Battery and battery pack

Abstract

The utility model provides a battery and a battery pack. The battery comprises a shell, a cover plate assembly and an electrode assembly, wherein an electrode main body is provided with a tab; the tab is connected with the adapter plate in a welding manner to form a first welding mark, the orthographic projection of the first welding mark on the cover plate assembly is located in a first area, and the first area is located at one end, far away from the axis side of the battery, of the cover plate assembly; the adapter sheet and the pole are welded and connected to form a second welding mark, the orthographic projection of the second welding mark on the cover plate assembly is located in the second area, and the first area is located between the second area and the axis side of the battery. The battery further comprises a first protection piece and a second protection piece, the first protection piece covers the first welding mark, and the second protection piece covers the second welding mark and at least partially covers the first protection piece, so that the support of the second protection piece is added on the basis that the first protection piece supports the tab, and the tab is more stable; the problems that the tab is loosened and is in contact with a pole piece in the battery to cause short circuit are greatly reduced, and the safety of the battery is improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery and a battery pack. Background Art

[0002] As lithium-ion battery technology becomes increasingly mature, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage fields, and the requirements for the performance and safety of lithium-ion batteries are also increasing.

[0003] A battery may include a cover plate assembly and an electrode assembly. The electrode body comprising the electrode assembly has tabs, which are welded to the cover plate assembly via adapters. The electrode assembly is formed by bending the tabs. However, as the battery's service life increases, the bent tabs tend to loosen, reducing their stability and allowing them to contact the electrode sheets in the electrode assembly, causing a short circuit and potentially leading to battery safety issues. Utility Model Content

[0004] In view of this, the purpose of this application is to provide a battery and a battery pack to solve or partially solve the above problems.

[0005] Based on the above objectives, in a first aspect, the present application provides a battery, comprising:

[0006] a housing, wherein a first surface of the housing is open;

[0007] a cover plate assembly covering the first surface, the cover plate assembly comprising a cover plate body and a pole insulated from the cover plate body;

[0008] An electrode assembly is disposed in the housing, wherein the electrode assembly includes one or more electrode bodies, each of which has a tab;

[0009] An adapter plate, the adapter plate being arranged between the tab and the cover plate assembly;

[0010] The tab is welded to the adapter to form a first weld mark, the orthographic projection of the first weld mark on the cover plate assembly is located in a first area, and the first area is located at an end of the cover plate assembly away from the battery axis;

[0011] The adapter is welded to the terminal to form a second weld mark, the orthographic projection of the second weld mark on the cover assembly is located in the second area, and the first area is located between the second area and the battery axis side;

[0012] The battery further includes a first protective member and a second protective member, wherein the first protective member covers the first weld mark, and the second protective member covers the second weld mark and at least partially covers the first protective member.

[0013] In a second aspect of the present application, a battery pack is provided, comprising the battery as described in the first aspect.

[0014] As can be seen from the above, the present application provides a battery and battery pack. The battery includes: a shell, a cover assembly, an electrode assembly, the electrode body having a tab; an adapter plate, wherein the tab is welded to the adapter plate to form a first weld mark, the orthographic projection of the first weld mark on the cover assembly is located in a first region, and the first region is located at the end of the cover assembly away from the battery axis; the adapter plate is welded to the pole column to form a second weld mark, the orthographic projection of the second weld mark on the cover assembly is located in a second region, and the first region is located between the second region and the battery axis. The battery also includes a first protective member and a second protective member, with the first protective member covering the first weld mark, and the second protective member covering the second weld mark and at least partially covering the first protective member. This provides additional support for the tab by the second protective member in addition to the support provided by the first protective member, making the tab more stable, greatly reducing the problem of the tab becoming loose and short-circuiting due to contact with the pole piece in the battery, and improving the safety of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in this application or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are merely embodiments of this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0016] Figure 1 A schematic diagram of an exemplary battery according to an embodiment of the present application is shown.

[0017] Figure 2A A schematic structural diagram of an exemplary electrode assembly according to an embodiment of the present application is shown.

[0018] Figure 2B A schematic structural diagram of another exemplary electrode assembly according to an embodiment of the present application is shown.

[0019] Figure 3A A bottom-view structural schematic diagram of an exemplary electrode assembly according to an embodiment of the present application is shown.

[0020] Figure 3B A schematic oblique structural diagram of an exemplary electrode assembly according to an embodiment of the present application is shown.

[0021] Figure 4 A schematic oblique structural diagram of another exemplary electrode assembly according to an embodiment of the present application is shown.

