Cylindrical battery and battery pack

Abstract

The utility model provides a cylindrical battery and a battery pack, the cylindrical battery comprises a shell and a battery cell assembly, the shell comprises a side plate and a bottom plate, and the battery cell assembly is arranged in the shell; the bottom plate is provided with a nick, so that the extrusion force generated by the shell to the bottom plate is relieved through the nick. According to the embodiment of the invention, the nicks are arranged on the bottom plate of the battery, and the nicks play a role in relieving the pressure caused by the expansion of the battery by relieving the contact pressure between the bottom plate and the shell. When the battery expands and the shell deforms, the two narrowed ends of the shell generate extrusion force on the bottom plate, and due to the existence of the nicks, the extrusion force of the shell on the bottom plate can be buffered. The effect can reduce the risk that the bottom of the battery protrudes or even is broken due to expansion, so that the stability of the battery is improved.

Description

Technical Field

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

[0002] At present, lithium-ion batteries have the advantages of high specific energy, many cycles and long storage time. They are not only widely used in portable electronic devices such as mobile phones, digital cameras and laptops, but also widely used in large and medium-sized electric equipment such as electric vehicles, electric bicycles and electric tools. Therefore, the safety performance requirements for lithium-ion batteries are getting higher and higher.

[0003] In the related art, during the use of the battery, as the number of times the battery is charged increases, the battery swells, which easily leads to the occurrence of a battery convex bottom phenomenon.

[0004] Therefore, how to effectively reduce the probability of battery convex bottom phenomenon caused by battery swelling to improve battery stability is a technical problem that urgently needs to be solved in the current battery technology field. Utility Model Content

[0005] The embodiments of the present application provide a cylindrical battery and a battery pack, which can effectively reduce the probability of battery convex bottom phenomenon caused by battery swelling, so as to improve the technical problem of battery stability.

[0006] In a first aspect, an embodiment of the present application provides a cylindrical battery, comprising:

[0007] a housing, including side panels and a bottom panel;

[0008] A battery cell assembly is disposed in the housing;

[0009] The bottom plate is provided with notches so as to relieve the squeezing force generated by the shell on the bottom plate through the notches.

[0010] In one embodiment, the notch is located on a side of the bottom plate away from the battery cell assembly.

[0011] In one embodiment, the notch is located on a side of the bottom plate close to the battery cell assembly.

[0012] In one embodiment, the score comprises at least one annular score.

[0013] In one embodiment, the score comprises at least one wavy score.

[0014] In one embodiment, the depth of the notch ranges from 30% to 90% of the thickness of the bottom plate.

[0015] In one embodiment, the width of the notch ranges from 0.01 mm to 0.2 mm.

[0016] In one embodiment, the width of the bottom surface of the notch is smaller than the width of the notch opening.

[0017] In one embodiment, a buffer substance is further included, and the buffer substance is disposed in the notch.

[0018] In a second aspect, an embodiment of the present application provides a battery pack, comprising a plurality of cylindrical batteries as described and a BMS management system connected to the cylindrical batteries.

[0019] Beneficial effects of the embodiments of the present application:

[0020] In the embodiments of the present application, notches are provided on the bottom plate of the battery housing. The notches relieve the pressure caused by battery expansion by reducing the contact pressure between the bottom plate and the side plate. When the battery cell assembly in the battery expands, the side plate deforms, and its narrowed ends exert an extrusion force on the bottom plate. Due to the presence of notches, the extrusion force of the side plate on the bottom plate can be buffered. This effect can reduce the risk of battery convexity or even rupture due to expansion, thereby improving the stability of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 is a schematic diagram of a front cross-sectional structure of a cylindrical battery provided in an embodiment of the present application;

[0023] Figure 2 is a schematic diagram of a top view of the bottom plate provided in an embodiment of the present application;

[0024] Figure 3 is a schematic diagram of the structure of the notch on the bottom plate provided in the embodiment of the present application;

[0025] Figure 4 It is another schematic diagram of the front cross-sectional structure of the cylindrical battery provided in the embodiment of the present application. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise stated, the directional words such as "upper" and "lower" used generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the accompanying drawings; while "inside" and "outside" refer to the outline of the device.

