Battery cell and battery pack

Abstract

The utility model provides a battery cell and a battery pack, the battery cell comprises a shell, a roll core and a cold plate, and the roll core and the cold plate are accommodated in the shell; the roll core comprises a positive pole piece, a first isolating membrane, a negative pole piece and a second isolating membrane which are sequentially stacked, the roll core is wound along the outer surface of the cold plate, and the cold plate is located on the side, away from the negative pole piece, of the second isolating membrane; the cold plate is used for exchanging heat with the roll core, the interior of the cold plate comprises a first cavity, and the first cavity is used for containing a heat exchange medium. According to the battery cell and the battery pack provided by the embodiment of the invention, the heat exchange effect of the battery cell can be improved, and the use safety of the battery cell is improved.

Description

Technical Field

[0001] The present application relates to the field of new energy technology, and more specifically, to a battery cell and a battery pack. Background Art

[0002] Lithium-ion and sodium-ion batteries generate a lot of heat during the charging and discharging process. The accumulated heat causes the temperature of the battery system to rise, which will not only aggravate the battery side reactions and affect the performance and life of the battery pack, but also cause safety hazards. Therefore, the battery system is usually designed with a cooling system, such as air cooling, liquid cooling and other structural modules to assist in battery heat dissipation. The battery system cooling solution currently commonly used in the industry is very likely to cause temperature differences inside the battery cell, which affects the life of the battery cell to a certain extent, and with the trend of increasing battery cell size, the cooling demand of the battery system is gradually increasing. Therefore, how to improve the heat exchange effect of the battery cell has become a problem that needs to be solved urgently. Utility Model Content

[0003] The present application provides a battery cell and a battery pack, which can enhance the heat exchange effect of the battery cell and improve the safety of the battery cell use.

[0004] In a first aspect, a battery cell is provided, comprising a shell, a winding core and a cold plate, wherein the winding core and the cold plate are accommodated inside the shell; the winding core comprises a positive electrode sheet, a first isolation film, a negative electrode sheet and a second isolation film stacked in sequence, the winding core is wound along the outer surface of the cold plate, and the cold plate is located on a side of the second isolation film away from the negative electrode sheet; the cold plate is used for heat exchange with the winding core, and the cold plate comprises a first cavity inside, and the first cavity is used to accommodate a heat exchange medium.

[0005] The battery cell provided in the embodiment of the present application can directly cool down or heat up the inside of the core by arranging a cold plate inside the core, and the cold plate accommodates a heat exchange medium, thereby improving the heat exchange effect of the core. At the same time, the cold plate arranged inside the core can increase the curvature radius of the innermost layer of the core, thereby suppressing problems such as powder loss caused by long-term use of the core.

[0006] In one implementation manner, the cold plate further includes a support structure, which is disposed in the first cavity and abuts against two surfaces of the cold plate that are opposite to each other in a thickness direction, and a modulus of the support structure is less than or equal to a first threshold.

[0007] In the embodiment of the present application, a support structure is arranged inside the cold plate, so that the expansion force inside the winding core in the thickness direction can be transmitted to the support structure of the cold plate, thereby offsetting part of the expansion force and improving the cycle performance of the battery cell.

[0008] In one implementation, the plurality of support structures are distributed along the width direction of the cold plate, the first support structure and the second support structure are respectively one of the plurality of support structures, the two oppositely arranged surfaces of the cold plate along the length direction are respectively the first surface and the second surface, the first support structure is connected to the first surface and is not connected to the second surface, and the second support structure is connected to the second surface and is not connected to the first surface.

[0009] Through the staggered distribution of multiple supporting structures, the heat exchange medium can be distributed in a continuous S shape in the first cavity, which can make the heat dissipation inside the core more uniform and improve the cooling effect. At the same time, the dispersed layout of multiple supporting structures can also better absorb and balance the expansion force inside the core.

[0010] In one implementation manner, the support structure includes a second cavity inside, and the second cavity is used to accommodate air, phase change material or elastic material.

[0011] In the embodiment of the present application, the second cavity accommodates cold air flow or hot air flow to further improve the cooling effect of the cold plate on the battery cell; the second cavity can also accommodate phase change material to absorb the heat of the battery cell and improve the heat capacity of the entire cold plate; the second cavity can also accommodate elastic material so that the cold plate has a rebound function after deformation, which not only has a supporting effect but also can better absorb the expansion force of the core.

[0012] In one implementation manner, the support structure and two surfaces of the cold plate that are arranged opposite to each other in the thickness direction are not perpendicular.

