A square battery cell, battery, battery pack and electrical device

Abstract

The present application provides a square battery cell, a battery, a battery pack and an electrical device, relating to the technical field of batteries. The square battery cell includes: a battery cell body, the battery cell body extends along a first direction, along the first direction, the battery cell body includes a middle region and two end regions, the middle region is located between the two end regions, along a direction perpendicular to the first direction, the size of the end region is smaller than that of the middle region, so as to form an avoidance notch on the periphery of the end region, along the first direction, the length of the avoidance notch is d1; a protective member, the protective member is coated at the corner of the end region and partially extends into the avoidance notch, along the first direction, the length of the protective member is d2; wherein, d2 < d1, so that the corner of the battery cell body can be protected by the protective member, and the protective member can be prevented from occupying too much space inside the square battery cell for the expansion of the battery cell body.

Description

Technical Field

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

[0002] A battery cell is the basic unit of a battery, responsible for storing and releasing electrical energy. A battery cell typically consists of a casing and a cell body. The cell body includes a positive electrode, a separator, and a negative electrode stacked together, and is encapsulated within the casing.

[0003] During the manufacturing, transportation, and use of battery cells, they inevitably need to withstand external stresses, such as collisions and vibrations. For square battery cells, the main areas that bear these stresses are the corners of the cell body, which makes the corners of the cell body extremely vulnerable to damage. Utility Model Content

[0004] This application provides a square battery cell, battery, battery pack, and electrical device to solve the problem that the battery cell body of existing square batteries is extremely easy to be damaged at the corners.

[0005] In a first aspect, this application provides a square battery cell, comprising:

[0006] A battery cell body extends along a first direction, the battery cell body includes a central region and two end regions, the central region is located between the two end regions along the first direction, and the size of the end regions is smaller than the size of the central region along a direction perpendicular to the first direction, so as to form a clearance notch on the periphery of the end regions;

[0007] A protective element that covers the corner of the end region and is at least partially located within the clearance notch;

[0008] Wherein, along the first direction, the length of the clearance notch is d1, and the length of the protective component is d2. <d1。

[0009] Secondly, this application provides a battery comprising the square cell described in any one of the first aspects.

[0010] Thirdly, this application provides a battery pack including the square cells described in any of the second aspects or the batteries described in the third aspect.

[0011] Fourthly, this application provides an electrical device, including an electrical appliance and a battery as described in the second aspect or a battery pack as described in the third aspect, wherein the battery or the battery pack is used to supply power to the electrical appliance.

[0012] In the square battery cell, battery, battery pack, and electrical equipment provided by the above technical solution, the square battery cell is provided with a battery cell body and a protective component. The size of the end area of ​​the battery cell body is smaller than the size of the middle area, and an avoidance notch is formed on the periphery of the end area. The avoidance notch is arranged around the periphery of the end area. The protective component covers the corner of the battery cell body and is at least partially located within the avoidance notch. The protective component protects the battery cell body and prevents the force generated by external collisions, vibrations, etc. from being directly applied to the corner of the battery cell body, thereby reducing the probability of damage at the corner. At the same time, the length d2 of the protective component is smaller than the length d1 of the avoidance notch, preventing the protective component from extending to the outside of the middle area. Therefore, after the battery cell body is assembled into the encapsulation shell, the protective component does not occupy too much space for the expansion of the battery cell body, thereby preventing the protective component from affecting the performance of the battery cell body. Attached Figure Description

[0013] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0014] Figure 1 This is a schematic diagram of the structure of a square battery cell provided in an embodiment of this application;

[0015] Figure 2 An exploded view of a square battery cell provided in an embodiment of this application;

[0016] Figure 3 This is a schematic diagram of the structure of the battery cell body in the square battery cell provided in the embodiments of this application;

[0017] Figure 4 A schematic diagram of the assembly structure of the cell body and protective component in a square cell provided in an embodiment of this application;

[0018] Figure 5 This is a schematic diagram of the structure of the protective component in the square battery cell provided in the embodiments of this application;

[0019] Figure 6 This is a schematic diagram of the structure of the electrode sheet in the square battery cell provided in the embodiments of this application.

[0020] Explanation of reference numerals in the attached figures:

[0021] 100 - Cell body; 110 - End region; 120 - Middle region; 130 - Tab; 140 - Clearance notch; 150 - Electrode sheet; 151 - Current collector; 152 - Active material layer;

[0022] 200 - Protective component; 210 - First wall; 220 - Second wall; 230 - Third wall; 240 - Fourth wall;

[0023] 300 - Package housing; 310 - Electrode terminal; 320 - Cover plate assembly.

