the housing and a second side opposite to the first side. The battery also includes a first hot melt adhesive layer located between the first side and the housing. A first adhesive layer is formed on the edge of the single-sided negative electrode sheet corresponding to the first surface. The first adhesive layer includes a portion located between the first battery cell and the housing. The thickness of the first adhesive layer is less than the thickness of the first hot melt adhesive layer.

[0034] As can be seen, in the lithium-ion battery of this application, the first cell and the second cell have different lengths in the first direction. The first surface of the first cell is flush with the corresponding side of the second cell. Therefore, the cell assembly formed by the first cell and the second cell has a stepped shape on one side of the second surface of the first cell. The cell assembly is located in the receiving cavity of the housing, and the housing has a stepped surface corresponding to the stepped surface of the cell assembly. The matching of the stepped surface of the housing and the stepped surface of the cell assembly maximizes the utilization of the receiving cavity of the housing, improves the utilization rate of the receiving cavity of the housing, and thus improves the capacity of the lithium-ion battery. The side of the first cell near the housing is a single-sided negative electrode sheet. A first hot melt adhesive layer is provided between the first side of the single-sided negative electrode sheet near the housing and the housing, which can bond the first cell to the housing in the second direction and prevent the first cell from moving. At the same time, a first adhesive layer is provided on the edge of the single-sided negative electrode sheet corresponding to the first surface of the first cell, which can bond the first cell to the housing in the second direction and further improve the stability of the first cell in the housing. In addition, the thickness of the first adhesive layer is less than that of the first hot melt adhesive layer, which can prevent the first adhesive layer from affecting the size of the first cell in the second direction and causing the housing position corresponding to the first adhesive layer to exceed the limit. Moreover, the edge expansion of the electrode of the stacked cell is more severe. If the thickness of the first adhesive layer is too thick, it is easy for the first adhesive layer to squeeze the housing. The housing is generally harder, which will have a reverse effect on the electrode, thus causing the electrode to shed powder. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A cross-sectional schematic diagram of a lithium-ion battery provided in an embodiment of this application. Figure 1 ;

[0037] Figure 2 for Figure 1 A magnified view of the area within the dashed box;

[0038] Figure 3 A cross-sectional schematic diagram of a lithium-ion battery provided in an embodiment of this application. Figure 2 ;

[0039] Figure 4 A cross-sectional schematic diagram of a lithium-ion battery provided in an embodiment of this application. Figure 3 ;

[0040] Figure 5 A cross-sectional schematic diagram of a lithium-ion battery provided in an embodiment of this application. Figure 4 ;

[0041] Figures 6 to 17 This is a schematic diagram showing the different arrangement positions of the positive and negative terminals on the casing of the lithium-ion battery provided in the embodiments of this application;

[0042] Figure 18 This is a side view of a lithium-ion battery provided in an embodiment of this application;

[0043] Figures 19 to 30 This application provides a schematic diagram showing the different placement positions of the positive and negative tabs of the first and second cells in a lithium-ion battery, according to an embodiment of the application.

[0044] Figure 31 This is a schematic diagram of the positive electrode post placement structure of a lithium-ion battery provided in an embodiment of this application. Figure 1 ;

[0045] Figure 32 This is a schematic diagram of the positive electrode post placement structure of a lithium-ion battery provided in an embodiment of this application. Figure 2 ;

[0046] Figure 33 This is a schematic diagram of the negative electrode post placement structure of a lithium-ion battery provided in an embodiment of this application. Figure 1 ;

[0047] Figure 34 This is a schematic diagram of the negative electrode post placement structure of a lithium-ion battery provided in an embodiment of this application. Figure 1 ;

[0048] Figure 35 This application provides a schematic diagram of the stacking of a first cell and a second cell in a lithium-ion battery. Figure 1 ;

[0049] Figure 36 This application provides a schematic diagram of the stacking of a first cell and a second cell in a lithium-ion battery. Figure 2 ;

[0050] In the diagram, 1. Battery cell assembly; 2. Housing; 3. Positive terminal; 4. Negative terminal; 5. First hot melt adhesive layer; 6. First adhesive layer; 7. Second hot melt adhesive layer; 8. Metal strip; 9. Insulating protective layer; 10. Positive terminal insulating pad; 11. First battery cell; 12. Second battery cell; 13. Third battery cell; 14. Fourth battery cell; 15. Conductive metal; 16. Adhesive layer; 17. Positive tab; 18. Negative tab; 21. First housing structure; 22. Second housing structure; 111. First surface; 112. Second surface; 211. First side surface; 212. Second side, 221, Third side, 222, Fourth side, 2111, First section, 2112, Second section, 2113, Third section, 2121, Fourth section, 2122, Fifth section, 2123, Sixth section, 2211, Seventh section, 2212, Eighth section, 2213, Ninth section, 2124, Tenth section, 2125, Eleventh section, 2126, Twelfth section, 2127, Thirteenth section, 2221, Fourteenth section, 2222, Fifteenth section, 2223, Sixteenth section. Detailed Implementation

[0051] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0052] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0053] As mentioned in the background section, the casing of current lithium-ion batteries is irregularly shaped, while the cell is usually regularly shaped, resulting in low utilization of the internal space of the casing and thus low battery capacity.

[0054] In view of this, this application provides a lithium-ion battery, please refer to... Figures 1 to 4 The device includes a housing 2, a battery cell assembly 1, and a positive terminal post 3 located on the outer surface of the housing 2. The housing 2 includes a first housing structure 21 and a second housing structure 22. The battery cell assembly 1 includes a first battery cell 11 and a second battery cell 12. The length L1 of the first battery cell 11 along the first direction X is less than the length L2 of the second battery cell 12 along the first direction X. The first battery cell 11 includes a first surface 111 and a second surface 112 disposed along the first direction X. The corresponding sides of the first surface and the second battery cell 12 are flush.