[0013] The embodiment of the present application improves the elastic performance of the supporting structure by tilting the supporting structure, which can more effectively reduce the expansion force inside the winding core.

[0014] In one of the implementations, the first supporting structure and the second supporting structure are respectively one of the multiple supporting structures, the third surface is one of the two surfaces of the cold plate arranged opposite to each other along the width direction, the vertical distance from the first end of the first supporting structure to the third surface is smaller than the vertical distance from the second end of the first supporting structure to the third surface, and the vertical distance from the first end of the second supporting structure to the third surface is larger than the vertical distance from the second end of the second supporting structure to the third surface, wherein the first end of the first supporting structure and the first end of the second supporting structure are both abutted against the fourth surface, and the second end of the first supporting structure and the second end of the second supporting structure are both abutted against the fifth surface; the fourth surface and the fifth surface are two surfaces of the cold plate arranged opposite to each other along the thickness direction.

[0015] The embodiment of the present application avoids the problem of structural imbalance or uneven deformation easily caused by the support structures in the cold plate tilting in the same direction by arranging adjacent support structures in opposite inclination directions, thereby improving the stability of the support structure inside the cold plate and increasing the service life of the winding core.

[0016] In one implementation manner, the first supporting structure and the second supporting structure are two adjacent supporting structures.

[0017] In one implementation manner, two surfaces of the cold plate that are arranged opposite to each other in the width direction and two surfaces of the cold plate that are arranged opposite to each other in the thickness direction form an arc-shaped intersection.

[0018] The embodiment of the present application provides a chamfered structure at the corners of the cold plate to reduce problems such as powder loss and poor contact at the bending of the core, thereby improving the service life and safety performance of the battery cell.

[0019] In one of the implementations, the heat exchange medium is a cooling liquid, the cold plate includes a liquid inlet and a liquid outlet both connected to the first cavity, the liquid inlet and the liquid outlet of the cold plate are both arranged on one of the two surfaces of the cold plate that are opposite to each other along the length direction, or the liquid inlet and the liquid outlet of the cold plate are respectively arranged on the two surfaces of the cold plate that are opposite to each other along the length direction; the shell includes a liquid inlet and a liquid outlet, the liquid inlet of the shell is connected to the liquid inlet of the cold plate, and the liquid outlet of the shell is connected to the liquid outlet of the cold plate.

[0020] In one implementation, a plurality of the roll cores are arranged along the thickness direction of the roll cores, wherein the first cold plate and the second cold plate are two adjacent cold plates, respectively, the liquid inlet of the first cold plate is connected to the liquid inlet of the shell, the liquid outlet of the first cold plate is connected to the liquid inlet of the second cold plate, and the liquid outlet of the second cold plate is connected to the liquid outlet of the shell.

[0021] When the heat exchange medium in the embodiment of the present application is a cooling liquid, a liquid inlet and a liquid outlet are designed at corresponding positions of the cold plate and the shell, so that the cooling path is more reasonable and the cooling effect of the cold plate is improved.

[0022] In one implementation, the winding core further includes a positive electrode tab and a negative electrode tab, the positive electrode tab is connected to the positive electrode sheet, the negative electrode tab is connected to the negative electrode sheet, and the positive electrode tab and the negative electrode tab are close to the shell.

[0023] In one implementation, the battery cell further includes a positive electrode column and a negative electrode column, the positive electrode column and the negative electrode column are mounted on the shell, and the positive electrode column and the negative electrode column are electrically connected to the winding core;

[0024] The positive electrode column and the negative electrode column are installed on the same end surface of the shell along the length direction of the cold plate, and the liquid inlet and the liquid outlet of the cold plate are arranged on the same surface of the cold plate close to the end surface; or the positive electrode column and the negative electrode column are respectively installed on different end surfaces of the shell along the length direction of the cold plate, and the liquid inlet and the liquid outlet of the cold plate are respectively arranged on different surfaces of the cold plate.

[0025] In one implementation, the heat exchange medium is a phase change material.

[0026] In the embodiment of the present application, the internal cavity of the cold plate is filled with phase change material, thereby improving the heat exchange effect of the cold plate on the battery cell. The phase change material is sealed in the cold plate, and there is no need to open a liquid inlet and outlet on the cold plate and the shell, and no external pump is required to promote the flow, thereby reducing the complexity of the battery cell structure and making actual production and use easier to achieve.

[0027] In one implementation manner, the battery core further includes a buffer layer, the buffer layer is arranged between the cold plate and the winding core, and the buffer layer is a rubber or ceramic coating.