[0024] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the specific technical solutions of this application will be further described in detail below with reference to the accompanying drawings of the embodiments of this application. The following embodiments are used to illustrate this application, but are not intended to limit the scope of this application.

[0026] In the embodiments of this application, 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 indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more.

[0027] Furthermore, in the embodiments of this application, directional terms such as "upper," "lower," "left," and "right" are defined relative to the positions in which the components are schematically placed in the accompanying drawings. It should be understood that these directional terms are relative concepts, used for relative description and clarification, and can change accordingly depending on the position of the components in the accompanying drawings.

[0028] In the embodiments of this application, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can mean a fixed connection, a detachable connection, or an integral part; it can mean a direct connection or an indirect connection through an intermediate medium.

[0029] In embodiments of this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0030] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0031] As mentioned in the background section, for a square battery cell, the positive electrode, separator, and negative electrode are stacked alternately to form a rectangular battery cell body, which is then encapsulated in a casing.

[0032] During manufacturing, transportation, and use, prismatic battery cells inevitably encounter external stresses such as impacts and vibrations. This makes the four corners of the cell body—the edges extending along the thickness direction at the end of the cell—extremely vulnerable to compression, leading to damage at these corners. This can cause internal short circuits and other problems, affecting not only the performance of the prismatic battery cells but also posing safety hazards.

[0033] A common approach is to directly cover the corner with cushioning material to reduce the impact force at the corner, thereby protecting the battery cell itself.

[0034] However, in actual use, the cell body may undergo volume changes. For example, when lithium ions are inserted into and extracted from the electrode material, the electrode material may expand and contract. If the internal space of the package is insufficient, the package may deform or crack when the cell body expands, increasing the risk of electrolyte leakage or cell explosion. Therefore, sufficient space needs to be left inside the package to allow the cell body to expand.

[0035] After covering the corners of the battery cell with cushioning material, the cushioning material will occupy a lot of space, making it impossible to reserve enough space inside the packaging shell for the expansion of the battery cell, thus affecting the performance of the battery cell.

[0036] In response, this application provides a square battery cell where the size of the end region of the battery cell body is smaller than the size of the middle region of the battery cell body. This results in a clearance notch being formed on the periphery of the end region of the battery cell body. A protective member covers the corner of the battery cell body and is at least partially located within the clearance notch. At the same time, the length of the clearance notch is greater than the length of the protective member, so that the protective member does not extend to the outside of the middle region of the battery cell body. This avoids the protective member occupying too much space inside the encapsulation shell, leaving sufficient expansion space for the battery cell body and preventing the protective member from affecting the performance of the battery cell body.

[0037] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0038] This application provides a square battery cell; please refer to [link / reference]. Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, it includes a battery cell body 100 and a protective component 200.

[0039] The length direction of the cell body 100 is the first direction (Z direction), the thickness direction of the cell body 100 is the Y direction, the width direction of the cell body 100 is the X direction, and the two end faces of the cell body 100 that are parallel to the XZ plane are its two surfaces at both ends in the thickness direction.

[0040] The dimensions at both ends of the battery cell body 100 are smaller than the dimensions at the middle. Specifically, along the Z-direction, the battery cell body 100 can be divided into three regions: end regions 110 at both ends and a middle region 120 in the middle. Along the Y-direction, the thickness of the end region 110 is less than the thickness of the middle region 120, and along the X-direction, the width of the end region 110 is less than the width of the middle region 120. Due to the dimensional difference between the end region 110 and the middle region 120, a clearance notch 140 is formed in the end region 110. This clearance notch 140 is located around the periphery of the end region 110. Along the Y-direction, the length of the clearance notch 140 is half the difference between the thickness of the middle region 120 and the thickness of the end region 110. Along the X-direction, the length of the clearance notch 140 is half the difference between the width of the middle region 120 and the width of the end region 110.

[0041] The end faces of the battery cell body 100 along the Z direction are two surfaces parallel to the XY plane, the end faces of the battery cell body 100 along the X direction are two surfaces parallel to the YZ plane, and the corner of the battery cell body 100 is a corner formed by the intersection of the surface parallel to the XY plane, the surface parallel to the YZ plane, and the surface parallel to the XZ plane.

[0042] The protective component 200 covers the corner of the battery cell body 100 and is at least partially located within the clearance notch 140. That is, the protective component 200 can be fully or partially embedded within the clearance notch 140. The protective component 200 can protect the corner of the battery cell body 100 and reduce the probability of damage to the corner of the battery cell body 100.