[0022] Figure 5A schematic oblique structural diagram of another exemplary electrode assembly according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0023] In order to make the objectives, technical solutions and advantages of this application more clear, this application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0024] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should have the usual meanings understood by people with ordinary skills in the field to which this application belongs. The "first", "second" and similar words used in the embodiments of the present application do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0025] As described above, a battery may include a cover plate assembly and an electrode assembly. The electrode body comprising the electrode assembly includes a tab, which is welded to the cover plate assembly via an adapter. The electrode assembly is formed by bending the tab. However, as the battery's service life increases, the bent tabs tend to loosen, resulting in reduced stability and contact with the electrode sheets in the electrode assembly, causing a short circuit and potentially leading to battery safety issues.

[0026] Inserting the tab into the electrode sheet will cause an internal short circuit in the electrode assembly, leading to increased self-discharge of the electrode assembly. In severe cases, it may also cause safety problems such as fire and explosion of the electrode assembly.

[0027] To at least address the aforementioned issues, the present application provides a battery and battery pack. The battery comprises: a housing, a cover assembly, an electrode assembly, the electrode body having a tab; an adapter plate, wherein the tab is welded to the adapter plate to form a first weld mark, the orthographic projection of the first weld mark on the cover assembly being located in a first region, the first region being located at the end of the cover assembly away from the battery axis; and the adapter plate is welded to the electrode post to form a second weld mark, the orthographic projection of the second weld mark on the cover assembly being located in a second region, the first region being located between the second region and the battery axis. The battery further comprises a first protective member and a second protective member, wherein the first protective member covers the first weld mark, and the second protective member covers the second weld mark and at least partially covers the first protective member. This provides additional support for the tab by the second protective member in addition to the support provided by the first protective member, making the tab more stable, significantly reducing the problem of the tab becoming loose and causing a short circuit in contact with the electrode in the battery, and improving the safety of the battery.

[0028] Figure 1 A schematic diagram of an exemplary battery 100 according to an embodiment of the present application is shown.

[0029] like Figure 1 As shown, the battery 100 may include a shell 102 and a cover assembly 104, the shell 102 having a first surface 106 (e.g., top surface) and a second surface (e.g., bottom surface) arranged opposite to each other, two third surfaces 108 (e.g., front surface) and two fourth surfaces 112 (e.g., side surfaces) arranged opposite to each other. The first surface 106 is open, and the cover assembly 104 covers the first surface 106. The cover assembly 104 may include a cover body and a pole 110 insulated from the cover body, and the pole 110 may be divided into a positive pole and a negative pole. The pole 110 may be arranged to protrude relative to the cover body. The battery cell 100 may also include an electrode assembly 200 arranged in the shell 102.

[0030] Figure 2A A schematic structural diagram of an exemplary electrode assembly 200 according to an embodiment of the present application is shown.

[0031] like Figure 2A As shown, the electrode assembly 200 may include one or more electrode bodies 202, each having a tab 206. The battery 100 may further include a transfer sheet 204, which is disposed between the tab 206 and the cap assembly 104. The tab 206 may be welded to the transfer sheet 204 to form a first weld mark 208 (e.g., an ultrasonic weld mark). The orthographic projection of the first weld mark 208 on the cap assembly 104 is located in a first region, which is located at one end of the cap assembly 104 away from the battery axis 210.

[0032] Figure 2B FIG2 shows a schematic structural diagram of another exemplary electrode assembly 200 according to an embodiment of the present application.

[0033] Combine Figure 2A and Figure 2B It can be understood that before forming the electrode assembly 200 , one or more electrode bodies 202 are located on both sides of the tabs 206 , and the electrode assembly 200 is formed by bending the tabs 206 along the direction X toward the battery axis 210 .

[0034] The adapter plate 204 can be welded to the terminal post 110 to form a second weld mark (e.g., a laser weld mark). The orthographic projection of the second weld mark on the cover plate assembly 104 is located in the second area, and the first area is located between the second area and the battery axial side 210. In this way, the positions of the first and second weld marks are staggered, which can effectively reduce the thickness of the battery. In some embodiments, the thickness of the battery 100 can be less than or equal to 50 mm.

[0035] When the electrode assembly 200 includes a single electrode body, in some embodiments, the battery 100 may include a first protective member that covers the first weld mark 208. This first protective member prevents weld mark residue from entering the battery cell or preventing overlap between the positive and negative electrodes, which could cause a short circuit. Furthermore, the first protective member also provides support for the tabs 206, preventing redundant tabs 206 from being inserted into the electrode sheet of the electrode body 202, potentially causing tab insertion.

[0036] In some embodiments, the battery 100 may further include a second protective member, which may cover the second weld mark to prevent weld mark residue from falling into the battery cell.

[0037] To further strengthen the first protective member's support for the tab 206, in some embodiments, a second protective member can cover the second weld mark and at least partially cover the first protective member. The first and second protective members can be adhesive tape. This partial coverage of the second protective member overlies the first protective member, providing an additional layer of support, while the first protective member alone supports the tab 206. This further stabilizes the tab 206 and significantly reduces the risk of a pole piece being inserted into the tab 206.