[0028] The battery cell provided in the embodiment of the present application can increase the curvature radius of the core and reduce the problem of powder falling on the inner diameter of the core by setting a buffer layer between the core and the cold plate.

[0029] In a second aspect, a battery pack is provided, comprising: one or more battery cells as described in the first aspect and any one of the implementations of the first aspect, one or more of the battery cells being connected in series or in parallel; a battery pack shell, in which one or more of the battery cells are accommodated; and a battery management system, which is connected to the battery cells and is used to control the charging and discharging of the battery cells or monitor the status of the battery cells.

[0030] In a third aspect, an electric vehicle is provided, comprising the battery pack and an on-vehicle load as described in the second aspect, wherein the battery pack is used to supply power to the on-vehicle load.

[0031] In a fourth aspect, an energy storage system is provided, comprising a plurality of battery packs and power converters as described in the second aspect, wherein the power converter is used to perform power conversion on the voltage output by the battery pack and output it to an external grid or an external load, and / or the power converter is used to perform power conversion on the voltage output by an external power source and output it to the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of an energy storage system provided in an embodiment of the present application.

[0033] Figure 2 It is a schematic diagram of a battery cell provided in an embodiment of the present application.

[0034] Figure 3 It is a schematic diagram of a winding core provided in an embodiment of the present application.

[0035] Figure 4 It is a cross-sectional schematic diagram of a winding core provided in an embodiment of the present application.

[0036] Figure 5 It is a schematic top view of a winding core provided in an embodiment of the present application.

[0037] Figure 6 It is a schematic top view of a winding core provided in an embodiment of the present application.

[0038] Reference numerals:

[0039] 1000-energy storage system; 100-battery pack; 200-power converter; 1-battery cell; 2-battery pack shell; 3-battery management system; 10-shell; 20-winding core; 30-cold plate; 201-first isolation membrane; 202-positive electrode plate; 203-negative electrode plate; 204-second isolation membrane; 31-first cavity; 32-support structure; 301-liquid inlet of cold plate; 302-liquid outlet of cold plate; 101-liquid inlet of shell; 102-liquid outlet of shell; 103-cover plate; 104-positive pole; 105-negative pole; 210-positive pole ear; 220-negative pole ear; 110-explosion-proof valve; 321-second cavity. DETAILED DESCRIPTION

[0040] The following explains the terms that may appear in the embodiments of the present application.

[0041] Phase change material: A material that changes state and provides latent heat without changing temperature. The process of changing physical properties is called phase change, and the phase change material will absorb or release a large amount of latent heat. In particular, latent heat refers to the specific energy that a substance absorbs or releases during a phase change without changing temperature. Phase change materials (PCMs) usually have high density, low vapor pressure and good thermal conductivity, which can absorb a large amount of heat during the phase change process, thereby achieving the effect of endothermic regulation. For example, when the temperature of a waxy substance exceeds its melting point, it will change from solid to liquid, absorbing heat from the surrounding environment and forming latent heat until it is completely melted. Similarly, when the temperature decreases, the phase change material will change from liquid to solid, releasing latent heat to increase the temperature of the surrounding environment, achieving the effect of cooling regulation. Phase change materials are widely used in energy-saving thermal management and temperature stabilization in the fields of construction, electronics, chemicals, energy, etc. due to their high density, long-lasting and stable energy storage characteristics and low space requirements.

[0042] The technical solution in this application will be described below in conjunction with the accompanying drawings.

[0043] The embodiments of the present application provide a battery cell, a battery pack, an electric vehicle and an energy storage system, which can improve the cooling effect of the battery cell and improve the safety of battery use.

[0044] Figure 1 It is a schematic diagram of an energy storage system 1000 provided in an embodiment of the present application. The energy storage system 1000 may include multiple battery packs 100 and a power converter 200. The power converter 200 is used to convert the voltage output by the battery pack 100 and output it to the power grid or external load, and / or the power converter 200 is used to convert the voltage output by the external power supply and output it to the battery pack 100. The energy storage system 1000 may be a charging pile, a site backup power supply, a mobile base station power supply, etc., and may also be an energy storage system 1000 in scenarios such as household energy storage, industrial and commercial energy storage, and distributed energy storage, which is not limited in the present application.

[0045] The battery pack 100 described above may include one or more battery cells 1, and the multiple battery cells 1 may be connected in series or in parallel. For example, the poles of the battery cells 1 may be connected via a bus, so that the multiple battery cells 1 are connected in series or in parallel. The material of the bus may be a conductive metal material, such as aluminum Al. The battery pack 100 may also include a battery pack housing 2, and one or more battery cells 1 may be accommodated in the battery pack housing 2. The battery pack 100 may also include components such as a battery management system 3, which is connected to the battery cells 1, and the battery management system 3 is used to control and monitor the parameters of the battery cells and maintain the performance and safety of the battery cells.