[0027] Because in the related art, during the use of the battery, as the number of times the battery is charged increases, the battery swells, which easily leads to the occurrence of a convex bottom phenomenon of the battery. For this reason, the embodiment of the present application provides a cylindrical battery and a battery pack, so that by setting a notch on the bottom plate of the battery casing, the role of this notch is to relieve the pressure caused by the expansion of the battery by reducing the contact pressure between the bottom plate and the side plate. When the battery cell assembly in the battery expands, the side plate is deformed, and its narrowed two ends will produce an extrusion force on the bottom plate. Due to the presence of the notch, the extrusion force of the side plate on the bottom plate can be buffered. This effect can reduce the risk of a convex bottom or even rupture of the battery due to expansion, thereby improving the stability of the battery. For specific solutions, please refer to the following specific description.

[0028] It should be noted that, hereinafter, the terms "battery module", "battery", "battery element", "battery cell" and "battery pack" can be used interchangeably and can refer to any of a variety of different rechargeable battery chemistries and structures, including but not limited to lithium ion (e.g., lithium ion phosphate, lithium cobalt oxide, lithium iron phosphate, other lithium metal oxides, etc.), lithium ion polymer, nickel metal hydride, nickel cadmium, nickel metal hydride, nickel zinc, silver zinc or other battery types / structures. The term "electric vehicle" is used here to refer to a fully electric vehicle, also known as an EV, a plug-in hybrid vehicle, also known as a PHEV, or a hybrid electric vehicle (HEV), wherein the hybrid vehicle uses multiple propulsion sources, one of which is an electric drive system. It should be understood that the same figure numbers are used in multiple figures to refer to the same components or components of equivalent functions, and various modifications to the preferred embodiments, general principles and features described herein will be obvious to those skilled in the art. In addition, the drawings are intended only to illustrate the scope of the present application and not to limit it and should not be considered to be drawn to scale.

[0029] Embodiments of the present application are generally applicable to systems using electric motors, and more specifically, but not exclusively, to electric vehicles using multiphase electric motors (e.g., inductive motors). Electric vehicles use one or more stored energy sources such as battery packs to provide electrical energy to the vehicle. This energy is at least partially used to propel the vehicle. The stored energy can also be used to provide energy required by other vehicle systems, such as vehicle lighting, vehicle partitionable heating, ventilation and air conditioning (HVAC) systems, auxiliary control systems (e.g., sensors, displays, navigation systems, etc.), vehicle entertainment systems (e.g., radio, DVD, MP3, etc.), etc. Conventional electric vehicles include passenger vehicles and vehicles designed to transport goods, examples of which include passenger cars, trucks, electric bicycles, and recreational boats. Electric vehicles also include dedicated work vehicles and carts, some of which can be integrated with forklifts, scissor lifts, lifting and / or articulated boom aerial work platforms, street cleaning systems, conveyor belts, and flatbed handling platforms.

[0030] For details, please refer to Figure 1-4 , Figure 1 It is a front cross-sectional schematic diagram of a cylindrical battery provided in an embodiment of the present application, wherein the cylindrical battery specifically includes a shell and a battery cell assembly 200, wherein the shell includes a side plate 100 and a bottom plate 300, wherein the battery cell assembly 200 is arranged in the side plate 100; the bottom plate 300 has a notch 301, so as to remove the extrusion force generated by the side plate 100 on the bottom plate 300 through the notch 301.

[0031] In the present application embodiment, Figure 4 As shown, the bottom plate 300 and the side plate 100 may also be integrally formed, and may be specifically configured according to actual needs.

[0032] The side plate 100 is usually made of metal, such as steel or aluminum alloy. The main function of the side plate 100 is to provide protection and support, and to prevent the physical contact between the internal components of the battery and the external environment.

[0033] The battery cell assembly 200 may include positive and negative electrodes, an electrolyte and a diaphragm. Among them, the positive and negative electrodes are important components of the battery. Usually, the positive electrode is composed of a lithium compound (such as lithium iron phosphate) and a conductive agent (such as graphite), while the negative electrode is usually composed of a graphite material. It should be noted that the present application is mainly aimed at cylindrical lithium-ion batteries using a silicon-carbon negative electrode system. The electrolyte is an important component in a cylindrical lithium battery, and the electrolyte may be composed of an organic solution (such as a carbonate solution) or a polymer gel (such as a polymer electrolyte). The electrolyte is responsible for the transmission of ions, allowing the battery to perform charge and discharge reactions. The diaphragm is located between the positive and negative electrodes to prevent direct contact between the positive and negative electrodes. The diaphragm can be made of a polymer material, has good ion transmission and safety performance, and can prevent the battery from short-circuiting. In addition, the battery may also include a spring sheet, which is located at the positive or negative electrode of the battery, and is used to connect the battery to an external circuit to achieve battery charging and discharging.