[0038] In order to further enhance the stability of the protection member supporting the tab 206, in some embodiments, the thickness of the second protection member can be greater than or equal to the thickness of the first protection member. In this way, the thicker the protection member supporting the tab 206, the more stable the tab 206 will be.

[0039] Figure 3A A bottom-view structural schematic diagram of an exemplary electrode assembly 200 according to an embodiment of the present application is shown. Figure 3B A schematic oblique structural diagram of an exemplary electrode assembly 200 according to an embodiment of the present application is shown.

[0040] Combine Figure 3A and Figure 3B When the electrode assembly 200 includes multiple electrode bodies, in some embodiments, the electrode assembly 200 may include a first electrode body 402 and a second electrode body 404. The first electrode body 402 has a first tab, and the second electrode body 404 has a second tab. The first electrode body 402 and the second electrode body 404 are arranged side by side, with the first tab and the second tab located on the same side of the electrode assembly 200. The first weld mark 208 may include a first sub-weld mark 406 and a second sub-weld mark 408. The first tab may be welded to the adapter sheet 204 to form the first sub-weld mark 406, and the second tab may be welded to the adapter sheet 204 to form the second sub-weld mark 408. The first protective member 42 may include a first portion 410 and a second portion 412. The first portion 410 may cover the first sub-weld mark 406, and the second portion 412 may cover the second sub-weld mark 408. In this way, the first portion 410 and the second portion 412 can prevent weld mark residue from falling into the battery cell while providing support for the first and second tabs.

[0041] In some embodiments, the second protective member 414 can cover the second weld mark 302 to prevent weld residue from falling into the battery cell. For electrode assemblies 200 having multiple electrode bodies, in some embodiments, the second protective member 414 can cover the second weld mark 302 and at least partially cover the first portion 410 and the second portion 412. This provides additional support for the first and second tabs, while only one layer of the first and second portions 410, 412 supports them. This provides additional support for the first and second tabs, further stabilizing them and significantly reducing the risk of a pole piece being inserted into them.

[0042] In some embodiments, the area of ​​the first protective member 42 is greater than or equal to the area of ​​the first weld mark 208, and the area of ​​the second protective member 414 is greater than or equal to the area of ​​the second weld mark 302. This ensures that the protective member can completely cover the weld mark.

[0043] The length of the overlap between the second and first protective members can be determined experimentally. For example, experimental groups 1 to 5 can be set up. In experimental group 1, the overlap between the second and first protective members is 70% of the length of the first protective member; in experimental group 2, the overlap is 0%; in experimental group 3, the overlap is 20% of the length of the first protective member; in experimental group 4, the overlap is 50% of the length of the first protective member; and in experimental group 5, the overlap is 90% of the length of the first protective member. The batteries are adjusted to a state of charge (SOC) of 30% before the packaging is rolled off the assembly line to ensure that there are no "no good" batteries in each process and that the batteries roll off the assembly line normally. Five batteries of the same rating can be placed in a vibration chamber for 48 hours. The voltages of the batteries before and after vibration can be recorded, and the voltage differences of the five batteries before and after vibration can be calculated and averaged. The batteries in the control group were not subjected to vibration treatment. After vibration treatment, each battery in the experimental and control groups underwent CT (Computed Tomography) scans to observe any abnormalities in the tab morphology and any issues with tab intercalation. The experimental data is shown in Table 1 (the K value in Table 1 represents the voltage drop per unit time).

[0044] Table 1: Battery voltage difference and CT scan results.

[0045] Group Battery appearance 48h vibration voltage drop / mV <![CDATA[K value / mVh -1 > CT scan results Experimental Group 1 Meet appearance standards 1.532 0.032 No tab redundancy Experimental Group 2 Meet appearance standards 2.570 0.054 Slightly redundant Experimental Group 3 Meet appearance standards 2.433 0.051 No tab redundancy Experimental Group 4 Meet appearance standards 1.653 0.034 No tab redundancy Experimental Group 5 Meet appearance standards 1.547 0.032 No tab redundancy control group Meet appearance standards 1.531 0.032 No tab redundancy

[0046] Through the above experimental structure, a comparison of experimental groups 1 to 5 shows that as the overlap area between the second protective member and the first protective member gradually increases, the battery's 48-hour vibration voltage drop and K value gradually decrease, indicating that the battery's self-discharge gradually decreases and the tab is more firmly supported. By comparing experimental group 1 and the control group, the battery's 48-hour vibration voltage drop and K value are basically the same. The overlap area length of the second protective member and the first protective member is 70%, and the stability of the protective member support is at the same level as the battery's self-discharge when at rest. This shows that the 70% overlap area provides stable support during 48 hours of vibration.

[0047] Figure 4 A schematic oblique structural diagram of another exemplary electrode assembly 200 according to an embodiment of the present application is shown.