[0046] Figure 2 1 is a schematic diagram of a battery cell 1 provided in the present application, and the battery cell 1 comprises: a shell 10, a winding core 20 and a cold plate 30, wherein the shell 10 is used to prevent the electrolyte from leaking to the outside of the battery cell 1, and the shell 10 is also used to fix the position of the winding core 20. A storage cavity is formed inside the shell 10, and the winding core 20 is placed in the storage cavity, and the cold plate 30 is used to perform heat exchange with the winding core 20.

[0047] Specifically, Figure 3 and Figure 4 As shown, the winding core 20 includes a positive electrode sheet 202, a first separator 201, a negative electrode sheet 203 and a second separator 204. The positive electrode sheet 202, the first separator 201, the negative electrode sheet 203 and the second separator 204 are sequentially stacked and wound along the outer surface of the cold plate 30, wherein the second separator is close to the outer surface of the cold plate. The cold plate 30 is a shell 10 structure with a hollow interior, such as Figure 5 As shown in (a) and (b), the cold plate 30 includes a first cavity 31 inside, and the first cavity 31 contains a heat exchange medium, such as a coolant or a phase change material.

[0048] It should be noted that the winding process of the winding core 20 is generally to first use two winding needles to clamp two layers of separators for pre-winding, and then sequentially feed the positive electrode sheet 202 or the negative electrode sheet 203, and the electrode sheets are respectively clamped between the two layers of separators 204 for winding. In the length direction of the winding core 20, the separator exceeds the negative electrode sheet 203, and the negative electrode sheet 203 exceeds the positive electrode sheet 202, so as to prevent the positive and negative electrode sheets from contacting and short-circuiting.

[0049] The battery cell provided in the embodiment of the present application can directly cool down or heat up the inside of the core by arranging a cold plate inside the core, and the cold plate accommodates a heat exchange medium, thereby improving the heat exchange effect of the core. At the same time, the cold plate arranged inside the core can increase the curvature radius of the innermost layer of the core, thereby suppressing problems such as powder loss caused by long-term use of the core.

[0050] In some embodiments, the positive electrode sheet 202 and the negative electrode sheet 203 of the winding core 20 can be wound based on the existing cold plate 30, or the positive electrode sheet 202 and the negative electrode sheet 203 of the winding core 20 can be wound with reserved space, and then the cold plate 30 is embedded. This embodiment of the application does not make specific limitations on this.

[0051] In some embodiments, Figure 4 As shown, the four corners formed by the surface along the width direction and the surface along the thickness direction of the cold plate can be right angles, and the winding corners of the winding core match the corners of the cold plate. However, in this case, when the battery cell 1 is charged and discharged, the thickness of the battery cell 1 caused by the expansion of the pole piece expands greatly, and the battery cell 1 is very easy to deform, resulting in poor interface contact, especially at the bend, which is prone to powder loss and overcharge lithium precipitation, which not only affects the cycle life, but also poses a safety hazard. Therefore, in some embodiments, Figure 3 As shown, the four corners formed by the surface along the width direction and the surface along the thickness direction of the cold plate can be chamfered. The chamfering is used to bevel or trim the four corners when the cold plate is formed, so that the surface along the width direction and the surface along the thickness direction of the cold plate form an arc intersection. The curvature of the corners of the cold plate 30 is matched with the winding corner of the core 20, which can reduce the occurrence of problems such as powder loss and poor contact at the bending of the core, thereby improving the service life and safety performance of the battery cell.

[0052] Lithium-ion and sodium-ion batteries will undergo reversible or irreversible volume expansion during the continuous charge and discharge process. Especially at the end of the battery life, the expansion force accumulated inside the battery cell 1 will not only reduce the activity of the positive and negative electrode materials, thereby affecting the battery performance, but will also cause damage to the battery module, battery pack 100 and other structures, increasing the cost of structural parts. In some embodiments, the cold plate 30 is a harmonica tube structure, that is, the cold plate 30 also includes one or more support structures 32, and the support structure 32 is placed in the first cavity 31 to absorb the expansion force inside the winding core 20. Figure 4As shown, the support structure 32 provides support in the thickness direction of the cold plate 30 , that is, the support structure 32 abuts against two inner surfaces of the cold plate 30 along the thickness direction, and the modulus of the support structure 32 is less than or equal to the first threshold.

