Battery cells and battery modules

Abstract

The present invention discloses a battery cell and a battery module. The battery cell includes: a shell, a cover plate, a winding core and a connector. The shell has an opening; the cover plate is arranged at the opening of the shell and forms a mounting cavity with the shell, and the mounting cavity has a cooling medium layer and an electrolytic medium layer arranged in layers; the winding core is accommodated in the working cavity and is at least partially arranged in the electrolytic medium layer; the connector is arranged in the mounting cavity, and one end is connected to the winding core and the other end extends toward the cover plate, and the connector is at least partially arranged in the cooling medium layer. When the battery cell is in use, the connector generates heat, and the cooling medium layer can quickly dissipate heat from the connector wrapped therein, thereby reducing the heat accumulation on the connector during high-current fast charging, thereby reducing the thermal safety risk of the battery cell caused by high temperature and increasing the practicality of the battery cell.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and in particular to a battery cell and a battery module. Background Art

[0002] Lithium-ion batteries are a high-tech product, a new type of high-capacity, long-life, environmentally friendly battery with excellent performance. Compared with nickel-cadmium and nickel-metal hydride batteries, lithium-ion batteries offer many advantages, including high voltage, high specific energy, long cycle life, excellent safety, minimal white discharge, no memory effect, fast charge and discharge, and a wide operating temperature range. Therefore, lithium-ion batteries are a high-quality power source for new energy electric vehicles.

[0003] Current lithium-ion batteries typically generate operating currents of several hundred amperes during charge and discharge. This significant Joule heat can cause the temperatures of connectors and the winding core to rise rapidly, even exceeding the battery's safe operating temperature or the trigger point for thermal runaway. During use, the winding core is often cooled by bottom-side liquid cooling, but the connectors are not effectively protected. Consequently, the connectors heat up further, potentially causing damage, ultimately directly impacting the battery pack's lifespan and safety. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is that in the prior art, since no cooling protection measures are taken at the connector, the connector is heated during use and is damaged.

[0005] To this end, the present invention provides a battery cell, comprising:

[0006] a housing having an opening;

[0007] a cover plate, the cover plate being arranged at the opening of the housing and forming a mounting cavity with the housing, wherein the mounting cavity has a cooling medium layer and an electrolytic medium layer arranged in layers;

[0008] a winding core, the winding core being disposed in the mounting cavity and at least partially disposed in the electrolyte layer;

[0009] A connecting member is provided in the installation cavity, one end of the connecting member is connected to the winding core, and the other end extends toward the cover plate. The connecting member is at least partially provided in the cooling medium layer.

[0010] Optionally, the above-mentioned battery cell,

[0011] The winding core is located in the electrolytic medium layer, the connecting member is located in the cooling medium layer, and the connection between the connecting member and the winding core is located at the boundary between the cooling medium layer and the electrolytic medium layer.

[0012] Optionally, the above-mentioned battery cell,

[0013] A heat-conducting layer is further provided in the installation cavity. The heat-conducting layer is provided on a side of the cooling medium layer away from the electrolytic medium layer and is layered with the cooling medium layer.

[0014] Optionally, the above-mentioned battery cell,

[0015] The electrolytic medium layer is arranged at the bottom of the installation cavity and is far away from the opening. The cooling medium layer is arranged at the top of the installation cavity and is close to the opening.

[0016] Optionally, the above-mentioned battery cell,

[0017] The invention also includes a partition plate, which is arranged in the installation cavity and separates the space of the installation cavity into a cooling cavity and a working cavity. The cooling cavity accommodates the cooling medium layer, and the working cavity accommodates the electrolytic medium layer.

[0018] Optionally, the above-mentioned battery cell,

[0019] The battery core further includes a conductive member, which is embedded in the partition, and the connecting member is connected to the winding core through the conductive member.

[0020] Optionally, the above-mentioned battery cell,

[0021] Also includes:

[0022] A first liquid injection part is provided on the cover plate, wherein the first liquid injection part has a first liquid injection channel, and the cooling cavity is connected to the outside through the first liquid injection channel; and / or

[0023] The second liquid injection piece is arranged on the cover plate and is spaced apart from the first liquid injection piece. The second liquid injection piece has a second liquid injection channel, and the working cavity is connected to the outside through the second liquid injection channel.

[0024] Optionally, the above-mentioned battery cell,

[0025] The battery cell includes a pole arranged on the cover plate;

[0026] The connecting member includes a first connecting segment connected to the pole, a second connecting segment bent and connected to one end of the first connecting segment, and a third connecting segment bent and connected to one end of the second connecting segment away from the first connecting segment, and the third connecting segment is connected to the winding core.

[0027] Optionally, the above-mentioned battery cell,

[0028] The second connecting segment is arranged perpendicular to the first connecting segment and the third connecting segment, and an extending direction of the third connecting segment is opposite to an extending direction of the first connecting segment.

[0029] A battery module includes the above-mentioned battery cell.