[0043] Among them, the protective member 200 and the surface of the battery cell body 100 can be connected by bonding or other common methods, as long as the corners of the battery cell body 100 can be effectively protected.

[0044] It should be noted that there can be four protective members 200, which are respectively arranged at the four corners of the battery cell body 100. There can also be two protective members 200, with one arranged in each of the two end regions 110, and one protective member 200 covering two corners of the battery cell body 100.

[0045] The material of the protective member 200 can be ordinary plastic, or plastic with certain buffering ability, such as polyethylene foam, polyurethane foam, thermoplastic elastomer, etc. For the convenience of assembly, the protective member 200 can also be an insulating tape, which can be directly wound around the outside of the end region 110. Of course, when using the insulating tape as the protective member 200, multiple layers can be pasted.

[0046] In addition, along the Z direction, the length of the avoidance notch 140 is d1, and the length of the protective member 200 is d2, and d2 < d1. This makes the protective member 200 not extend to the surface of the middle region 120, but completely within the avoidance notch 140, which can prevent the protective member 200 from squeezing the space for the battery cell body 100 to expand. Thus, it can not only protect the corners of the battery cell body 100, but also not affect the expansion space of the battery cell body 100, thereby avoiding affecting the performance of the battery cell body 100.

[0047] In some embodiments of the present application, please refer to Figure 2 and Figure 6 As shown, the battery cell body 100 includes a plurality of electrode sheets 150. The plurality of electrode sheets 150 can be stacked along the thickness direction of the battery cell body 100, that is, the Y direction, to form a square laminated battery cell, or the plurality of electrode sheets 150 can be made into a square wound battery cell.

[0048] The electrode sheet 150 includes a current collector 151 and an active material layer 152. The active material layer 152 covers at least one surface of the current collector 151, and this surface is parallel to the XZ plane. Both the current collector 151 and the active material layer 152 extend along the X direction. The electrode sheet 150 is further divided into a positive electrode sheet and a negative electrode sheet. The difference is that the electrode materials used for the corresponding active material layers 152 of the positive electrode sheet and the negative electrode sheet are different. The positive electrode sheet and the negative electrode sheet are alternately stacked in sequence, and the positive electrode sheet and the negative electrode sheet are separated by a separator.

[0049] Among them, the separator can play a role in preventing the electrodes from directly contacting and causing a short circuit, and at the same time allows ions to pass through to maintain the normal operation of the battery cell body 100. The selection of the separator material is crucial for the performance, safety and life of the battery cell body 100.

[0050] The diaphragm can be made of commonly used membranes such as polyethylene (PE) membrane, polypropylene (PP) membrane, PP / PE / PP three-layer composite membrane, ceramic coated membrane (a layer of ceramic material, such as alumina or silicon dioxide, is coated on the basis of polyolefin diaphragm), or composite membrane, and the specific type can be adjusted according to the actual situation.

[0051] The selection of electrode materials used for the active material layer 152 includes at least the following:

[0052] For example, in a lithium-ion battery cell, when the electrode sheet 150 is used as a negative electrode, the electrode material used for the active material layer 152 can be lithium cobalt oxide (...). Lithium iron phosphate () ), lithium manganese oxide ( Nickel-cobalt-manganese oxide (NCM or NMC) or nickel-cobalt-aluminum oxide (NCA).

[0053] When the electrode sheet 150 is used as a positive electrode sheet, the electrode material used for the active material layer 152 can be graphite, silicon-based material, or hard carbon or soft carbon.

[0054] For example, in a lead-acid battery cell, when the electrode sheet 150 is used as the negative electrode, the electrode material used for the active material layer 152 can be lead dioxide (lead oxide). ).

[0055] When the electrode sheet 150 is used as a positive electrode sheet, the electrode material used for the active material layer 152 can be spongy lead.

[0056] For example, in a nickel-metal hydride battery cell, when the electrode sheet 150 is used as the negative electrode, the electrode material used for the active material layer 152 can be nickel hydroxide (NiMH). ).

[0057] When the electrode sheet 150 is used as a positive electrode sheet, the electrode material used in the active material layer 152 can be a metal hydride.

[0058] It should be noted that the selection of electrode materials used in the active material layer 152 is only an example and not a limitation. The specific selection can be adjusted according to the actual situation.