[0053] Modulus is a mechanical property that measures the stiffness and deformation resistance of the support structure when subjected to force. The larger the value of the modulus, the more difficult it is for the support structure 32 to deform. Therefore, when the modulus of the support structure 32 is less than or equal to the first threshold, the support structure has appropriate elastic deformation capacity, and the expansion force accumulated inside the battery cell can be absorbed by the deformation of the support structure. Exemplarily, the support structure is made of aluminum, and the range of the first threshold can be 68GPa-80GPa. The first threshold can be set according to actual needs, and this application does not make specific limitations on this.

[0054] In the embodiment of the present application, a support structure 32 is provided inside the cold plate 30 , so that the expansion force inside the winding core 20 in the thickness direction can be transmitted to the support structure 32 of the cold plate 30 , thereby offsetting part of the expansion force and improving the cycle performance of the battery cell 1 .

[0055] In some embodiments, the battery cell also includes a buffer layer, which is disposed between the cold plate and the winding core to provide buffering and insulation between the cold plate and the winding core. Specifically, the buffer layer has a certain thickness, which is less than or equal to the second threshold value. Exemplarily, the second threshold value ranges from 100μm to 500μm. On the one hand, the buffer layer can have a certain buffer thickness between the cold plate and the battery cell, further increasing the radius of curvature of the innermost layer of the winding core and reducing the problem of powder loss on the inner diameter of the winding core. On the other hand, the thickness of the buffer layer does not exceed the second threshold value, which avoids the effect of excessive thickness on the heat exchange effect between the cold plate and the winding core. Specifically, the buffer layer also has insulating properties, and the resistivity of the buffer layer is within a first range. Exemplarily, the first range is 10 12 -10 1 6 ohm·m. For the second threshold value and the first range, those skilled in the art may select them according to actual needs, and the embodiments of the present application are not limited thereto.

[0056] In some embodiments, the buffer layer is a material or coating with insulating properties and certain thermal conductivity, such as rubber, polyphenylene ether insulation material, alumina ceramic coating or silicone, which is not specifically limited in the embodiments of the present application.

[0057] In some embodiments, the housing 10 is made of a material with good thermal conductivity, such as aluminum-plastic film, stainless steel, aluminum or steel, etc., which has an auxiliary effect on accelerating heat dissipation. The support structure 32 is made of elastic thermal conductive material, such as metal materials such as aluminum, nickel, stainless steel, silicone or polysiloxane materials, etc., but the embodiments of the present application are not limited thereto.

[0058] In some embodiments, Figure 4As shown, the support structure 32 can be inclined relative to the two inner surfaces of the cold plate 30 along the thickness direction, that is, it is not perpendicular to the two inner surfaces mentioned above. The inclined support structure can disperse the load to a larger area and reduce the impact of single-point concentrated load. This is conducive to reducing local stress concentration, improving the overall elastic performance of the structure, and enabling the expansion force inside the core to be offset by the extrusion deformation of the support structure, effectively reducing the internal expansion force.

[0059] In some embodiments, the inclination directions of two adjacent support structures 32 are inconsistent. Specifically, the first support structure and the second support structure are respectively one of the multiple support structures 32. The third surface is one of the two surfaces of the cold plate 30 that are arranged oppositely along the width direction. The vertical distance from the first end of the first support structure to the third surface is less than the vertical distance from the second end of the first support structure to the third surface. The vertical distance from the first end of the second support structure to the third surface is greater than the vertical distance from the second end of the second support structure to the third surface. The first end of the first support structure and the first end of the second support structure are both in contact with the fourth surface on the same surface of the cold plate, and the second end of the first support structure and the second end of the second support structure are both in contact with the fifth surface. The fourth surface and the fifth surface of the cold plate 30 are two surfaces that are arranged oppositely along the thickness direction of the cold plate. The first support structure and the second support structure can be two adjacent support structures. The two adjacent support structures 32 are arranged oppositely along the width direction of the cold plate 30, which can avoid the problem of structural imbalance or uneven deformation that is easily caused by the support structure in the cold plate tilting in the same direction, improve the stability of the support structure inside the cold plate, and increase the service life of the core.

