A single cell and a battery pack

Abstract

The application discloses a single battery and a battery pack, and belongs to the technical field of batteries. The single battery comprises a shell, a current collection top cover and an electrode assembly. The shell has an accommodating cavity with an open end; the current collection top cover is sealed to the opening; and the electrode assembly is arranged in the accommodating cavity. The electrode assembly comprises a roll core body, a negative full tab and a positive full tab. The negative full tab is connected to one end of the roll core body away from the opening and is electrically connected to the shell. The positive full tab is connected to one end of the roll core body close to the opening and is electrically connected to the current collection top cover. The single battery provided by the application reduces the overall weight and overall internal resistance of the single battery, improves the energy density of the single battery, and reduces energy loss such as heat generation of the single battery in the charging and discharging process.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a single cell battery and a battery pack. Background Technology

[0002] Driven by the "dual carbon" policy, the new energy industry has developed rapidly. Lithium-ion batteries and sodium-ion batteries, as important rechargeable batteries, have been widely used in digital products, electric vehicle power systems and energy storage due to their advantages such as high energy density, compact structure, fast charging and discharging speed, low self-discharge rate and long cycle life.

[0003] Based on the different tab structures, lithium-ion and sodium-ion batteries can be divided into single-tab, multi-tab, and full-tab structures. Full-tab batteries further include same-side full-tab and vertical full-tab types. Vertical full-tab batteries are characterized by low internal resistance and high safety. The positive current of the positive tab is typically conducted to the top cover through the positive current collector, while the negative current of the negative tab is conducted to the casing through the negative current collector. However, the presence of the current collector not only increases the overall weight of the battery, leading to a decrease in energy density, but also increases the overall internal resistance, resulting in increased energy loss such as heat generation during charging and discharging. Summary of the Invention

[0004] In view of this, the purpose of this application is to overcome the shortcomings of the prior art and provide a single cell battery.

[0005] To solve the above-mentioned technical problems, this application provides: A single-cell battery, comprising: The housing has a receiving cavity open at one end; A top cover for collecting current, which seals the opening; An electrode assembly is disposed within the receiving cavity. The electrode assembly includes a core body, a negative electrode tab, and a positive electrode tab. The negative electrode tab is connected to the end of the core body away from the opening and is electrically connected to the housing. The positive electrode tab is connected to the end of the core body near the opening and is electrically connected to the current collector top cover.

[0006] In addition, the single cell according to this application may also have the following additional technical features: In some embodiments of this application, the current collector top cover includes a current collector portion and a pole portion, the current collector portion being electrically connected to the positive electrode tab, and the pole portion being connected to the side of the current collector portion away from the positive electrode tab.

[0007] In some embodiments of this application, the single cell further includes a negative electrode lead and an insulating seal, wherein the negative electrode lead is electrically connected to the inner circumferential wall of the end of the housing having the opening, and the insulating seal abuts between the circumferential wall of the current collector and the inner circumferential wall of the negative electrode lead.

[0008] In some embodiments of this application, the negative electrode lead-out member has a negative electrode lead-out portion on the side away from the electrode assembly.

[0009] In some embodiments of this application, the inner circumferential wall of the negative electrode lead-out member is provided with a first annular groove, the circumferential wall of the current collector is provided with a first annular protrusion, the first annular protrusion is located in the first annular groove, and the insulating seal abuts between the first annular protrusion and the groove wall of the first annular groove.

[0010] In some embodiments of this application, the inner circumferential wall of the insulating seal is provided with a second annular groove, and the first annular protrusion is disposed in the second annular groove.

[0011] In some embodiments of this application, the inner circumferential wall of the end of the housing with the opening is provided with a second annular protrusion, and the negative electrode lead is disposed on the side of the second annular protrusion away from the electrode assembly and is electrically connected to the second annular protrusion.

[0012] In some embodiments of this application, the single cell further includes a first insulating member, which includes a first insulating portion and a second insulating portion connected together. The first insulating portion is disposed between the circumferential wall of the positive electrode tab and the inner circumferential wall of the housing, and the second insulating portion is disposed between the positive electrode tab and the second annular protrusion.

[0013] In some embodiments of this application, the single cell further includes a second insulating member disposed between the current collector and the negative electrode lead-out portion, and located between the circumferential wall of the electrode post portion and the inner circumferential wall of the negative electrode lead-out portion.

[0014] Secondly, this application also provides a battery pack, including the single battery cells described in any of the above embodiments.

