Lithium ion battery

Abstract

The lithium ion battery is characterized in that a first battery cell body is accommodated in a first insulating mounting cavity, a first tab and a second tab are connected to the first battery cell body at an interval and extend out of the first insulating mounting cavity from a first side part of a shell, and the polarities of the first tab and the second tab are opposite; the second battery cell body is accommodated in the second insulating mounting cavity, the first tab and the second tab are connected to the second battery cell body at an interval and extend out of the second insulating mounting cavity from the first side part, and the polarities of the third tab and the fourth tab are opposite; in the length direction of the first side part, one of the first tab and the second tab is positioned between the third tab and the fourth tab, and one of the third tab and the fourth tab is positioned between the first tab and the second tab; the distance between the first tab and the second tab and the distance between the third tab and the fourth tab are increased as much as possible under the limitation of the size of the battery cell, so that the condition of short circuit of the battery cell caused by contact in the production or transfer process is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a lithium-ion battery. Background Art

[0002] A lithium-ion battery refers to a lithium-ion battery containing lithium (including metallic lithium, lithium alloy, lithium ions, and lithium polymer) in an electrochemical system. In recent years, due to many advantages such as long cycle life, good safety performance, and fast charge and discharge, lithium-ion batteries have been widely used in fields such as digital products, electric vehicles, and energy storage systems.

[0003] A lithium-ion battery includes a packaging bag and a plurality of battery cells. The plurality of battery cells are arranged in the packaging bag along the thickness direction of the battery. A tab is welded to the battery cell, and the tab penetrates out of the packaging bag. To facilitate the connection of the tabs, the tabs of the plurality of battery cells in the existing lithium-ion battery all extend to the same side of the packaging bag, and the two tabs of each battery cell are arranged adjacent to each other. Since the width of the side of the packaging bag is limited, the distance between the two tabs of each battery cell is too small, and they are very likely to collide during production or transportation, resulting in a short circuit of the battery cell and affecting the safe use of the battery cell. Summary of the Utility Model

[0004] The main purpose of the utility model is to propose a lithium-ion battery, aiming to solve to a certain extent the technical problem that the two tabs of the existing battery cell are very likely to collide during production or transportation, resulting in a short circuit of the battery cell.

[0005] To achieve the above object, the utility model proposes a lithium-ion battery, including:

[0006] A housing, the housing is formed with an inner cavity;

[0007] An insulating partition, the insulating partition is arranged in the inner cavity to divide the inner cavity into a first insulating installation cavity and a second insulating installation cavity;

[0008] A first bare battery cell, the first bare battery cell includes a first battery cell body, a first tab and a second tab. The first battery cell body is accommodated in the first insulating installation cavity, and the first tab and the second tab are spaced and connected to the first battery cell body and extend out of the first insulating installation cavity from the first side of the housing. The first tab and the second tab have opposite polarities;

[0009] A second bare battery cell, the second bare battery cell includes a second battery cell body, a third tab and a fourth tab. The second battery cell body is accommodated in the second insulating installation cavity, and the third tab and the fourth tab are spaced and connected to the second battery cell body and extend out of the second insulating installation cavity from the first side. The third tab and the fourth tab have opposite polarities;

[0010] Wherein, in the length direction of the first side portion, one of the first tab and the second tab is located between the third tab and the fourth tab, and one of the third tab and the fourth tab is located between the first tab and the second tab.

[0011] In some embodiments, the arrangement order of the first tab, the second tab, the third tab and the fourth tab along the length direction of the first side portion is: the first tab, the third tab, the second tab, the fourth tab;

[0012] Wherein, one of the first tab and the second tab is the positive electrode and the other is the negative electrode;

[0013] One of the third tab and the fourth tab is the positive electrode and the other is the negative electrode.

[0014] In some embodiments, the outer shell is arranged in an L-shaped structure, the first bare battery cell and the second bare battery cell are respectively arranged in the L-shaped structure, and the first tab, the second tab, the third tab and the fourth tab are respectively exposed outside the short side of the L-shaped structure.

[0015] In some embodiments, the first bare battery cell, the insulating separator and the second bare battery cell are sequentially stacked in the thickness direction of the outer shell within the outer shell.

[0016] In some embodiments, the outer shell includes an upper shell and a lower shell, the upper shell and the lower shell are connected to enclose the inner cavity, and the upper shell and the upper surface of the insulating separator form the first insulating mounting cavity, and the lower shell and the lower surface of the insulating separator form the second insulating mounting cavity;

[0017] And / or, the outer shell is made of aluminum plastic film material.