[0055] The first housing structure 21 and the second housing structure 22 are connected to form a receiving cavity, and the housing 2 has a stepped surface corresponding to the second surface of the first battery cell 11;

[0056] The positive tabs of the first battery cell 11 and the second battery cell 12 are both electrically connected to the positive terminal 3, and the negative tabs of the first battery cell 11 and the second battery cell 12 are both electrically connected to the negative terminal 4.

[0057] The first cell 11 includes a single-sided negative electrode sheet near the housing 2. The single-sided negative electrode sheet includes a first side near the housing 2 and a second side opposite to the first side. The battery also includes a first hot melt adhesive layer 5 located between the first side and the housing 2. A first adhesive layer 6 is formed on the edge of the single-sided negative electrode sheet corresponding to the first side. The first adhesive layer 6 includes a portion located between the first cell 11 and the housing 2. The thickness d1 of the first adhesive layer 6 is less than the thickness d2 of the first hot melt adhesive layer 5.

[0058] The casing 2 can be made of steel. Steel has high hardness, which can reduce the risk of damage to the lithium-ion battery and improve the heat dissipation of the lithium-ion battery during charging and discharging.

[0059] First cell 11 and second cell 12 are stacked in the second direction Y. Both first cell 11 and second cell 12 can be laminated cells. A laminated cell includes a positive electrode, a negative electrode, and a separator. The positive electrode and the negative electrode are alternately stacked in the second direction Y, and the separator is located between the positive electrode and the negative electrode.

[0060] The positive electrode includes a positive current collector and a positive active material layer on the surface of the positive current collector. When there are negative electrodes on both sides of the positive electrode, the positive active material layer is provided on both opposite surfaces of the positive current collector, and the positive electrode is a double-sided positive electrode. When there is only a negative electrode on one side of the positive electrode, the positive active material layer is provided only on the surface of the positive current collector opposite to the negative electrode, and the positive electrode is a single-sided positive electrode. The single-sided positive electrode is located at the end of the laminated cell in the second direction Y.

[0061] The negative electrode includes a negative current collector and a layer of negative active material on the surface of the negative current collector. When there are positive electrodes on both sides of the negative electrode, the negative active material layer is provided on both opposite surfaces of the negative current collector, and the negative electrode is a double-sided negative electrode. When there is a positive electrode on only one side of the negative electrode, the negative active material layer is provided only on the surface of the negative current collector opposite to the positive electrode, and the negative electrode is a single-sided negative electrode. The single-sided negative electrode is located at the end of the laminated cell in the second direction Y.

[0062] It should be noted that in this embodiment, the number of battery cells in battery cell assembly 1 is at least two, but the specific number is not limited and can be set by the user.

[0063] For example, such as Figure 3 As shown, in addition to the first battery cell 11 and the second battery cell 12, a third battery cell 13 may also be included. The length L3 of the third battery cell 13 along the first direction X is less than the length L2 of the second battery cell 12 along the first direction X. The third battery cell 13 and the first battery cell 11 may be located on opposite sides of the second battery cell 12 in the second direction Y. In this case, the battery cell assembly 1 has three steps, and the housing 2 is provided with a stepped surface that matches the battery cell assembly 1. Alternatively, the length L3 of the third battery cell 13 along the first direction X is greater than the length L2 of the second battery cell 12 along the first direction X. The third battery cell 13 and the first battery cell 11 are located on opposite sides of the second battery cell 12 in the second direction Y, and the housing 2 is provided with a stepped surface that matches the battery cell assembly 1.

[0064] For example, such as Figure 4 As shown, in addition to the first battery cell 11 and the second battery cell 12, it may also include a third battery cell 13 and a fourth battery cell 14. The length L3 of the third battery cell 13 along the first direction X is greater than the length L2 of the second battery cell 12 along the first direction X, and the length L4 of the fourth battery cell 14 along the first direction X is less than the length L3 of the third battery cell 13 along the first direction X. The third battery cell 13 and the first battery cell 11 are respectively located on opposite sides of the second battery cell 12 in the second direction Y, and the second battery cell 12 and the fourth battery cell 14 are respectively located on opposite sides of the third battery cell 13 in the second direction Y. At this time, the battery cell assembly 1 has four steps, and the housing 2 is provided with step surfaces that match the battery cell assembly 1.

[0065] In this embodiment, the distribution position of the first adhesive layer 6 is not specifically limited. The first adhesive layer 6 is at least disposed in the edge area of ​​the first side of the single-sided negative electrode sheet, that is, the first adhesive layer 6 is at least disposed between the first cell 11 and the shell 2.

[0066] In this embodiment, the thicknesses of the first adhesive layer 6 and the first hot melt adhesive layer 5 are not limited and can be set by the user. For example, the thickness d1 of the first adhesive layer 6 can be 8 micrometers to 20 micrometers, and the thickness d2 of the first hot melt adhesive layer 5 can be 10 micrometers to 40 micrometers.

[0067] In one embodiment of this application, the second cell 12 includes a single-sided negative electrode sheet near the housing 2. The single-sided negative electrode sheet includes a third side near the housing 2 and a fourth side disposed opposite to the third side. The battery also includes a third hot melt adhesive layer located between the third side and the housing 2. A second adhesive layer is formed on the edge of the corresponding third side of the single-sided negative electrode sheet. The second adhesive layer includes a portion located between the second cell 12 and the housing 2. The thickness of the second adhesive layer is less than that of the third hot melt adhesive layer between the third side and the housing 2.