[0015] Compared to existing technologies, the beneficial effects of this application are: This application proposes a single-cell battery, comprising a casing, a current collector top cover, and an electrode assembly. The casing has a receiving cavity with an opening at one end, and the current collector top cover seals the opening. The electrode assembly is disposed within the receiving cavity and includes a core body, a negative electrode tab, and a positive electrode tab. The negative electrode tab is connected to the end of the core body away from the opening, and the positive electrode tab is connected to the end of the core body closer to the opening. By electrically connecting the negative electrode tab to the casing, the flow path of the negative electrode current is made through the negative electrode tab and the casing. Similarly, by electrically connecting the positive electrode tab to the current collector top cover, the flow path of the positive electrode current is made through the positive electrode tab and the current collector top cover. This eliminates the need for the negative and positive current collectors in the prior art, thereby reducing the overall weight and internal resistance of the single-cell battery, thus increasing its energy density and reducing energy losses such as heat generation during charging and discharging. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A perspective view of a single cell in some embodiments of this application is shown; Figure 2 An exploded view of a single cell in some embodiments of this application is shown; Figure 3 The diagram shows a cross-sectional view of a single cell in some embodiments of this application; Figure 4 It shows Figure 3 Enlarged schematic diagram of the structure of section A in the middle.

[0018] Explanation of key component symbols: 100-cell battery; 110 - Shell; 111 - Opening; 112 - Receiving cavity; 113 - Second annular protrusion; 120 - Current collector top cover; 121 - Current collector section; 1211 - First annular protrusion; 122 - Pole post section; 130 - Electrode assembly; 131 - Core body; 132 - Negative electrode tab; 133 - Positive electrode tab; 140 - Negative electrode lead-out component; 141 - Negative electrode lead-out portion; 142 - First annular groove; 150 - Insulating seal; 151 - Second annular groove; 160 - First insulating element; 161 - First insulating part; 162 - Second insulating part; 170 - Second insulating element. Detailed Implementation

[0019] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0020] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0022] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0023] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0024] like Figure 1 and Figure 2 As shown, an embodiment of this application provides a single-cell battery 100, mainly used in battery packs. The single-cell battery 100 includes a housing 110, a current collector top cover 120, and an electrode assembly 130.

[0025] See also Figure 3 and Figure 4 The housing 110 has a receiving cavity 112 with an opening 111 at one end, and the current collector top cover 120 seals the opening 111. The electrode assembly 130 is disposed in the receiving cavity 112. The electrode assembly 130 includes a core body 131, a negative electrode tab 132, and a positive electrode tab 133. The negative electrode tab 132 is connected to the end of the core body 131 away from the opening 111 and is electrically connected to the housing 110. The positive electrode tab 133 is connected to the end of the core body 131 near the opening 111 and is electrically connected to the current collector top cover 120.

[0026] The embodiments of this application provide a single-cell battery 100, which includes a housing 110, a current collector top cover 120, and an electrode assembly 130. The housing 110 has a receiving cavity 112 with an opening 111 at one end. The current collector top cover 120 is sealed to the opening 111. The electrode assembly 130 is disposed in the receiving cavity 112. The electrode assembly 130 includes a core body 131, a negative electrode tab 132, and a positive electrode tab 133. The negative electrode tab 132 is connected to the end of the core body 131 away from the opening 111, and the positive electrode tab 133 is connected to the end of the core body 131 near the opening 111. By electrically connecting the negative electrode tab 132 to the housing 110, the flow path of the negative electrode current is through the negative electrode tab 132 and the housing 110. By electrically connecting the positive electrode tab 133 to the current collector top cover 120, the flow path of the positive electrode current is through the positive electrode tab 133 and the current collector top cover 120. This eliminates the negative electrode current collector and positive electrode current collector in the prior art, thereby reducing the overall weight and internal resistance of the single cell 100, thus improving the energy density of the single cell 100 and reducing energy loss such as heat generation during the charging and discharging process.

[0027] For example, the negative electrode tab 132 and the housing 110 can be electrically connected by laser welding, and the positive electrode tab 133 and the current collector top cover 120 can be electrically connected by laser welding.

[0028] like Figure 1 , Figure 2 and Figure 4 As shown, in one embodiment of this application, the current collector top cover 120 includes a current collector 121 and a pole post 122. The current collector 121 is electrically connected to the positive electrode tab 133, and the pole post 122 is connected to the side of the current collector 121 away from the positive electrode tab 133.