[0059] In order to make the size of the end region 110 of the cell body 100 smaller than the size of the middle region 120 to form the clearance notch 140, the coating thickness at both ends of the active material layer 152 can be less than the coating thickness in the middle, so that the thickness at the end of each electrode sheet 150 is less than the thickness in the middle. Here, the end refers to the region corresponding to the clearance notch 140, and the remainder is the middle.

[0060] It should be noted that the size of the end region 110 of the cell body 100 is smaller than the size of the middle region 120 of the cell body 100. This can also be achieved in other ways; the above is just an example.

[0061] In some embodiments of this application, the square battery cell also includes a packaging shell 300, in which the battery cell body 100 and the protective component 200 are both located within the packaging shell 300 and protected by the packaging shell 300.

[0062] The shape of the encapsulation shell 300 is usually adapted to the shape of the cell body 100, and there is generally a gap between some areas and the cell body 100 to allow space for the expansion of the cell body 100.

[0063] It should be noted that the material of the encapsulation shell 300 can be selected according to the actual situation, such as metal materials (aluminum, steel, nickel, etc.) or plastic materials.

[0064] Furthermore, the electrode sheet 150 is also provided with tabs 130. Correspondingly, the tabs 130 are also divided into positive tabs and negative tabs. The positive tabs are electrically connected to the positive electrode sheet, and the negative tabs are electrically connected to the negative electrode sheet. The positive tabs and negative tabs can be located at both ends of the battery cell body 100, or at the same end of the battery cell body 100. The specific location can be adjusted according to the actual situation.

[0065] In order to connect with external circuits, the package 300 needs to be provided with electrode terminals 310. The electrode terminals 310 are also divided into positive electrode terminals and negative electrode terminals, which are soldered to the positive electrode tab and the negative electrode tab respectively to conduct electricity.

[0066] Accordingly, the encapsulation shell 300 is typically provided with a cover plate assembly 320 at the end where the electrode terminals 310 are located. The end of the encapsulation shell 300 is open, and the cover plate assembly 320 closes the opening of the encapsulation shell 300 to isolate it from the external environment. The cover plate assembly 320 is usually of a certain strength and can be made of metal to avoid deformation. The electrode terminals 310 are fixed on the cover plate assembly 320. After the cover plate assembly 320 is provided, it is convenient to install the square battery cell and to weld the electrode terminals 310 and the square battery cell.

[0067] The minimum distance d3 between the protective component 200 and the electrode tab 130 is 5mm-40mm. This ensures a suitable distance between the protective component 200 and the electrode tab 130. When the electrode tab 130 is subsequently welded to the electrode terminal 310 that conducts external circuitry, the protective component 200 can be protected from the high temperature of welding, and the protective component 200 can also prevent the welding between the electrode tab 130 and the electrode terminal 310 from being blocked.

[0068] In some embodiments of this application, the length of the clearance notch 140 along the thickness direction of the cell body 100 is greater than or equal to the length of the protective member 200.

[0069] For example, please see Figure 5 As shown, the protective component 200 may include a first wall 210, a second wall 220, a third wall 230, and a fourth wall 240. The first wall 210 is parallel to the YZ plane, the second wall 220 is parallel to the XY plane, and the third wall 230 and the fourth wall 240 are both parallel to the XZ plane. The first wall 210 and the second wall 220 intersect, and also intersect with the third wall 230 and the fourth wall 240, so as to cover the corner of the battery cell body 100.

[0070] In the Y direction, the depth of the area corresponding to the clearance notch 140 is greater than the thickness of the third wall 230 and the fourth wall 240, so that the third wall 230 and the fourth wall 240 will not protrude beyond the clearance notch 140. The overall size of the protective component 200 in the Y direction is smaller than the size of the central area 120 of the cell body 100. This ensures that the protective component 200 will not occupy the expansion space of the cell body 100 in the Y direction, thereby avoiding affecting the performance of the cell body 100.

[0071] For example, the first wall 210 and the second wall 220 can also be square structures with a thickness that matches the thickness of the cell body 100, while the third wall 230 and the fourth wall 240 are triangular. The width of the third wall 230 and the fourth wall 240 in the X direction gradually decreases along the direction from the middle region 120 to the end region 110. That is, the further away from the corner of the cell body 100, the smaller the size of the third wall 230 and the fourth wall 240. This can effectively protect the corner of the cell body 100 while reducing the volume and weight of the protective member 200.

[0072] Meanwhile, the third wall 230 and the fourth wall 240 are set as a triangle, and the first wall 210 and the second wall 220 are connected through the third wall 230 and the fourth wall 240, which can play a reinforcing role and improve the stability of the protective component 200.