[0068] A third hot melt adhesive layer is provided between the third side of the single-sided negative electrode sheet in the second cell 12 and the shell 2, which can bond the second cell 12 to the shell 2 and prevent the second cell 12 from moving.

[0069] A second adhesive layer is provided at the edge of the third surface of the single-sided negative electrode sheet, which can bond the second cell 12 and the housing 2 in the second direction Y, further improving the stability of the second cell 12 within the housing 2. In addition, the thickness of the second adhesive layer is less than the thickness of the third hot melt adhesive layer, which can prevent the second adhesive layer from affecting the dimensions of the second cell 12 in the second direction Y, causing the housing 2 position corresponding to the second adhesive layer to exceed the limit; moreover, the edge expansion of the electrode sheet of the stacked cell is more severe. If the thickness of the second adhesive layer is too thick, it is easy for the second adhesive layer to squeeze the housing 2. The housing 2 is generally more rigid, which will have a reverse effect on the electrode sheet, resulting in electrode powder shedding.

[0070] It should be noted that the shapes of the first shell structure 21 and the second shell structure 22 are not specifically limited in this embodiment.

[0071] As one possible implementation method, such as Figure 1 As shown, the first shell structure 21 is stepped, and the second shell structure 22 is planar.

[0072] In this embodiment, only the first housing structure 21 is set to a stepped shape to facilitate the entry of the battery cell assembly 1 into the housing 2 and flange welding.

[0073] As another possible implementation method, such as Figure 3 and Figure 4 As shown, both the first shell structure 21 and the second shell structure 22 are stepped.

[0074] In this embodiment, both the first shell structure 21 and the second shell structure 22 are set in a stepped shape, which makes it more flexible to manufacture the first shell structure 21 and the second shell structure 22 with the pit. When there are only two battery cells, the first battery cell 11 and the second battery cell 12, the technical challenge of step-piercing can be reduced. There is no need to punch out the step pit, and a thinner shell 2 can be used.

[0075] It should be noted that in this embodiment, the positions of the positive terminal 3 and the negative terminal 4 on the side of the housing 2 are not limited and can be set by the user.

[0076] In one possible implementation, the positive terminal 3 and the negative terminal 4 are located on the same side of the housing 2.

[0077] As another possible implementation, the positive terminal 3 and the negative terminal 4 are located on two opposite sides of the housing 2.

[0078] It should also be noted that when the positive terminal 3 and the negative terminal 4 are located on the same side of the housing 2, the present application does not limit the position of the positive terminal 3 and the negative terminal 4 on the housing 2.

[0079] As one possible implementation, both the positive terminal 3 and the negative terminal 4 are located in the first housing structure 21.

[0080] As another possible implementation, both the positive terminal 3 and the negative terminal 4 are located in the second housing structure 22.

[0081] It should be noted that this application does not limit the number of positive terminal 3 and negative terminal 4, and they can be set by the user.

[0082] In one possible implementation, there is one positive terminal 3 and one negative terminal 4. The positive terminals of the first battery cell 11 and the second battery cell 12 are both electrically connected to the positive terminal 3, and the negative terminals of the first battery cell 11 and the second battery cell 12 are both electrically connected to the negative terminal 4.

[0083] The positive terminal 3 and the negative terminal 4 can be located on the same side of the housing 2 or on different sides of the housing 2, and this application does not limit them.

[0084] In this embodiment, the first battery cell 11 and the second battery cell 12 share the positive terminal 3 and the negative terminal 4, which can reduce the number of positive terminal 3 and negative terminal 4 and reduce manufacturing costs.

[0085] In one possible implementation, there are two positive terminals 3 and one negative terminal 4. The positive terminals of the first cell 11 are electrically connected to both positive terminals 3, the positive terminals of the second cell 12 are electrically connected to both positive terminals 3, and the negative terminals of the first cell 11 and the second cell 12 are electrically connected to the negative terminal 4.

[0086] In one possible implementation, there are two positive terminals 3 and one negative terminal 4. The positive terminal of the first cell 11 is electrically connected to one positive terminal 3, and the positive terminal of the first cell 11 is electrically connected to the other positive terminal 3. The negative terminals of the first cell 11 and the second cell 12 are both electrically connected to the negative terminal 4.

[0087] When there are two positive electrode posts 3, compared to when there is only one positive electrode post 3, there is one more positive electrode post 3, which reduces the current and thus reduces the impedance of the cell assembly 1, improving the dynamic performance of the battery. At the same time, it can also reduce the current density of the positive electrode post 3 on one side, improving the overload capacity of the tab under high current density of the cell assembly 1.

[0088] The two positive terminals 3 can be located on the same side of the housing 2, and the negative terminal 4 can be on the same side as the two positive terminals 3, or not on the same side. Of course, the two positive terminals 3 and the one negative terminal 4 can also be located on different sides of the housing 2.

[0089] If the thickness allows, the positive terminal 3 or the negative terminal 4 can be placed on the side of the corresponding first cell 11.