[0060] In some embodiments, a plurality of support structures 32 are evenly distributed in the first cavity 31, so that the heat exchange medium contained in the first cavity 31 can also be evenly distributed, thereby evenly dissipating heat inside the core 20. Exemplarily, a plurality of support structures 32 are evenly and spaced apart along the width direction of the cold plate 30, and two adjacent support structures 32 are respectively connected to two different inner surfaces of the cold plate 30 along the length direction. For example, the first support structure 32 and the second support structure 32 are two adjacent support structures 32, one end of the first support structure 32 is connected to the first surface, and the other end is not connected to the second surface, one end of the second support structure 32 is connected to the second surface, and the other end is not connected to the first surface, that is, the first support structure 32 and the second support structure 32 are staggeredly distributed, wherein the first surface and the second surface are the two inner surfaces of the cold plate 30 along the length direction. Specifically, as Figure 5As shown in (b), through the staggered distribution of multiple support structures 32, the heat exchange medium can be distributed in a continuous S shape in the first cavity 31, which can make the heat dissipation inside the core 20 more uniform and improve the cooling effect. At the same time, the dispersed layout of the multiple support structures 32 can also better absorb and balance the expansion force inside the core 20. In some embodiments, Figure 6 As shown, the support structure 32 can be distributed in a U-shaped manner in the cold plate, so that the first cavity forms a U-shaped channel, and the heat exchange medium is distributed in a U-shaped manner in the first cavity, which can make the heat dissipation inside the core more uniform. The shape of the support structure and the first cavity of the embodiment of the present application is not limited to this.

[0061] In some embodiments, the support structure 32 includes a second cavity 321 inside, and the second cavity 321 is used to accommodate air or other media. For example, a second cavity 321 is formed inside each support structure 32; or each support structure 32 and the two inner surfaces along the thickness direction and the first surface of the cold plate 30 together form a second cavity 321. Exemplarily, the support structure 32 is a U-shaped plate structure, the support structure 32 is connected to the two inner surfaces along the thickness direction of the cold plate 30, and one side of the opening of the support structure 32 is connected to an inner surface of the cold plate 30 along the length direction, so that a U-shaped cavity is formed inside the support structure 32, and the U-shaped cavity is the second cavity.

[0062] In some embodiments, a ventilation pipe opening is provided at a position corresponding to the second cavity 321 of the cold plate 30. The second cavity 321 can accommodate cooling airflow and flow therein, thereby further improving the cooling effect of the cold plate 30 on the battery cell 1. The second cavity 321 can also accommodate phase change material to absorb the heat of the battery cell 1 and improve the heat capacity of the entire cold plate 30. The second cavity 321 can also accommodate elastic material, so that the cold plate 30 has a rebound function after deformation, which not only has a supporting function, but also can better absorb the expansion force of the core 20.

[0063] In some embodiments, the heat exchange medium in the first cavity 31 is a cooling liquid, and the cold plate 30 is provided with a liquid inlet 301 and a liquid outlet 302 on the surface along the length direction, and the liquid inlet 301 and the liquid outlet 302 of the cold plate are connected with the first cavity 31. On the surface of the shell 10 along the length direction of the cold plate 30, the shell 10 is provided with a liquid inlet 101 and a liquid outlet 102 corresponding to the liquid inlet 301 and the liquid outlet 302 of the cold plate. Optionally, the battery cell 1 may further include a pipeline, and the liquid inlet 101 of the shell is connected with the liquid inlet 301 of the cold plate through the pipeline, and the liquid outlet 102 of the shell is connected with the liquid outlet 302 of the cold plate through the pipeline, so that the cooling liquid flows from the liquid inlet 101 of the shell into the liquid inlet 301 of the cold plate, flows in the first cavity 31 through the action of an external pump, and then flows out from the liquid outlet 302 of the cold plate to the liquid outlet 102 of the shell, completing the process of cooling the inside of the core 20.

[0064] In some embodiments, a plurality of cores 20 are stacked and accommodated in the shell 10 along the thickness direction of the cores, and the liquid outlet and liquid inlet of each core 20 are connected in series. Specifically, the first core, the second core, and the third core are stacked and accommodated in the shell 10 in sequence along the thickness direction of the cores, the liquid inlet 301 of the first cold plate in the first core 20 is connected to the liquid inlet 101 of the shell, the liquid outlet 302 of the first cold plate is connected to the liquid inlet 301 of the second cold plate in the second core 20, the liquid outlet 302 of the second cold plate is connected to the liquid inlet 301 of the third cold plate in the third core 20, the liquid outlet 302 of the third cold plate is connected to the liquid outlet 102 of the shell, and the coolant flows from the shell 10 into the first cold plate, the second cold plate, and the third cold plate in sequence, and flows out of the shell 10.