[0029] In this embodiment, the current collector 121 is electrically connected to the positive electrode tab 133. By providing a terminal post 122 connected to the current collector 121 on the side of the current collector 121 away from the positive electrode tab 133, the flow path of the positive electrode current is the positive electrode tab 133, the current collector 121 and the terminal post 122, so that the positive electrode current is led out through the terminal post 122, thereby realizing the charging and discharging of the single cell battery 100.

[0030] For example, the pole portion 122 and the current collector portion 121 can be formed by stamping or machining.

[0031] like Figure 1 , Figure 2 and Figure 4 As shown in the above embodiments of this application, the single cell 100 further includes a negative electrode lead-out member 140 and an insulating seal member 150. The negative electrode lead-out member 140 is electrically connected to the inner circumferential wall of the end of the housing 110 having the opening 111, and the insulating seal member 150 abuts between the circumferential wall of the current collector 121 and the inner circumferential wall of the negative electrode lead-out member 140.

[0032] In this embodiment, by providing a negative electrode lead-out member 140 electrically connected to the inner circumferential wall of the end of the housing 110 with an opening 111, the flow path of the negative electrode current is the negative electrode tab 132, the housing 110 and the negative electrode lead-out member 140, thereby leading out the negative electrode current through the negative electrode lead-out member 140 to realize the charging and discharging of the single cell battery 100.

[0033] By abutting the insulating seal 150 between the circumferential wall of the current collector 121 and the inner circumferential wall of the negative lead 140, the electrical gap between the circumferential wall of the current collector 121 and the inner circumferential wall of the negative lead 140 can be isolated by the insulating effect of the insulating seal 150, so as to avoid the technical problem of short circuit caused by the current collector 121 carrying positive current coming into contact with the negative lead 140 carrying negative current.

[0034] On the other hand, the gap between the circumferential wall of the current collector 121 and the inner circumferential wall of the negative electrode lead-out member 140 can be sealed by the sealing action of the insulating seal 150, thereby preventing the electrolyte in the receiving cavity 112 from leaking to the outside of the housing 110 through the gap between the circumferential wall of the current collector 121 and the inner circumferential wall of the negative electrode lead-out member 140.

[0035] For example, the negative lead 140 and the inner circumferential wall of the housing 110 can be electrically connected by laser welding, and the insulating seal 150 can be made of rubber or silicone.

[0036] like Figure 1 , Figure 2 and Figure 4 As shown, in the above embodiments of this application, the negative electrode lead-out member 140 is provided with a negative electrode lead-out portion 141 on the side away from the electrode assembly 130.

[0037] In this embodiment, by providing a negative electrode lead-out portion 141 on the side of the negative electrode lead-out member 140 away from the electrode assembly 130, the flow path of the negative electrode current is the negative electrode tab 132, the housing 110, the negative electrode lead-out member 140 and the negative electrode lead-out portion 141, thereby leading out the negative electrode current through the negative electrode lead-out portion 141 to realize the charging and discharging of the single cell battery 100.

[0038] This configuration ensures that both the positive and negative currents originate from the end of the housing 110 with the opening 111. This facilitates placing the explosion-proof valve at the end of the housing 110 furthest from the opening 111, achieving thermoelectric separation and effectively improving safety. Furthermore, having both the positive and negative currents originate from the end of the housing 110 with the opening 111 simplifies the structure and steps for connecting multiple individual cells 100 in series or parallel within the battery pack.

[0039] For example, the negative electrode lead-out portion 141 and the negative electrode lead-out member 140 can be made by stamping or machining.

[0040] like Figure 2 and Figure 4 As shown in the above embodiments of this application, the inner circumferential wall of the negative electrode lead-out member 140 is provided with a first annular groove 142, the circumferential wall of the current collecting part 121 is provided with a first annular protrusion 1211, the first annular protrusion 1211 is located in the first annular groove 142, and the insulating seal member 150 abuts between the first annular protrusion 1211 and the groove wall of the first annular groove 142.

[0041] In this embodiment, by creating a first annular groove 142 in the inner circumferential wall of the negative electrode lead-out member 140, and providing a first annular protrusion 1211 located in the first annular groove 142 in the circumferential wall of the current collector 121, and abutting the insulating seal 150 between the first annular protrusion 1211 and the groove wall of the first annular groove 142, the insulation and sealing effects of the insulating seal 150 can be improved, and the probability of short circuit caused by contact between the current collector 121 and the negative electrode lead-out member 140 and electrolyte leakage through the gap between the circumferential wall of the current collector 121 and the inner circumferential wall of the negative electrode lead-out member 140 can be further reduced.