[0090] In this embodiment, the first cell 11 and the second cell 12 in the lithium-ion battery have different lengths in the first direction X. The first surface of the first cell 11 is flush with the corresponding side of the second cell 12. Therefore, the cell assembly 1 formed by the first cell 11 and the second cell 12 is stepped on one side of the second surface of the first cell 11. The cell assembly 1 is located in the receiving cavity of the housing 2, and the housing 2 has a stepped surface corresponding to the stepped surface of the cell assembly 1. The matching of the stepped surface of the housing 2 with the stepped surface of the cell assembly 1 maximizes the utilization of the receiving cavity of the housing 2, improves the utilization rate of the receiving cavity of the housing 2, and thus increases the capacity of the lithium-ion battery. The first cell 11 has a single-sided negative electrode sheet on the side near the housing 2. A first hot melt adhesive layer 5 is provided between the first side of the single-sided negative electrode sheet near the housing 2 and the housing 2, which can bond the first cell 11 to the housing 2 in the second direction Y, preventing the first cell 11 from shifting. At the same time, a first adhesive layer 6 is provided on the edge of the first surface of the single-sided negative electrode sheet corresponding to the first cell 11, which can bond the first cell 11 to the housing 2 in the second direction Y, further improving the stability of the first cell 11 within the housing 2. In addition, the thickness of the first adhesive layer 6 is less than the thickness of the first hot melt adhesive layer 5, which can prevent the first adhesive layer 6 from affecting the size of the first cell 11 in the second direction Y, causing the position of the first adhesive layer 6 in the housing 2 to exceed the limit. Moreover, the edge expansion of the electrode sheet of the stacked cell is more severe. If the thickness of the first adhesive layer 6 is too thick, it is easy for the first adhesive layer 6 to squeeze the housing 2. The housing 2 is generally hard, which will have a reverse effect on the electrode sheet, resulting in electrode powder shedding.

[0091] Based on the above embodiments, in one embodiment of this application, the first adhesive layer 6 extends from the first side of the single-sided negative electrode sheet to the second cell 12, and / or the first cell 11 includes a positive electrode sheet, a separator and a negative electrode sheet, the separator includes a first portion extending from the negative electrode sheet along the first direction X, and the projection of the first adhesive layer 6 in the second direction Y overlaps with the projection of the first portion.

[0092] When the first adhesive layer 6 extends from the first side of the single-sided negative electrode sheet to the second cell 12, it can bond the first cell 11 and the second cell 12 to the housing 2 in the first direction X, thereby improving the stability of the first cell 11 and the second cell 12 in the housing cavity of the housing 2 and preventing movement.

[0093] The projection of the first adhesive layer 6 in the second direction Y overlaps with the projection of the first part of the diaphragm, that is, the first adhesive layer 6 is also distributed in the first part of the diaphragm. The first adhesive layer 6 bonds and fixes the first part of the diaphragm that extends out, which can prevent the diaphragm from thermally running away and shrinking inward, and can also prevent the diaphragm from moving back and forth.

[0094] like Figure 5 As shown, based on any of the above embodiments, in one embodiment of this application, the second cell 12 includes a first electrode near the first cell 11, and the first adhesive layer 6 extends from the first side of the single-sided negative electrode to the first electrode.

[0095] In another embodiment, the first electrode and the housing 2 are bonded and fixed together by a second hot melt adhesive layer 7. In a further embodiment, a gap is left between the second hot melt adhesive layer 7 and the first adhesive layer 6.

[0096] The first electrode can be a negative electrode. The first electrode and the housing 2 are bonded and fixed together by the second hot melt adhesive layer 7, which can improve the stability of the second cell 12 in the housing cavity and prevent the second cell 12 from moving around.

[0097] A gap is left between the second hot melt adhesive layer 7 and the first adhesive layer 6 to prevent the second hot melt adhesive layer 7 and the first adhesive layer 6 from overlapping and becoming too thick, which would affect the energy density of the lithium-ion battery.

[0098] Based on the above embodiments, in one embodiment of this application, when the first housing structure 21 is stepped and the second housing structure 22 is planar, the first housing structure 21 includes a first side 211 and a second side 212 opposite to each other; the first side 211 is opposite to the target side of the cell assembly 1, and the target side is the surface flush with the first cell 11 and the second cell 12, and the positive terminal 3 and the negative terminal 4 are both located on the first side 211 or the second side 212, or one of the positive terminal 3 and the negative terminal 4 is located on the first side 211 and the other is located on the second side 212.

[0099] In this embodiment, the positive terminal 3 and the negative terminal 4 can be arranged as follows: both the positive terminal 3 and the negative terminal 4 are located on the first side 211 of the first housing 2; or both the positive terminal 3 and the negative terminal 4 are located on the second side 212 of the first housing 2; or the positive terminal 3 is located on the first side 211 of the first housing 2 and the negative terminal 4 is located on the second side 212 of the first housing 2; or the positive terminal 3 can be located on the second side 212 of the first housing 2 and the negative terminal 4 can be located on the first side 211 of the first housing 2.

[0100] The shapes of the first housing structure 21 and the second housing structure 22, as well as the specific locations of the positive terminal 3 and the negative terminal 4, are described in the following embodiments.

[0101] Based on the above embodiments, in one embodiment of this application, the first housing structure 21 and the second housing structure 22 are both stepped. The second housing structure 22 includes a third side 221 and a fourth side 222 that are opposite to each other. The third side 221 is opposite to the target side of the battery cell assembly 1. The positive terminal 3 and the negative terminal 4 are both located on the third side 221 or the fourth side 222, or one of the positive terminal 3 and the negative terminal 4 is located on the third side 221 and the other is located on the fourth side 222.

[0102] In this embodiment, the positive terminal 3 and the negative terminal 4 can be arranged as follows: both the positive terminal 3 and the negative terminal 4 are located on the third side 221 of the second housing 2; or both the positive terminal 3 and the negative terminal 4 are located on the fourth side 222 of the second housing 2; or the positive terminal 3 is located on the first side 211 of the second housing 2 and the negative terminal 4 is located on the second side 212 of the first housing 2; or the positive terminal 3 can be located on the second side 212 of the second housing 2 and the negative terminal 4 can be located on the first side 211 of the second housing 2.

[0103] The shapes of the first housing structure 21 and the second housing structure 22, as well as the specific locations of the positive terminal 3 and the negative terminal 4, are described in the following embodiments.