[0065] In some embodiments, Figure 2 As shown, the shell 10 further includes a cover plate 103, and the battery cell 1 further includes a positive electrode column 104 and a negative electrode column 105. The positive electrode column 104 and the negative electrode column 105 are mounted on the cover plate 103 of the shell 10. The positive electrode column 104 is connected to the positive electrode sheet 202 of the winding core 20 through the positive electrode tab 210, and the negative electrode column 105 is connected to the negative electrode sheet 203 of the winding core 20 through the negative electrode tab 220. As shown in the figure, for the battery cell 1 with the positive electrode column 104 and the negative electrode column 105 on the same end face, the liquid outlet 302 and the liquid inlet of the cold plate can be set on the same end face; or, as shown in the figure, for example, the positive electrode column 104 and the negative electrode column 105 of the blade battery are respectively on two opposite end faces, and the liquid outlet 302 and the liquid inlet of the cold plate can also be respectively on two opposite end faces. The positions of the liquid inlet 301 and the liquid outlet of the cold plate are designed to correspond to the positions of the positive and negative poles 105 installed on the shell 10, which can facilitate the design of the shell 10. When multiple battery cells 1 are arranged in the battery pack 100, it can also facilitate the layout and convergence of the cooling liquid connection pipes.

[0066] In some embodiments, the material of the tab and the pole piece may be a conductive metal material. For example, the material of the positive pole piece 202 may be aluminum Al, such as aluminum foil, and the material of the negative pole piece 203 may be aluminum Al or copper Cu. The material of the positive tab 210 may be the same as that of the positive pole piece 202, and the material of the negative tab 220 may be the same as that of the negative pole piece 203. The material of the isolation film 204 may be polypropylene (PP) or polyethylene (PE), etc., which is not limited in the present application.

[0067] In some embodiments, the coolant uses a non-conductive working fluid that does not react violently with the electrolyte, such as mineral oil, fluorinated liquid, etc., which can effectively avoid the risk of leakage of the coolant inside the battery cell 1, but the embodiments of the present application are not limited to this.

[0068] In some embodiments, the heat exchange medium in the first cavity 31 is a phase change material, and the phase change material is encapsulated in the first cavity 31. Optionally, the phase change material can be a solid-to-liquid phase change material or a solid-to-gas phase change material. It should be noted that the phase change material reaches the phase change temperature point and undergoes enthalpy change, which is related to the selected phase change material. Exemplarily, the phase change material can be a low-temperature metal phase change material such as a bismuth alloy or other alloy metal. The low-temperature metal phase change material can be a liquid metal. The low-temperature metal phase change material has better thermal conductivity and lower electrical impedance among phase change materials, which can effectively promote heat transfer and reduce the temperature inside the core 20, but the embodiments of the present application are not limited to this.

[0069] In the embodiment of the present application, the internal cavity of the cold plate is filled with phase change material, thereby improving the cooling effect of the cold plate on the battery cell. The phase change material is sealed in the cold plate, and there is no need to open a liquid inlet and outlet on the cold plate and the shell, and no external pump is required to promote the flow, thereby reducing the complexity of the battery cell structure and making actual production and use easier to achieve.

[0070] In some embodiments, the battery cell 1 also includes a positive electrode connecting plate and a negative electrode connecting plate. The positive electrode connecting plate is arranged between the positive electrode column 104 and the positive electrode tab 210, and is used to connect the positive electrode column 104 and the positive electrode tab 210; the negative electrode connecting plate is arranged between the negative electrode column 105 and the negative electrode tab 220, and is used to connect the negative electrode column 105 and the negative electrode tab 220.

[0071] In some embodiments, the battery cell 1 further includes an explosion-proof valve 110 , which is disposed on the cover plate 103 of the shell 10 and between the positive and negative poles 105 , and is used for proper pressure release and heat dissipation to prevent explosion, leakage or overheating of the battery.

[0072] In some embodiments, the battery cell 1 may be a sodium ion battery cell or a lithium ion battery cell, or may also be a magnesium ion battery cell, a potassium ion battery cell, etc. The battery cell 1 may be a square battery cell or a soft pack battery cell.

[0073] The embodiment of the present application also provides an electric vehicle, which includes the battery pack described above, and a vehicle load, and the battery pack can be used to power the vehicle load. The electric vehicle can be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, and the vehicle load can include in-vehicle air conditioning equipment, lights, speakers, and other equipment, which are not limited in the present application.

[0074] It should be noted that the electric vehicle described above is only an example of an application scenario of the battery cells and battery packs described in this application. The battery cells and battery packs provided in this application can also be applied to other electrical equipment, such as ship equipment, aerospace equipment, etc.