[0073] Furthermore, the length d1 of the clearance gap 140 is 20mm-60mm.

[0074] The length of the commonly used cell body 100 is 80mm-60mm. Setting the length d1 of the clearance notch 140 to 20mm-60mm notches notches 140 to a certain height facilitates the installation and fixing of the protective component 200, while also controlling the reduction of the active material layer 152 appropriately to ensure the performance of the cell body 100.

[0075] Correspondingly, the length d2 of the protective component 200 is 10mm-50mm, which makes the length difference between the protective component 200 and the clearance notch 140 appropriate. This not only prevents the protective component 200 from squeezing the space of the power supply core body 100 inside the encapsulation shell 300, but also facilitates the installation of the protective component 200.

[0076] Furthermore, the ratio between the length d2 of the protective component 200 and the length of the cell body 100 is 0.05-0.6. Based on the ratio and the length of the cell body 100, the length of the protective component 200 can be adaptively adjusted. While avoiding the protective component 200 from affecting the volumetric energy density of the square cell, the size of the protective component 200 can be made appropriate, which can better protect the corners of the cell body 100.

[0077] This application also provides a battery, including the square cell described in the above embodiments.

[0078] The battery also includes a casing, which can encapsulate one or more square cells. When encapsulating multiple square cells, they can be connected in series (to increase voltage) or in parallel (to increase capacity).

[0079] This application also provides a battery pack, including the square cells or batteries described in the above embodiments.

[0080] It should be noted that the battery pack also includes components such as a thermal management system for controlling battery temperature, and it may include one or more batteries, or one or more prismatic cells, with multiple batteries connected in series or in parallel, or multiple prismatic cells connected in series or in parallel.

[0081] This application also provides an electrical device, including an electrical device and a battery or battery pack as described in the above embodiments, wherein the battery or battery pack is used to supply power to the electrical device.

[0082] It should be noted that electrical equipment includes, but is not limited to, electric vehicles, hybrid vehicles, medical equipment, aerospace equipment, energy storage systems, and home electronic products that require power from batteries or battery packs.

[0083] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the utility models disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0084] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A square battery cell, characterized in that, include: A battery cell body (100) extends along a first direction, the battery cell body (100) includes a central region (120) and two end regions (110), the central region (120) is located between the two end regions (110) along the first direction, and the size of the end regions (110) is smaller than the size of the central region (120) in a direction perpendicular to the first direction, so as to form a clearance notch (140) on the periphery of the end regions (110); A protective element (200) covers the corner of the end region (110) and is at least partially located within the clearance notch (140); Wherein, along the first direction, the length of the clearance notch (140) is d1, and the length of the protective component (200) is d2. <d1。 2. The square battery cell according to claim 1, characterized in that, The battery cell body (100) includes a plurality of electrode sheets (150), each electrode sheet (150) including a current collector (151) and an active material layer (152), the active material layer (152) being located on at least one surface of the current collector (151), both the current collector (151) and the active material layer (152) extending along the first direction, the thickness of the end of the active material layer (152) being less than the thickness of the middle part of the active material layer (152).

3. The square battery cell according to claim 1, characterized in that, The end of the battery cell body (100) is provided with a tab (130), and the minimum distance between the tab (130) and the protective component (200) is 5mm-40mm.

4. The square battery cell according to claim 1, characterized in that, Along the thickness direction of the cell body (100), the length of the clearance notch (140) is greater than or equal to the length of the protective member (200).

5. The square battery cell according to claim 1, characterized in that, The ratio of d2 to the length of the cell body (100) is 0.05-0.

6.

6. The square battery cell according to claim 1, characterized in that, The protective component (200) is a plastic component, or the protective component (200) is an insulating tape pasted on the surface of the battery cell body (100).

7. The square battery cell according to claim 1, characterized in that, d1 is 20mm-60mm.

8. The square battery cell according to claim 1, characterized in that, d2 is 10mm-50mm.

9. The square battery cell according to any one of claims 1-8, characterized in that, It also includes a packaging shell (300), and the battery cell body (100) and the protective component (200) are both located inside the packaging shell (300).

10. A battery, characterized in that, Includes the square battery cell as described in any one of claims 1-9.

11. A battery pack, characterized in that, Includes the square battery cell as described in any one of claims 1-9 or the battery as described in claim 10.

12. An electrical appliance, characterized in that, It includes an electrical device, and the battery of claim 10 or the battery pack of claim 11, the battery or the battery pack being used to supply power to the electrical device.

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