[0104] like Figure 6 As shown, in one embodiment of this application, the first side surface 211 is a surface extending along the second direction Y, the second side surface 212 is stepped, the positive electrode post 3 and the negative electrode post 4 are both located on the first side surface 211, and the second direction Y is perpendicular to the first direction X.

[0105] like Figure 7As shown, in one embodiment of this application, both the first side 211 and the second side 212 are stepped. The first side 211 includes at least a first partition 2111 and a second partition 2112 extending along the second direction Y, and a third partition 2113 extending along the first direction X. The first partition 2111 and the second partition 2112 are offset along the first direction X, and the third partition 2113 connects the first partition 2111 and the second partition 2112. The positive terminal 3 and the negative terminal 4 are both located in the third partition 2113.

[0106] like Figures 8 to 10 As shown, in one embodiment of this application, the first side surface 211 is a surface extending along the second direction Y, the second side surface 212 is stepped, and the second side surface 212 includes at least a fourth partition 2121 and a fifth partition 2122 extending along the second direction Y, and a sixth partition 2123 extending along the first direction X. The fourth partition 2121 and the fifth partition 2122 are offset along the first direction X, and the sixth partition 2123 connects the fourth partition 2121 and the fifth partition 2122. The positive terminal 3 and the negative terminal 4 are both located in the fourth partition 2121 or both are located in the sixth partition 2123, or one of the positive terminal 3 and the negative terminal 4 is located in the first side surface 211 and the other is located in the fourth partition 2121.

[0107] like Figures 11 to 12 As shown, in one embodiment of this application, the third side 221 and the fourth side 222 are both surfaces extending along the second direction Y, and the positive electrode post 3 and the negative electrode post 4 are both located on the third side 221 or both on the fourth side 222.

[0108] like Figure 13 As shown, in one embodiment of this application, the third side 221 includes at least a seventh partition 2211 and an eighth partition 2212 extending along the second direction Y, and a ninth partition 2213 extending along the first direction X. The seventh partition 2211 and the eighth partition 2212 are offset along the first direction X, and the ninth partition 2213 connects the seventh partition 2211 and the eighth partition 2212. The positive terminal 3 and the negative terminal 4 are both located in the ninth partition 2213.

[0109] like Figure 14 As shown, in one embodiment of this application, the third side 221 and the fourth side 222 are both surfaces extending along the second direction Y. The second side 212 of the first housing structure 21 includes at least a tenth partition 2124 extending along the first direction X and an eleventh partition 2125 extending along the second direction Y. The positive terminal 3 and the negative terminal 4 are both located in the tenth partition 2124.

[0110] like Figure 15As shown, in one embodiment of this application, the first side 211 includes a first partition 2111 and a second partition 2112 extending along the second direction Y, and a third partition 2113 extending along the first direction X. The first partition 2111 and the second partition 2112 are offset along the first direction X, and the third partition 2113 connects the first partition 2111 and the second partition 2112. The second side 212 includes a fourth partition 2121, a fifth partition 2122 and a twelfth partition 2126 extending along the second direction Y, and a sixth partition 2123 and a thirteenth partition 2127 extending along the first direction X. The fourth partition 2121, the fifth partition 2122 and the twelfth partition 2126 are offset along the first direction X, and the thirteenth partition 2127 connects the fifth partition 2122 and the twelfth partition 2126. One of the positive terminal 3 and the negative terminal 4 is located in the second partition 2112, and the other is located in the sixth partition 2123.

[0111] like Figure 16 As shown, in one embodiment of this application, the third side 221 and the fourth side 222 are both surfaces extending along the second direction Y, and one of the positive electrode post 3 and the negative electrode post 4 is located on the third side 221 and the other is located on the fourth side 222.

[0112] like Figure 17 As shown, in one embodiment of this application, the third side 221 includes at least a seventh partition 2211 and an eighth partition 2212 extending along the second direction Y, and a ninth partition 2213 extending along the first direction X. The seventh partition 2211 and the eighth partition 2212 are offset along the first direction X, and the ninth partition 2213 connects the seventh partition 2211 and the eighth partition 2212. The fourth side 222 includes at least a fourteenth partition 2221 and a fifteenth partition 2222 extending along the second direction Y, and a sixteenth partition 2223 extending along the first direction X. The fourteenth partition 2221 and the fifteenth partition 2222 are offset along the first direction X, and the sixteenth partition 2223 connects the fourteenth partition 2221 and the fifteenth partition 2222. One of the positive terminal 3 and the negative terminal 4 is located in the ninth partition 2213, and the other is located in the sixteenth partition 2223.

[0113] Based on any of the above embodiments, in one embodiment of this application, the positive tab 17 and negative tab 18 of the first battery cell 11 and the second battery cell 12 are both located in the target area of ​​the same target side of the battery cell assembly 1. The target side is the side of the first battery cell 11 and the second battery cell 12 that is flush with each other, and the target area is the area where the projections of the first battery cell 11 and the second battery cell 12 overlap on the horizontal plane.

[0114] In this embodiment, the shapes of the first battery cell 11 and the second battery cell 12 are not limited and can be determined as appropriate. For example, the first battery cell 11 and the second battery cell 12 can both be regular shapes, such as rectangles, or the first battery cell 11 can be a regular shape and the second battery cell 12 can be an irregular shape.

[0115] like Figures 18 to 20 As shown, the first battery cell 11 and the second battery cell 12 can have three flush sides P1, P2, and P3. The positive electrode tab 17 and the negative electrode tab 18 of the first battery cell 11 and the second battery cell 12 are located in the target area of ​​the upper flush side. Among them, Figure 18 for Figure 19 Side view of the battery shown.