[0048] like Figure 4 As shown, the second protection member 414 and the first protection member 42 may have an overlapping area 416, and the length of the overlapping area 416 along the length direction of the cover assembly 104 is a. Figure 3BAs shown, along the length direction of the cover plate assembly 104, the length of the first protective member 42 is b. Based on the above experimental results, as shown in FIG. Figure 4 As shown, in some embodiments, the second protective member 414 and the first protective member 42 have an overlapping region 416. Along the length of the cover assembly 104, the length of the overlapping region 416 is a, and the length of the first protective member 42 is b, where a ≥ 50% b. As an optional embodiment, the length a of the overlapping region 416 can be greater than or equal to 70% of the length b of the first protective member 42, that is, a ≥ 70% b. This can make the tab more stable, significantly reducing the risk of tab insertion, further avoiding internal battery short circuits, increased self-discharge, and safety issues such as battery fires and explosions caused by tab insertion.

[0049] Figure 5 A schematic oblique structural diagram of another exemplary electrode assembly 200 according to an embodiment of the present application is shown.

[0050] like Figure 5 As shown, in some embodiments, the first portion 410 and the second portion 412 may partially overlap. This can further increase the stability of the protective member covering the first weld mark 208, making the first protective member 42 less likely to loosen as the battery life increases.

[0051] The electrode body 202 is formed by winding stacked electrode sheets and a diaphragm, and has a straight area 308 and a bent area 310. The tail end of the electrode sheet is located in the straight area 308, and a tail tape 306 is attached to the tail end.

[0052] It should be noted that the above embodiments are only described by taking an electrode assembly composed of multiple electrode bodies as an example. An electrode assembly composed of one electrode body can also constitute the battery 100 provided in this application and should also be included in the scope of protection of this application.

[0053] The present application also provides a battery pack, which includes the battery in the above technical solution. The battery may include one or more batteries, and the battery pack may form a battery pack.

[0054] Among them, the structure of the battery in the battery pack provided in this application is the same as that of the above-mentioned battery 100, and can bring the same or similar technical effects, which will not be described in detail here.

[0055] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present application (including the claims) is limited to these examples. Within the scope of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0056] The embodiments of the present application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the scope of protection of this application.

Claims

1. A battery comprising: a housing, wherein a first surface of the housing is open; a cover plate assembly covering the first surface, the cover plate assembly comprising a cover plate body and a pole insulated from the cover plate body; An electrode assembly is disposed in the housing, wherein the electrode assembly includes one or more electrode bodies, each of which has a tab; An adapter plate, the adapter plate being arranged between the tab and the cover plate assembly; The tab is welded to the adapter to form a first weld mark, the orthographic projection of the first weld mark on the cover plate assembly is located in a first area, and the first area is located at an end of the cover plate assembly away from the battery axis; The adapter is welded to the terminal to form a second weld mark, the orthographic projection of the second weld mark on the cover assembly is located in the second area, and the first area is located between the second area and the battery axis side; The battery further includes a first protective member and a second protective member, wherein the first protective member covers the first weld mark, and the second protective member covers the second weld mark and at least partially covers the first protective member.

2. The battery according to claim 1, wherein The thickness of the second protection member is greater than or equal to the thickness of the first protection member.

3. The battery according to claim 1, wherein The thickness of the battery is less than or equal to 50 mm.

4. The battery according to claim 1, wherein The electrode assembly includes a first electrode body and a second electrode body, the first electrode body has a first electrode tab, the second electrode body has a second electrode tab, the first electrode body and the second electrode body are arranged in parallel, and the first electrode tab and the second electrode tab are located on the same side of the electrode assembly; The first weld mark includes a first sub-weld mark and a second sub-weld mark, the first electrode tab is welded to the adapter to form the first sub-weld mark, and the second electrode tab is welded to the adapter to form the second sub-weld mark; The first protective member includes a first portion and a second portion, the first portion covers the first sub-weld print, and the second portion covers the second sub-weld print.

5. The battery according to claim 4, wherein The first portion and the second portion partially overlap.

6. The battery according to claim 1, wherein The second protection member and the first protection member have an overlapping area. Along the length direction of the cover plate assembly, the length of the overlapping area is a, and the length of the first protection member is b, wherein a≥50%b.

7. The battery according to claim 6, wherein a≥70%b.

8. The battery according to claim 1, wherein The area of ​​the first protective member is greater than or equal to the area of ​​the first weld mark, and the area of ​​the second protective member is greater than or equal to the area of ​​the second weld mark.

9. The battery according to claim 1, wherein The electrode body is formed by winding stacked pole pieces and diaphragms, and has a straight area and a bent area. The tail end of the pole piece is located in the straight area, and the tail end is pasted with a tail tape.

10. A battery pack comprising the battery according to any one of claims 1 to 9.

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