[0042] On the other hand, the first annular groove 142 can be used to limit the insulating seal 150 and the first annular protrusion 1211 to limit the current collector top cover 120, thereby preventing the current collector 121 from separating from the positive electrode tab 133 and ensuring the stability and reliability of the electrical connection between the current collector 121 and the positive electrode tab 133.

[0043] like Figure 2 and Figure 4 As shown in the above embodiments of this application, the inner circumferential wall of the insulating seal 150 is provided with a second annular groove 151, and the first annular protrusion 1211 is disposed in the second annular groove 151.

[0044] In this embodiment, by creating a second annular groove 151 in the inner circumferential wall of the insulating seal 150 and placing a first annular protrusion 1211 inside the second annular groove 151, the contact area between the insulating seal 150 and the groove wall of the first annular protrusion 1211 and the first annular groove 142 is effectively increased, thereby further improving the insulation and sealing effect of the insulating seal 150. This further reduces the probability of short circuit caused by contact between the current collector 121 and the negative electrode lead 140, as well as the leakage of electrolyte through the gap between the circumferential wall of the current collector 121 and the inner circumferential wall of the negative electrode lead 140.

[0045] On the other hand, the limiting effect of the current collector top cover 120 can be improved by using the first annular groove 142 to limit the insulating seal 150 and the second annular groove 151 to limit the first annular protrusion 1211, thereby further reducing the probability of the current collector 121 separating from the positive electrode tab 133 and further ensuring the stability and reliability of the electrical connection between the current collector 121 and the positive electrode tab 133.

[0046] like Figure 2 and Figure 4As shown in the above embodiments of this application, the inner circumferential wall of the housing 110 having the opening 111 is provided with a second annular protrusion 113, and the negative electrode lead-out member 140 is disposed on the side of the second annular protrusion 113 away from the electrode assembly 130 and is electrically connected to the second annular protrusion 113.

[0047] In this embodiment, a second annular protrusion 113 is provided on the inner circumferential wall of the end of the housing 110 with an opening 111. The negative electrode lead 140 is located on the side of the second annular protrusion 113 away from the electrode assembly 130 and is electrically connected to the second annular protrusion 113. This can improve the stability and reliability of the electrical connection between the negative electrode lead 140 and the housing 110 by utilizing the supporting effect of the second annular protrusion 113 on the negative electrode lead 140. Furthermore, the supporting effect of the second annular protrusion 113 on the negative electrode lead 140 can be used to support the negative electrode lead 140, the insulating seal 150 and the current collector top cover 120 as a whole, so as to avoid the electrode assembly 130 being crushed by the gravity of the negative electrode lead 140, the insulating seal 150 and the current collector top cover 120 as a whole.

[0048] On the other hand, the electrical connection between the negative lead 140 and the second annular protrusion 113 can also increase the contact area between the negative lead 140 and the housing 110, thereby further improving the stability and reliability of the electrical connection between the negative lead 140 and the housing 110.

[0049] For example, the negative lead 140 and the second annular protrusion 113 can be electrically connected by laser welding.

[0050] like Figure 2 As shown in the above embodiments of this application, the single cell battery 100 further includes a first insulating member 160. The first insulating member 160 includes a first insulating portion 161 and a second insulating portion 162 connected together. The first insulating portion 161 is disposed between the circumferential wall of the positive electrode tab 133 and the inner circumferential wall of the housing 110. The second insulating portion 162 is disposed between the positive electrode tab 133 and the second annular protrusion 113.

[0051] In this embodiment, by disposing the first insulating part 161 between the circumferential wall of the positive electrode tab 133 and the inner circumferential wall of the housing 110, the electrical gap between the circumferential wall of the positive electrode tab 133 and the inner circumferential wall of the housing 110 is isolated by the insulating effect of the first insulating part 161, thereby avoiding the technical problem of short circuit caused by the positive electrode tab 133 carrying positive current contacting the housing 110 carrying negative current.

[0052] Meanwhile, by placing the second insulating part 162 between the positive electrode tab 133 and the second annular protrusion 113, the electrical gap between the positive electrode tab 133 and the second annular protrusion 113 is isolated by the insulating effect of the second insulating part 162, thereby avoiding the technical problem of short circuit caused by the positive electrode tab 133 carrying positive current contacting the second annular protrusion 113 carrying negative current.

[0053] For example, the first insulating element 160 may be high-temperature resistant insulating tape.