[0116] like Figures 21 to 24 As shown, the first battery cell 11 and the second battery cell 12 may have a flush side surface P1, and the positive electrode tab 17 and the negative electrode tab 18 of the first battery cell 11 and the second battery cell 12 are located in the target area of ​​the flush side surface above.

[0117] like Figure 19 , Figure 21 , Figure 23 As shown, the housing 2 can reserve space only in the areas corresponding to the positive tab 17 and the negative tab 18, and further compress in other areas of the cell assembly 1, thereby improving the energy density of the lithium-ion battery.

[0118] Based on any of the above embodiments, in one embodiment of this application, the positive tab 17 and negative tab 18 of the first battery cell 11 and the second battery cell 12 are located on any side of the battery cell assembly 1 other than the target side, and the positive tab 17 and negative tab 18 of the first battery cell 11 and the positive tab 17 and negative tab 18 of the second battery cell 12 are located on the same side.

[0119] like Figure 25 As shown, the first battery cell 11 and the second battery cell 12 can have three flush sides. The positive electrode 17 and negative electrode 18 of the first battery cell 11 are located on side N1 other than the target side, and the positive electrode 17 and negative electrode 18 of the second battery cell 12 are located on side N2 other than the target side. The negative electrode 18 of the first battery cell 11 and the negative electrode 18 of the second battery cell 12 are welded to the housing 2, respectively. The positive electrode 17 of the first battery cell 11 and the positive electrode 17 of the second battery cell 12 are welded together by a surface-insulated metal strip 8 (e.g., aluminum strip). The metal strip 8 is connected to the surfaces of the first battery cell 11 and the second battery cell 12 and is insulated. The metal strip 8 is welded to the positive terminal 3.

[0120] like Figure 26 , Figure 27As shown, the first battery cell 11 and the second battery cell 12 may have a flush side. The positive electrode 17 and negative electrode 18 of the first battery cell 11 are located on any side other than the target side, and the positive electrode 17 and negative electrode 18 of the second battery cell 12 are located on any side other than the target side. The negative electrode 18 of the first battery cell 11 and the negative electrode 18 of the second battery cell 12 are respectively welded to the housing 2. The positive electrode 17 of the first battery cell 11 and the positive electrode 17 of the second battery cell 12 are welded through a surface-insulated metal strip 8 (e.g., aluminum strip). The metal strip 8 is connected to the surface of the first battery cell 11 and the second battery cell 12 for insulation treatment, and the metal strip 8 is welded to the positive terminal 3.

[0121] exist Figure 26 In the example shown, the positive tab 17 and negative tab 18 of the first battery cell 11 are located on the side N6, and the positive tab 17 and negative tab 18 of the second battery cell 12 are located on the side N3. It can be understood that the positive tab 17 and negative tab 18 of the first battery cell 11 can also be located on the side N4, and the positive tab 17 and negative tab 18 of the second battery cell 12 can be located on the side N1; or, the positive tab 17 and negative tab 18 of the first battery cell 11 can also be located on the side N5, and the positive tab 17 and negative tab 18 of the second battery cell 12 can be located on the side N2.

[0122] Similarly, in Figure 27 In the first battery cell 11, the positive electrode 17 and the negative electrode 18 can also be located on the side N14, and the positive electrode 17 and the negative electrode 18 of the second battery cell 12 can be located on the side N11; or, the positive electrode 17 and the negative electrode 18 of the first battery cell 11 can also be located on the sides N12, N13, and N14, and the positive electrode 17 and the negative electrode 18 of the second battery cell 12 can be located on the sides N1, N16, and N11 respectively.

[0123] Based on any of the above embodiments, in one embodiment of this application, one of the positive tabs 17 and negative tabs 18 of the first battery cell 11 and the second battery cell 12 is located in the target area of ​​the target side, and the other tab is located on any side other than the target side.

[0124] like Figure 28 As shown, the first battery cell 11 and the second battery cell 12 may have three flush sides P1, P2, and P3. The positive electrode tab 17 of the first battery cell 11 and the positive electrode tab 17 of the second battery cell 12 are located in the target area of ​​one target side. The negative electrode tab 18 of the first battery cell 11 is located on side N4 other than the target side, and the negative electrode tab 18 of the second battery cell 12 is located on side N2 other than the target side. The negative electrode tabs 18 of the first battery cell 11 and the second battery cell 12 are respectively welded to the housing 2.

[0125] like Figure 29As shown, the first battery cell 11 and the second battery cell 12 may have a flush side surface P1. The positive electrode tabs 17 of the first battery cell 11 and the second battery cell 12 are located in the target area of ​​the target side surface. The negative electrode tab 18 of the first battery cell 11 is located on a side surface other than the target side surface (e.g., N4, N5, N6), and the negative electrode tab 18 of the second battery cell 12 is located on a side surface other than the target side surface (e.g., N1, N2, N3). The positive electrode tabs 17 of the first battery cell 11 and the second battery cell 12 can be connected to the positive terminal 3 via a metal strip 8. The negative electrode tabs 18 of the first battery cell 11 and the second battery cell 12 are respectively welded to the housing 2.

[0126] like Figure 30 As shown, the first battery cell 11 and the second battery cell 12 may have a flush side surface P1. The positive electrode tabs 17 of the first battery cell 11 and the second battery cell 12 are located in the target area of ​​the target side surface. The negative electrode tab 18 of the first battery cell 11 is located on a side surface other than the target side surface (e.g., N12, N13, N14), and the negative electrode tab 18 of the second battery cell 12 is located on a side surface other than the target side surface (e.g., N1, N6, N11). The positive electrode tabs 17 of the first battery cell 11 and the second battery cell 12 can be connected to the positive terminal 3 via a metal strip 8. The negative electrode tabs 18 of the first battery cell 11 and the second battery cell 12 are respectively welded to the housing 2.