[0075] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0076] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0077] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0078] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. Specifically, the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0079] The term "plurality" used in the present application refers to two or more (including two).

[0080] In the embodiments of the present application, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and subsequent associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0081] It should be noted that in the embodiments of the present application, the terms "upper", "lower", "vertical", "horizontal", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0082] The limitations such as symmetry (e.g., axisymmetry, or center symmetry, etc.) and sameness (e.g., same length, same width, etc.) mentioned in the embodiments of the present application are all for the current technological level, rather than being absolutely strict definitions in a mathematical sense. There may be a deviation of a predetermined threshold or a predetermined angle between the two.

[0083] Specifically, in various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0084] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A battery cell, characterized in that: It includes a shell, a winding core and a cold plate, wherein the winding core and the cold plate are accommodated in the shell; The winding core comprises a positive electrode sheet, a first separator, a negative electrode sheet and a second separator which are stacked in sequence, the winding core is wound along the outer surface of the cold plate, and the cold plate is located on a side of the second separator away from the negative electrode sheet; The cold plate is used for heat exchange with the winding core, and the cold plate includes a first cavity inside, and the first cavity is used for accommodating a heat exchange medium.

2. The battery cell according to claim 1, characterized in that: The cold plate further includes a support structure, which is disposed in the first cavity and abuts against two surfaces of the cold plate that are opposite to each other in a thickness direction, and a modulus of the support structure is less than or equal to a first threshold.

3. The battery cell according to claim 2, characterized in that: A plurality of support structures are distributed along the width direction of the cold plate, the first support structure and the second support structure are respectively one of the plurality of support structures, and two oppositely disposed surfaces of the cold plate along the length direction are respectively the first surface and the second surface, The first supporting structure is connected to the first surface and is not connected to the second surface, The second supporting structure is connected to the second surface and is not connected to the first surface.

4. The battery cell according to claim 2, characterized in that: A second cavity is formed inside the supporting structure, and the second cavity is used to contain air, phase change material or elastic material.

5. The battery cell according to claim 2, characterized in that: Two surfaces of the support structure and the cold plate that are arranged opposite to each other in the thickness direction are not perpendicular.

6. The battery cell according to claim 2, characterized in that: The first supporting structure and the second supporting structure are respectively one of the plurality of supporting structures, and the third surface is one of two surfaces of the cold plate that are oppositely arranged along the width direction. A vertical distance from the first end of the first supporting structure to the third surface is smaller than a vertical distance from the second end of the first supporting structure to the third surface. A vertical distance from the first end of the second supporting structure to the third surface is greater than a vertical distance from the second end of the second supporting structure to the third surface. Among them, the first end of the first supporting structure and the first end of the second supporting structure are both abutted against the fourth surface, and the second end of the first supporting structure and the second end of the second supporting structure are both abutted against the fifth surface; the fourth surface and the fifth surface are two surfaces of the cold plate arranged opposite to each other along the thickness direction.

7. The battery cell according to claim 3 or 6, characterized in that: The first supporting structure and the second supporting structure are two adjacent supporting structures.

8. The battery cell according to claim 1, characterized in that: Two surfaces of the cold plate that are opposite to each other in the width direction respectively intersect with two surfaces of the cold plate that are opposite to each other in the thickness direction to form an arc shape.

9. The battery cell according to claim 1, characterized in that: The heat exchange medium is a cooling liquid, the cold plate comprises a liquid inlet and a liquid outlet both connected to the first cavity, the liquid inlet and the liquid outlet of the cold plate are both arranged on one of two surfaces of the cold plate opposite to each other along the length direction, or the liquid inlet and the liquid outlet of the cold plate are respectively arranged on two surfaces of the cold plate opposite to each other along the length direction; The shell comprises a liquid inlet and a liquid outlet. The liquid inlet of the shell is communicated with the liquid inlet of the cold plate, and the liquid outlet of the shell is communicated with the liquid outlet of the cold plate.

10. The battery cell according to claim 1, characterized in that: The heat exchange medium is a phase change material.

11. The battery cell according to claim 1, characterized in that: The battery core further includes a buffer layer, which is arranged between the cold plate and the winding core, and the buffer layer is a rubber or ceramic coating.

12. A battery pack, characterized in that: include: One or more battery cells according to any one of claims 1 to 11, one or more of the battery cells being connected in series or in parallel; A battery pack housing, in which one or more of the battery cells are accommodated; A battery management system is connected to the battery cell, and is used to control the charging and discharging of the battery cell or monitor the status of the battery cell.

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