[0018] In some embodiments, the insulating separator includes a metal layer, a first insulating encapsulation layer and a second insulating encapsulation layer, the first insulating encapsulation layer, the metal layer and the second insulating encapsulation layer are sequentially stacked, and the orthographic projection areas of the first insulating encapsulation layer and the second insulating encapsulation layer in the thickness direction of the outer shell are greater than or equal to the orthographic projection area of the metal layer in the thickness direction of the outer shell.

[0019] In some embodiments, the thickness of the insulating separator is greater than 0um and less than or equal to 100um.

[0020] In some embodiments, the lithium-ion battery further includes a circuit board located outside the outer shell, and the first tab, the second tab, the third tab and the fourth tab are respectively electrically connected to the circuit board to realize the series connection of the first bare battery cell and the second bare battery cell.

[0021] In some embodiments, the materials of the first insulating encapsulation layer and the second insulating encapsulation layer are one of polypropylene, polyethylene, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate, and ethylene-methacrylic acid.

[0022] In some embodiments, the material of the metal layer is one of nickel, aluminum, and iron.

[0023] The lithium-ion battery provided by this application extends the first tab, the second tab of the first bare battery cell, the third tab, and the fourth tab of the second bare battery cell to the first side of the housing. And in the length direction of the first side, one of the first tab and the second tab is located between the third tab and the fourth tab, and one of the third tab and the fourth tab is located between the first tab and the second tab. In this way, the distance between the first tab and the second tab, and between the third tab and the fourth tab can be increased as much as possible under the limitation of the battery cell size, avoiding the occurrence of short circuits in the battery cells caused by contact during production or transportation, thereby improving the safety of the battery cells. Description of the Drawings

[0024] Figure 1 It is a disassembled schematic diagram of an embodiment of the lithium-ion battery of the present utility model;

[0025] Figure 2 It is a structural schematic diagram of another embodiment of the lithium-ion battery of the present utility model;

[0026] Figure 3 It is a structural schematic diagram of another embodiment of the first bare battery cell of the present utility model;

[0027] Figure 4 It is a structural schematic diagram of another embodiment of the second bare battery cell of the present utility model;

[0028] Figure 5 It is a tab polarity schematic diagram of another embodiment of the lithium-ion battery of the present utility model.

[0029] Explanation of the reference numerals in the drawings:

[0030] Label Name Label Name 100 Lithium-ion battery 10 Outer shell 20 Insulating separator 30 First bare battery cell 31 First cell body 32 First tab 33 Second tab 40 Second bare battery cell 41 Second cell body 42 Third tab 43 Fourth tab 11 First side 12 Upper shell 13 Lower shell

[0031] The realization of the purpose, functional characteristics, and advantages of the present utility model will be further described in conjunction with the embodiments and with reference to the drawings. Detailed Embodiments

[0032] Next, the solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

[0033] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present utility model are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0034] It should also be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time.

[0035] In addition, the descriptions involving "first", "second", etc. in the present utility model are only for descriptive purposes and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present utility model.

[0036] Please refer to Figure 1 , the present utility model provides a lithium-ion battery 100, which includes a housing 10, an insulating partition 20, a first bare battery cell 30, and a second bare battery cell 40. The housing 10 forms an inner cavity; the insulating partition 20 is disposed in the inner cavity to divide the inner cavity into a first insulating installation cavity and a second insulating installation cavity; the first bare battery cell 30 includes a first battery cell body 31, a first tab 32, and a second tab 33. The first battery cell body 31 is accommodated in the first insulating installation cavity, and the first tab 32 and the second tab 33 are spaced and connected to the first battery cell body 31 and extend outside the first insulating installation cavity from the first side portion 11 of the housing 10. The polarities of the first tab 32 and the second tab 33 are opposite; the second bare battery cell 40 includes a second battery cell body 41, a third tab 42, and a fourth tab 43. The second battery cell body 41 is accommodated in the second insulating installation cavity, and the third tab 42 and the fourth tab 43 are spaced and connected to the second battery cell body 41 and extend outside the second insulating installation cavity from the first side portion 11. The polarities of the third tab 42 and the fourth tab 43 are opposite.