[0127] exist Figures 28 to 30 In the middle, the positions of the positive electrode 17 and the negative electrode 18 can be interchanged. One type of electrode is placed on the side flush with the top, and the other type of electrode is placed on the other side, which can reduce the space above the head.

[0128] Based on any of the above embodiments, in one embodiment of this application, the first battery cell 11 and the second battery cell 12 include stacked battery cells, the positive electrode tab 17 includes a first electrode tab and a second electrode tab that are electrically connected, the first electrode tab and the positive current collector in the stacked battery cell are integrated into a single structure, and the second electrode tab is electrically connected to the positive electrode post 3.

[0129] The negative electrode 18 includes a third electrode and a fourth electrode that are electrically connected. The third electrode and the negative current collector in the laminated battery cell are integrated into one structure, and the fourth electrode is electrically connected to the negative electrode post 4.

[0130] An insulating protective layer 9 is located on the outer surface of the first tab of all the collections; and / or, on the outer surface of the third tab of all the collections.

[0131] The insulating protective layer 9 can prevent the first tab and / or the third tab from accidentally contacting the conductive parts of the battery (such as the casing 2 or other conductive parts) and causing a short circuit; it also protects and buffers the first tab and / or the third tab, preventing deformation and damage.

[0132] It should be noted that in the first cell 11, each layer of positive current collector has a first tab, and each layer of negative current collector has a third tab; in the second cell 12, each layer of positive current collector has a first tab, and each layer of negative current collector has a third tab.

[0133] like Figure 31 As shown, the positive terminal 3 is located in the tenth section 2124 of the first housing structure 21 and is internally connected to the conductive metal 15 inside the first housing structure 21. The positive terminal insulating pad 10 is provided on the inner side of the first housing structure 21, and the positive terminal tab 17 is electrically connected to the positive terminal 3 through the metal strip 8.

[0134] like Figure 32 As shown, the positive terminal 3 is located on the first side 211 of the first housing structure 21 and is internally connected to the conductive metal 15 inside the first housing structure 21. The positive terminal insulating pad 10 is provided on the inner side of the first housing structure 21, and the negative terminal tab 18 is electrically connected to the negative terminal 4 through the metal strip 8.

[0135] like Figure 33 As shown, the negative electrode post 4 is located in the tenth section 2124 of the first housing structure 21 and is internally connected to the conductive metal 15 inside the first housing structure 21. The inner side of the first housing structure 21 is provided with an insulating pad 10 for the negative electrode post 4. The negative electrode tab 18 is electrically connected to the negative electrode post 4 through a metal strip 8 (e.g., a nickel strip).

[0136] like Figure 34 As shown, the negative electrode post 4 is located on the first side 211 of the first housing structure 21 and is internally connected to the conductive metal 15 inside the first housing structure 21. The inner side of the first housing structure 21 is provided with an insulating pad 10 for the negative electrode post 4. The negative electrode tab 18 is electrically connected to the negative electrode post 4 through a metal strip 8 (e.g., a nickel strip).

[0137] Based on any of the above embodiments, in one embodiment of this application, the first battery cell 11 and the second battery cell 12 have active material layers distributed at least in the stacked contact area; or, the first battery cell 11 and the second battery cell 12 have adhesive layers 16 distributed in the stacked contact area. The adhesive layer 16 can be double-sided adhesive.

[0138] Battery cell assembly 1 can be stacked continuously, such as Figure 35 As shown, the entire surface of the topmost electrode of the second cell 12 is covered with an active material layer, meaning that there is also an active material layer in the non-contact area Q, or... Figure 35 As shown, the uppermost electrode of the second cell 12 has an active material layer only in the contact area with the first cell 11, and there is no active material layer in the non-contact area Q.

[0139] The first battery cell 11 and the second battery cell 12 can also be stacked separately, such as Figure 36 As shown, the first battery cell 11 and the second battery cell 12 are bonded together using an adhesive layer 16.

[0140] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0141] The lithium-ion battery provided in this application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the solution and core ideas of this application. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of this application.

Claims

1. A lithium-ion battery, characterized in that, The device includes a housing, a battery cell assembly, and a positive electrode post located on the outer surface of the housing. The housing includes a first housing structure and a second housing structure. The battery cell assembly includes a first battery cell and a second battery cell. The length of the first battery cell along a first direction is less than the length of the second battery cell along the first direction. The first battery cell includes a first surface and a second surface disposed along the first direction. The first surface and the corresponding side surface of the second battery cell are flush. The first housing structure and the second housing structure are connected to form a receiving cavity, and the housing has a stepped surface corresponding to the second surface of the first battery cell; The positive tabs of the first battery cell and the second battery cell are both electrically connected to the positive terminal, and the negative tabs of the first battery cell and the second battery cell are both electrically connected to the negative terminal. The first cell includes a single-sided negative electrode sheet near the housing. The single-sided negative electrode sheet includes a first side near the housing and a second side opposite to the first side. The battery also includes a first hot melt adhesive layer located between the first side and the housing. The edge of the single-sided negative electrode sheet corresponding to the first side is formed with a first adhesive layer. The first adhesive layer includes a portion located between the first cell and the housing. The thickness of the first adhesive layer is less than the thickness of the first hot melt adhesive layer.

2. The lithium-ion battery as described in claim 1, characterized in that, The first adhesive layer extends from the first side of the single-sided negative electrode sheet to the second cell, and / or the first cell includes a positive electrode sheet, a separator, and a negative electrode sheet, the separator including a first portion extending out of the negative electrode sheet along a first direction, and the projection of the first adhesive layer in a second direction overlaps with the projection of the first portion.