[0034] It should be noted that the above structure constitutes the basic structure of cylindrical lithium batteries. Cylindrical lithium batteries of different models and specifications may differ in details, but the overall architecture is roughly similar. The above structure can make cylindrical lithium batteries have higher energy density and stability.

[0035] In the embodiment of the present application, a notch 301 is provided on the bottom plate 300 of the battery housing. The notch 301 relieves the pressure caused by battery expansion by reducing the contact pressure between the bottom plate 300 and the side plate. When the battery cell assembly 200 in the battery expands, the side plate 100 is deformed, and its narrowed ends exert a squeezing force on the bottom plate 300. Due to the presence of the notch 301, the squeezing force of the side plate 100 on the bottom plate 300 can be buffered. This effect can reduce the risk of battery convexity or even rupture due to expansion, thereby improving the stability of the battery.

[0036] In some specific embodiments, the notch 301 may be located on a side of the bottom plate 300 away from the battery cell assembly 200. And / or the notch 301 is located on a side of the bottom plate 300 close to the battery cell assembly 200. In this way, the notch 301 can be flexibly arranged, which reduces the processing difficulty and improves the preparation efficiency.

[0037] In some embodiments of the present application, the notch 301 includes at least one annular notch 301. The at least one notch may be one, two, or more than two.

[0038] When the top view of the bottom plate 300 is a target circle similar to a circle, the annular notch 301 can be concentric with the target circle, and the multiple annular notches 301 are all concentric circles, and their radii increase successively, but the radius of the ring is smaller than the radius of the target circle.

[0039] In a specific embodiment, Figure 2-3 As shown, the notches 301 are three annular notches 301 , and the three annular notches 301 are designed as concentric circles, so that the squeezing force generated by the side plate 100 on the bottom plate 300 can be more evenly removed.

[0040] In some other embodiments, the plurality of annular notches 301 may be in a mutually separated positional relationship, or may be in an intersecting or containing relationship.

[0041] In some embodiments of the present application, the notch 301 includes at least one wavy notch 301. The at least one wavy notch 301 may be one, two, or more than two, which may be specifically set according to actual needs.

[0042] In a specific embodiment, multiple wave shapes can be arranged at intervals or in an intersecting distribution. In the interval setting scheme, equal spacing can be adopted or not, but equal spacing is preferred. In this way, the extrusion force generated by the side panel 100 on the bottom panel 300 can be better and evenly removed.

[0043] In order to ensure that the strength of the bottom plate 300 meets the requirements and can relieve the squeezing force exerted by the side plate 100, in the embodiment of the present application, the depth range of the notch 301 is set to 30% to 90%, preferably 85%, of the thickness of the bottom plate 300. The width range of the notch 301 is set to 0.01 mm to 0.2 mm, preferably 0.1 mm.

[0044] In order to further improve the pressure relief effect of the notch 301, in some embodiments of the present application, the width of the bottom surface of the notch 301 is set to be smaller than the width of the opening of the notch 301, so that the cross-section of the notch 301 is an inverted trapezoid. In this way, the bending angle of the bottom plate 300 can be further increased, thereby improving the pressure relief space and pressure relief capacity.

[0045] The setting of the notch 301 will still affect the overall structural stability and strength of the bottom plate 300 to a certain extent. In order to make up for this defect, in the embodiment of the present application, the cylindrical battery is also provided with a buffer material (not shown in the figure), which is arranged in the notch 301 to fill the gap between the notches 301. The buffer material has certain elasticity and buffering properties. Specifically, the buffer material may include a polymer material: the polymer material has good elasticity and buffering properties, and can effectively fill the gap between the notches 301. For example, polymer materials such as polyurethane, silicone rubber, and acrylic resin. Elastic material: The elastic material has good resilience and buffering properties and can absorb shock and vibration. For example, rubber (such as natural rubber, nitrile rubber, propylene rubber, etc.) and foam material (such as polyurethane foam, polyethylene foam), etc. Gel material: The gel material has a polymer network structure and good compressibility, and can provide a good buffering effect. For example, silicone gel, polysiloxane gel, etc. Film material: Some film materials can also be used as buffer substances, such as polyester film, polyether ketone film, etc. These films have high flexibility and stretchability and can play a certain buffering role when filling the gap of the notch 301 .