[0037] In this embodiment, the first battery cell body 31 is formed by laminating a first electrode sheet, a first separator, and a second electrode sheet in sequence. The first separator is disposed between the first electrode sheet and the second electrode sheet. The first tab 32 is connected to the first electrode sheet, and the second tab 33 is connected to the second electrode sheet. One of the first electrode sheet and the second electrode sheet is a positive electrode sheet, and the other is a negative electrode sheet.

[0038] Similarly, the second battery cell body 41 is formed by laminating a third electrode sheet, a second separator, and a fourth electrode sheet in sequence. The second separator is disposed between the third electrode sheet and the fourth electrode sheet. The third tab 42 is connected to the third electrode sheet, and the fourth tab 43 is connected to the fourth electrode sheet. One of the third electrode sheet and the fourth electrode sheet is a positive electrode sheet, and the other is a negative electrode sheet.

[0039] In some embodiments, the first bare battery cell 30, the insulating partition 20, and the second bare battery cell 40 are sequentially stacked in the thickness direction of the housing 10 and disposed within the housing 10. In this embodiment, by using the insulating partition 20, the inner cavity of the housing 10 is divided into a first insulating installation cavity and a second insulating installation cavity, and the first battery cell body 31 and the second battery cell body 41 are respectively encapsulated in the first insulating installation cavity and the second insulating installation cavity, thereby reducing the distance between the first battery cell body 31 and the second battery cell body 41, and further facilitating the reduction of the thickness of the entire lithium-ion battery 100 and improving the energy density of the lithium-ion battery 100.

[0040] Among them, in the length direction of the first side portion 11, one of the first tab 32 and the second tab 33 is located between the third tab 42 and the fourth tab 43, and one of the third tab 42 and the fourth tab 43 is located between the first tab 32 and the second tab 33. That is to say, the first tab 32 and the second tab 33 are arranged staggeredly, and the third tab 42 and the fourth tab 43 are arranged staggeredly. In this way, the distance between the first tab 32 and the second tab 33, and the third tab 42 and the fourth tab 43 can be increased as much as possible under the limitation of the size of the battery cell, avoiding the occurrence of short circuit of the battery cell caused by contact during production or transportation, thereby improving the safety of the battery cell.

[0041] In some embodiments, please refer to Figure 2 , the housing 10 is provided in an L-shaped structure. The first bare battery cell 30 and the second bare battery cell 40 are respectively disposed within the L-shaped structure, and the first tab 32, the second tab 33, the third tab 42, and the fourth tab 43 are respectively exposed outside the short side of the L-shaped structure.

[0042] In this embodiment, the L-shaped lithium-ion battery 100 can be correspondingly adapted according to the internal irregular structure of the application product. Since the short side width of the L-shape is smaller, the arrangement order of the first tab 32, the second tab 33, and the third tab 42 of the present application applied to the L-shaped lithium-ion battery 100 can solve the problem that the tabs of the existing L-shaped lithium-ion battery 100 are prone to contact and cause short circuits.

[0043] Of course, in other embodiments, the outer shell 10 can also be arranged in a rectangular structure or other common structures, and the present application does not make any limitations here.

[0044] In some embodiments, please refer to Figures 2 to 4 , the arrangement order of the first tab 32, the second tab 33, the third tab 42, and the fourth tab 43 along the length direction of the first side portion 11 is: the first tab 32, the third tab 42, the second tab 33, the fourth tab 43;

[0045] Among them, one of the first tab 32 and the second tab 33 is the positive electrode and the other is the negative electrode; one of the third tab 42 and the fourth tab 43 is the positive electrode and the other is the negative electrode. Correspondingly, the arrangement order of the first tab 32, the second tab 33, the third tab 42, and the fourth tab 43 along the length direction of the first side portion 11 can be one of the following: positive electrode, negative electrode, negative electrode, positive electrode; positive electrode, positive electrode, negative electrode, negative electrode; negative electrode, positive electrode, positive electrode, negative electrode; negative electrode, negative electrode, positive electrode, positive electrode. During actual production, it can be selected and set according to requirements.

[0046] Exemplarily, please refer to Figure 5 , in this embodiment, the arrangement order of the first tab 32, the second tab 33, the third tab 42, and the fourth tab 43 along the length direction of the first side portion 11 is positive electrode, positive electrode, negative electrode, negative electrode.