3. The lithium-ion battery as described in claim 1, characterized in that, The second cell includes a first electrode near the first cell, and the first adhesive layer extends from the first side of the single-sided negative electrode to the first electrode; and / or, The first electrode and the housing are bonded and fixed together by a second hot melt adhesive layer; And / or, A gap is left between the second hot melt adhesive layer and the first adhesive layer.

4. The lithium-ion battery as described in claim 1, characterized in that, The first shell structure is stepped, and the second shell structure is planar; or, both the first shell structure and the second shell structure are stepped.

5. The lithium-ion battery as described in claim 1, characterized in that, The battery includes a positive terminal and a negative terminal, which are located on the same side of the housing; or, the positive terminal and the negative terminal are located on two opposite sides of the housing. And / or, the positive terminal and the negative terminal are both located in the first housing structure or both are located in the second housing structure.

6. The lithium-ion battery as described in claim 5, characterized in that, The first housing structure is stepped, and the second housing structure is planar. The first housing structure includes opposing first and second side surfaces. The first side surface is opposite to the target side surface of the battery cell assembly. The target side surface is a surface flush with both the first and second battery cells. The positive terminal and the negative terminal are both located on the first side surface or the second side surface, or one of the positive terminal and the negative terminal is located on the first side surface and the other is located on the second side surface; or... Both the first housing structure and the second housing structure are stepped. The second housing structure includes a third side and a fourth side facing each other. The third side is opposite to the target side of the battery cell assembly. The positive terminal and the negative terminal are both located on the third side or the fourth side, or one of the positive terminal and the negative terminal is located on the third side and the other is located on the fourth side.

7. The lithium-ion battery as described in claim 6, characterized in that, The first side surface is a surface extending along the second direction, the second side surface is stepped, and both the positive and negative terminals are located on the first side surface. The second direction is perpendicular to the first direction; or... Both the first and second sides are stepped. The first side includes at least a first and a second partition extending along a second direction, and a third partition extending along a first direction. The first and second partitions are staggered along the first direction. The third partition connects the first and second partitions. The positive and negative terminals are both located in the third partition. Alternatively, The first side is a surface extending along a second direction, and the second side is stepped. The second side includes at least a fourth and a fifth section extending along the second direction, and a sixth section extending along a first direction. The fourth and fifth sections are staggered along the first direction, and the sixth section connects the fourth and fifth sections. The positive and negative terminals are both located in the fourth section or both in the sixth section; or, one of the positive and negative terminals is located on the first side, and the other is located in the fourth section. Both the third and fourth side surfaces are surfaces extending along the second direction, and the positive and negative terminals are either both located on the third side surface or both located on the fourth side surface; or... The third side includes at least a seventh and an eighth section extending along a second direction, and a ninth section extending along a first direction. The seventh and eighth sections are offset along the first direction, and the ninth section connects the seventh and eighth sections. Both the positive and negative terminals are located in the ninth section; or... The third side and the fourth side are both surfaces extending along the second direction. The second side of the first housing structure includes at least a tenth section extending along the first direction and an eleventh section extending along the second direction. The positive terminal and the negative terminal are both located in the tenth section. or, The first side includes a first and a second partition extending along a second direction, and a third partition extending along a first direction. The first and second partitions are offset along the first direction, and the third partition connects the first and second partitions. The second side includes a fourth, a fifth, and a twelfth partition extending along a second direction, and a sixth and a thirteenth partition extending along a first direction. The fourth, fifth, and twelfth partitions are offset along the first direction, and the thirteenth partition connects the fifth and twelfth partitions. One of the positive and negative terminals is located in the second partition, and the other is located in the sixth partition; or... Both the third and fourth sides are surfaces extending along the second direction, with one of the positive and negative terminals located on the third side and the other on the fourth side; or... The third side includes at least a seventh and an eighth section extending along a second direction, and a ninth section extending along a first direction. The seventh and eighth sections are offset along the first direction, and the ninth section connects the seventh and eighth sections. The fourth side includes at least a fourteenth and a fifteenth section extending along a second direction, and a sixteenth section extending along a first direction. The fourteenth and fifteenth sections are offset along the first direction, and the sixteenth section connects the fourteenth and fifteenth sections. One of the positive and negative terminals is located in the ninth section, and the other is located in the sixteenth section.

8. The lithium-ion battery as described in claim 1, characterized in that, The positive and negative tabs of the first and second battery cells are both located in the same target area on the same target side of the battery cell assembly. The target side is the side flush with the first and second battery cells, and the target area is the region where the projections of the first and second battery cells overlap on a horizontal plane; or... The positive and negative tabs of both the first and second battery cells are located on any side of the battery cell assembly other than the target side; or, One of the positive and negative tabs of the first and second battery cells is located in the target area on the target side, and the other tab is located on any side other than the target side.

9. The lithium-ion battery as described in claim 1, characterized in that, The first battery cell and the second battery cell include laminated battery cells. The positive electrode includes a first electrode and a second electrode that are electrically connected. The first electrode and the positive current collector in the laminated battery cell are integrally structured. The second electrode is electrically connected to the positive terminal. The negative electrode tab includes a third electrode tab and a fourth electrode tab that are electrically connected. The third electrode tab and the negative electrode current collector in the laminated battery cell are integrated into one structure. The fourth electrode tab is electrically connected to the negative electrode post. An insulating protective layer is located on the outer surface of the first tab of all the collections; and / or, on the outer surface of the third tab of all the collections.

10. The lithium-ion battery according to any one of claims 1 to 9, characterized in that, The first battery cell and the second battery cell have active material layers distributed in at least the stacked contact area; or, the first battery cell and the second battery cell have adhesive layers distributed in the stacked contact area.

Images