[0046] It should be noted that when selecting a buffer material, factors such as mechanical properties, high temperature resistance, and chemical stability may be considered to ensure that the buffer material can effectively fill the gaps between the notches 301 and provide sufficient buffering effect. The specific selection of suitable materials requires comprehensive consideration based on the design requirements and application environment of the battery.

[0047] In the embodiment of the present application, the notch 301 may also serve as an explosion-proof notch. Preferably, the cylindrical battery has both an explosion-proof notch and a notch 301 for removing the extrusion force generated by the shell on the bottom plate.

[0048] An embodiment of the present application also provides a battery pack, which includes a plurality of cylindrical batteries and a BMS management system connected to the cylindrical batteries.

[0049] The BMS (Battery Management System) is a system designed specifically to monitor, control and protect battery packs. It plays the following important roles in battery packs:

[0050] 1. Monitor battery status: BMS can monitor the battery pack's voltage, current, temperature, SOC (State of Charge) and other parameters in real time to understand the working status and health of the battery pack.

[0051] 2.Balanced battery pack: There may be imbalance between each battery cell in the battery pack, resulting in shortened battery life or reduced performance. BMS can balance the voltage difference within the battery pack by controlling the charging and discharging process of each battery cell, thereby improving the overall performance and life of the battery pack.

[0052] 3. Control the charging and discharging process: BMS can control the battery charging and discharging process to ensure that the charging and discharging operations are performed within a safe range. It can implement reasonable and efficient charging and discharging management of the battery according to the preset charging and discharging strategies and working conditions to maximize the battery life and improve energy utilization.

[0053] 4. Health diagnosis and protection: BMS can diagnose the health status of the battery pack, timely detect and protect the battery pack from damage due to abnormal conditions such as overcurrent, overvoltage, overtemperature, undervoltage, short circuit, etc. It can ensure the safe operation of the battery pack by disconnecting the charge and discharge circuit or taking other protective measures.

[0054] 5. Data recording and communication: BMS can record the operating data of the battery pack, including charge and discharge history, fault records and status parameters, etc., to provide a basis for subsequent data analysis and troubleshooting. At the same time, BMS can also exchange data with other devices or systems through the communication interface to achieve remote monitoring and control of the battery pack.

[0055] In general, the BMS battery management system plays a vital role in the monitoring, balancing, control, protection and data management of the battery pack, helping to improve the performance, safety and life of the battery pack while providing comprehensive battery management and control functions.

[0056] It should be noted that in addition to the cylindrical batteries and BMS battery management system mentioned above, the battery pack may also include other components, such as sensor equipment.

[0057] In the embodiment of the present application, a notch 301 is provided on the bottom plate 300 of the battery. The notch 301 relieves the pressure caused by the expansion of the battery by reducing the contact pressure between the bottom plate 300 and the side plate 100. When the battery cell assembly 200 in the battery expands, when the side plate 100 is deformed, its narrowed ends will exert an extrusion force on the bottom plate 300. Due to the presence of the notch 301, the extrusion force of the side plate 100 on the bottom plate 300 can be buffered. This effect can reduce the risk of the battery convex bottom or even rupture due to expansion, thereby improving the stability of the battery.

[0058] The embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A cylindrical battery, characterized in that: include: a housing, including side panels and a bottom panel; A battery cell assembly is disposed in the housing; The bottom plate is provided with notches so as to relieve the squeezing force generated by the side plates on the bottom plate through the notches; Wherein, the notch is located on a side of the bottom plate close to the battery cell assembly.

2. The cylindrical battery according to claim 1, characterized in that: The notch is located on a side of the bottom plate away from the battery core assembly.

3. The cylindrical battery according to claim 1, characterized in that: The score includes at least one annular score.

4. The cylindrical battery according to claim 1, characterized in that: The score includes at least one wavy score.

5. The cylindrical battery according to any one of claims 1 to 4, characterized in that: The depth of the notch ranges from 30% to 90% of the thickness of the base plate.

6. The cylindrical battery according to any one of claims 1 to 4, characterized in that: The width of the notch ranges from 0.01 mm to 0.2 mm.

7. The cylindrical battery according to any one of claims 1 to 4, characterized in that: The width of the bottom surface of the notch is smaller than the width of the notch opening.

8. The cylindrical battery according to any one of claims 1 to 4, characterized in that: Also included is a buffer substance, which is disposed in the notch.

9. A battery pack, characterized in that: The invention comprises a plurality of cylindrical batteries as described in any one of claims 1 to 8 and a BMS management system connected to the cylindrical batteries.

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