[0047] In some embodiments, the outer shell 10 includes an upper shell 12 and a lower shell 13. The upper shell 12 and the lower shell 13 are connected to enclose an inner cavity, and the upper shell 12 and the upper surface of the insulating partition 20 form a first insulating installation cavity, and the lower shell 13 and the lower surface of the insulating partition 20 form a second insulating installation cavity.

[0048] In this embodiment, the upper shell 12 and the lower shell 13 can protect the insulating partition 20 and prevent the insulating partition 20 from being damaged. In this way, the three-layer structure can play a better encapsulation role for the first battery cell body 31 and the second battery cell body 41, avoiding being affected by the outside.

[0049] Optionally, the upper shell 12, the lower shell 13, and the insulating partition 20 can be integrally formed, which can improve the structural strength. Of course, the upper shell 12, the lower shell 13, and the insulating partition 20 can also be adhesively bonded by hot melting or pasted by an adhesive.

[0050] In some embodiments, the outer shell 10 is made of aluminum-plastic film, that is, the lithium-ion battery 100 of the present application is a soft-pack lithium-ion battery 100. Of course, the outer shell 10 can also adopt the materials commonly used in the art, and the present application does not limit this here.

[0051] In some embodiments, the insulating separator 20 includes a metal layer, a first insulating encapsulation layer, and a second insulating encapsulation layer. The first insulating encapsulation layer, the metal layer, and the second insulating encapsulation layer are stacked in sequence. The metal layer provides strength support and plasticity for the first bare battery cell 30 and the second bare battery cell 40, and the orthographic projection areas of the first insulating encapsulation layer and the second insulating encapsulation layer in the thickness direction of the outer shell 10 are greater than or equal to the orthographic projection area of the metal layer in the thickness direction of the outer shell 10, ensuring that the first insulating encapsulation layer and the second insulating encapsulation layer cover the metal layer therein, so as to insulate and separate the first bare battery cell 30 from the second bare battery cell 40.

[0052] Preferably, the materials of the first insulating encapsulation layer and the second insulating encapsulation layer are one of polypropylene, polyethylene, ethylene-acrylic copolymer, ethylene-ethyl acrylate, and ethylene-methacrylic acid; the material of the metal layer is one of nickel, aluminum, and iron.

[0053] In some embodiments, the thickness of the insulating separator 20 is greater than 0 um and less than or equal to 100 um. For example, the thickness of the insulating separator 20 is 10 um, 25 um, 50 um, 75 um, 100 um, etc. In this embodiment, by controlling the thickness of the insulating separator 20, the insulation between the first bare battery cell 30 and the second bare battery cell 40 can be ensured, and the situation that the thickness of the insulating separator 20 is too large and affects the energy density of the lithium-ion battery 100 can be avoided.

[0054] In some embodiments, the lithium-ion battery 100 further includes a circuit board located outside the outer shell 10. The first tab 32, the second tab 33, the third tab 42, and the fourth tab 43 are respectively electrically connected to the circuit board to realize the series connection of the first bare battery cell 30 and the second bare battery cell 40, realize high-voltage output, reduce the temperature rise during charging and discharging, and moreover, there is no need to connect through wires and there is no redundant wire welding, improving the reliability and safety of the series connection of the first bare battery cell 30 and the second bare battery cell 40.

[0055] The following further elaborates the present utility model in combination with specific embodiments. It should be understood that these embodiments are only used to illustrate the present utility model and do not limit the scope of the present utility model.

[0056] Embodiment 1:

[0057] This embodiment provides a lithium-ion battery 100. The outer shell 10 is made of aluminum-plastic film material. The insulating separator 20 adopts a three-layer composite structure of polypropylene-aluminum, and the thickness of the insulating separator 20 is 100 um. The arrangement order of the tabs is: the first tab 32, the third tab 42, the second tab 33, and the fourth tab 43. Among them, the first tab 32 is the positive electrode, the second tab 33 is the negative electrode, the third tab 42 is the positive electrode, and the fourth tab 43 is the negative electrode.

[0058] Embodiment 2:

[0059] This embodiment provides a lithium-ion battery 100, which is different from Embodiment 1 in that: the first tab 32 is the negative electrode, the second tab 33 is the positive electrode, the third tab 42 is the negative electrode, and the fourth tab 43 is the positive electrode.

[0060] Comparative Example 1:

[0061] This comparative example provides a lithium-ion battery, which is different from Embodiment 1 in that: the arrangement order of the tabs is: the first tab, the second tab, the third tab, and the fourth tab, and the rest are the same.