[0054] like Figure 1 , Figure 2 and Figure 4 As shown in the above embodiments of this application, the single cell 100 further includes a second insulating member 170, which is disposed between the current collecting portion 121 and the negative electrode lead-out portion 141, and is located between the circumferential wall of the electrode post portion 122 and the inner circumferential wall of the negative electrode lead-out portion 140.

[0055] In this embodiment, a second insulating member 170 is provided between the current collector 121 and the negative lead-out portion 141 between the circumferential wall of the pole post 122 and the inner circumferential wall of the negative lead-out portion 140. The electrical gap between the current collector 121 and the negative lead-out portion 141 is isolated by the insulating effect of the second insulating member 170, thereby avoiding the technical problem of short circuit caused by the negative lead-out portion 141 carrying negative current collapsing and deforming and coming into contact with the current collector 121 carrying positive current.

[0056] For example, the material of the second insulating element 170 may be a polymer plastic.

[0057] This application also provides a battery pack, including the single battery cell 100 described in the above embodiments.

[0058] The battery pack has the single cell 100 of any of the above embodiments, and therefore has all the beneficial effects of the single cell 100, which will not be described in detail here.

[0059] The battery pack has a housing and at least one individual battery cell 100 as described in any of the above embodiments, the individual battery cell 100 being disposed within the housing. When there are multiple individual batteries cell 100, the multiple individual batteries cell 100 can be connected in series or in parallel, or in a combination of series and parallel connections.

[0060] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0061] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A single-cell battery, characterized in that, include: The housing (110) has a receiving cavity (112) with an opening (111) at one end. A top cover (120) is used to seal the opening (111). An electrode assembly (130) is disposed within the receiving cavity (112). The electrode assembly (130) includes a core body (131), a negative electrode tab (132), and a positive electrode tab (133). The negative electrode tab (132) is connected to the end of the core body (131) away from the opening (111) and is electrically connected to the housing (110). The positive electrode tab (133) is connected to the end of the core body (131) near the opening (111) and is electrically connected to the current collector top cover (120).

2. The single-cell battery according to claim 1, characterized in that, The current collector top cover (120) includes a current collector (121) and a pole piece (122). The current collector (121) is electrically connected to the positive electrode tab (133), and the pole piece (122) is connected to the side of the current collector (121) away from the positive electrode tab (133).

3. The single-cell battery according to claim 2, characterized in that, The single cell (100) further includes a negative electrode lead-out member (140) and an insulating seal member (150). The negative electrode lead-out member (140) is electrically connected to the inner circumferential wall of the end of the housing (110) having the opening (111). The insulating seal member (150) abuts against the circumferential wall of the current collector (121) and the inner circumferential wall of the negative electrode lead-out member (140).

4. The single-cell battery according to claim 3, characterized in that, The negative electrode lead-out member (140) has a negative electrode lead-out portion (141) on the side away from the electrode assembly (130).

5. The single-cell battery according to claim 3, characterized in that, The negative electrode lead-out member (140) has a first annular groove (142) on its inner circumferential wall, and the current collector (121) has a first annular protrusion (1211) on its circumferential wall. The first annular protrusion (1211) is located in the first annular groove (142), and the insulating seal (150) abuts between the first annular protrusion (1211) and the groove wall of the first annular groove (142).

6. The single-cell battery according to claim 5, characterized in that, The inner circumferential wall of the insulating seal (150) is provided with a second annular groove (151), and the first annular protrusion (1211) is disposed in the second annular groove (151).

7. The single-cell battery according to claim 3, characterized in that, The housing (110) has a second annular protrusion (113) on the inner circumferential wall of one end of the opening (111). The negative electrode lead-out member (140) is disposed on the side of the second annular protrusion (113) away from the electrode assembly (130) and is electrically connected to the second annular protrusion (113).

8. The single-cell battery according to claim 7, characterized in that, The single cell (100) further includes a first insulating member (160), the first insulating member (160) includes a first insulating part (161) and a second insulating part (162) connected together, the first insulating part (161) is disposed between the circumferential wall of the positive electrode tab (133) and the inner circumferential wall of the housing (110), and the second insulating part (162) is disposed between the positive electrode tab (133) and the second annular protrusion (113).

9. The single-cell battery according to claim 4, characterized in that, The single cell (100) further includes a second insulating member (170), which is disposed between the current collector (121) and the negative electrode lead-out portion (141), and is located between the circumferential wall of the electrode post portion (122) and the inner circumferential wall of the negative electrode lead-out portion (140).

10. A battery pack, characterized in that, Includes the single cell (100) according to any one of claims 1 to 9.

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