[0062] Comparative Example 2:

[0063] This comparative example provides a lithium-ion battery, which is different from Embodiment 2 in that: the arrangement order of the tabs is: the first tab, the second tab, the third tab, and the fourth tab, and the rest are the same.

[0064] The lithium-ion batteries 100 of Embodiments 1-2 and Comparative Examples 1-2 are subjected to the formation process - K value test for the short-circuit defect rate of the battery cells. The test results are shown in Table 1:

[0065]

[0066] From the above test results, it can be concluded that the lithium-ion battery 100 of the present invention has good safety and can avoid the occurrence of short circuits of the battery cells caused by contact during production or transportation.

[0067] The above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation manners here. Any obvious changes or modifications derived from the technical solutions of the present invention still fall within the protection scope of the present invention.

Claims

1. A lithium-ion battery, characterized in that, Comprising: A housing, an inner cavity being formed in the housing; An insulating partition, the insulating partition being disposed within the inner cavity to divide the inner cavity into a first insulating mounting cavity and a second insulating mounting cavity; A first bare battery cell, the first bare battery cell including a first cell body, a first tab and a second tab, the first cell body being received within the first insulating mounting cavity, and the first tab and the second tab being spaced and connected to the first cell body and extending outside the first insulating mounting cavity from a first side portion of the housing, the first tab and the second tab having opposite polarities; A second bare battery cell, the second bare battery cell including a second cell body, a third tab and a fourth tab, the second cell body being received within the second insulating mounting cavity, and the third tab and the fourth tab being spaced and connected to the second cell body and extending outside the second insulating mounting cavity from the first side portion, the third tab and the fourth tab having opposite polarities; Wherein, in the length direction of the first side portion, one of the first tab and the second tab is located between the third tab and the fourth tab, and one of the third tab and the fourth tab is located between the first tab and the second tab.

2. The lithium-ion battery according to claim 1, characterized in that, The arrangement order of the first tab, the second tab, the third tab and the fourth tab along the length direction of the first side portion is: the first tab, the third tab, the second tab, the fourth tab; Wherein, one of the first tab and the second tab is a positive electrode and the other is a negative electrode; One of the third tab and the fourth tab is a positive electrode and the other is a negative electrode.

3. The lithium ion battery according to claim 1, wherein The housing is arranged in an L-shaped structure, the first bare battery cell and the second bare battery cell are respectively arranged within the L-shaped structure, and the first tab, the second tab, the third tab and the fourth tab respectively protrude outside the short side of the L-shaped structure.

4. The lithium-ion battery according to claim 1, characterized in that, The first bare battery cell, the insulating partition and the second bare battery cell are sequentially stacked in the thickness direction of the housing within the housing.

5. The lithium-ion battery according to any one of claims 1 to 4, characterized in that, The housing includes an upper shell and a lower shell, the upper shell and the lower shell are connected to enclose the inner cavity, and the upper shell and the upper surface of the insulating partition form the first insulating mounting cavity, and the lower shell and the lower surface of the insulating partition form the second insulating mounting cavity; And / or, the housing is made of an aluminum plastic film material.

6. The lithium ion battery according to any one of claims 1 to 4, characterized in that, The insulating partition includes a metal layer, a first insulating encapsulation layer and a second insulating encapsulation layer, the first insulating encapsulation layer, the metal layer and the second insulating encapsulation layer are sequentially stacked, and the orthographic projection areas of the first insulating encapsulation layer and the second insulating encapsulation layer in the thickness direction of the housing are greater than or equal to the orthographic projection area of the metal layer in the thickness direction of the housing.

7. The lithium-ion battery according to any one of claims 1 to 4, characterized in that, The thickness of the insulating partition is greater than 0um and less than or equal to 100um.

8. The lithium ion battery according to any one of claims 1 to 4, characterized in that, The lithium ion battery further includes a circuit board located outside the housing, and the first tab, the second tab, the third tab and the fourth tab are respectively electrically connected to the circuit board to realize the series connection of the first bare battery cell and the second bare battery cell.

9. The lithium-ion battery according to claim 6, wherein, The material of the first insulating encapsulation layer and the second insulating encapsulation layer is one of polypropylene, polyethylene, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate, and ethylene-methacrylic acid.

10. The lithium-ion battery according to claim 6, characterized in that, The material of the metal layer is one of nickel, aluminum, and iron.

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