[0030] The technical solution provided by the present invention has the following advantages:

[0031] 1. The battery cell provided by the present invention comprises: a shell, a cover plate, a winding core, and a connector. The shell has an opening; the cover plate is arranged at the opening of the shell and forms a mounting cavity with the shell, the mounting cavity comprising a cooling medium layer and an electrolytic medium layer arranged in layers, the cooling medium layer and the electrolytic medium layer not being mixed with each other; the winding core is arranged in the mounting cavity and correspondingly arranged in the electrolytic medium layer and immersed in the electrolytic medium layer; the connector is arranged in the mounting cavity, with one end connected to the winding core and the other end extending toward the cover plate, the connector correspondingly arranged in the cooling medium layer and immersed in the cooling medium layer.

[0032] For battery cells of this structure, when the battery cells are in use, the connectors generate heat. At this time, since the connectors are immersed in the cooling medium layer, the heat generated by the connectors can be conducted by the cooling medium and then dissipated out of the shell, so that the cooling medium layer can quickly dissipate heat from the connectors wrapped by it, thereby reducing the heat accumulation on the connectors during high-current fast charging, thereby reducing the thermal safety risk of the battery cells caused by high temperature and increasing the practicality of the battery cells.

[0033] 2. The battery cell provided by the present invention further includes a partition. The partition is disposed in the mounting cavity and separates the mounting cavity into a cooling cavity and a working cavity. The cooling cavity accommodates the cooling medium layer, and the working cavity accommodates the electrolytic medium layer.

[0034] The battery cell of this structure divides the installation cavity into a cooling cavity and a working cavity by using a partition, so that the cooling medium layer and the electrolytic medium layer are separated under low temperature or normal temperature conditions, thereby expanding the range of material selection for the cooling medium layer and the electrolytic medium layer, and increasing the practicality of the battery cell.

[0035] 3. The battery cell provided by the present invention has a heat-conducting layer provided in the mounting cavity. The heat-conducting layer is arranged on the side of the cooling medium layer away from the electrolytic medium layer, and is layered with the cooling medium layer.

[0036] For battery cells of this structure, when they are in a high-temperature environment, an endothermic reaction and a gas-generating reaction will occur due to the addition of a heat-conducting layer on the cooling medium layer. The endothermic reaction can reduce the temperature of the battery cell, avoiding or delaying thermal runaway of the battery cell; the gas-generating reaction can increase the internal pressure of the battery cell, accelerate the opening of the explosion-proof valve, and thereby speed up the heat dissipation of the battery cell, reduce the risk of battery cell explosion, and reduce the heat propagation temperature gradient between the thermal runaway battery cell and the surrounding battery cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 This is a schematic diagram of the structure of the battery cell provided by the present invention;

[0039] Figure 2 This is a schematic structural diagram of another embodiment of the battery cell provided by the present invention.

[0040] Description of reference numerals:

[0041] 11-housing; 12-cover plate; 13-cooling cavity; 14-working cavity; 15-first liquid injection part; 16-second liquid injection part; 17-cooling medium layer; 18-electrolytic medium layer;

[0042] 2- core;

[0043] 3-connecting piece; 31-first connecting section; 32-second connecting section; 33-third connecting section;

[0044] 4-partition;

[0045] 5-pole;

[0046] 61-protective film; 62-encapsulation film;

[0047] 7- Explosion-proof valve. DETAILED DESCRIPTION

[0048] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0049] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0050] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0051] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0052] Example 1

[0053] This embodiment provides a battery cell, such as Figure 1 As shown, it includes: a shell 11, a cover plate 12, a core 2, and a connector 3. The shell 11 has an opening; the cover plate 12 is arranged to cover the opening of the shell 11 and form an installation cavity with the shell 11, and the installation cavity has a layered cooling medium layer 17 and an electrolytic medium layer 18; the core 2 is arranged in the working cavity 14 and is at least partially arranged in the electrolytic medium layer 18; the connector 3 is arranged in the cooling cavity 13, with one end connected to the core 2 and the other end extending toward the cover plate 12, and the connector 3 is at least partially arranged in the cooling medium layer 17. For example, in this embodiment, the electrolytic medium layer 18 is arranged at the bottom of the installation cavity and away from the opening, and the cooling medium layer 17 is arranged at the top of the installation cavity and close to the opening. When selecting materials, a cooling medium layer 17 with a high thermal conductivity is selected. Therefore, the material of the cooling medium layer 17 can be selected as dimethyl silicone oil. Of course, in other optional embodiments, the material of the cooling medium layer 17 can also be electronic fluoride liquid. The cooling medium layer 17 selected in this embodiment has a large thermal conductivity coefficient, and its thermal conductivity is far superior to the gas environment wrapped around the connector 3 in conventional battery cell designs, thereby further reducing the thermal safety risk of the battery cell.

[0054] Specifically, in the present application, the core 2 and the connector 3 can be immersed in the electrolytic medium layer 18 and the cooling medium layer 17 respectively in the following ways. In one way, the core 2 is located in the electrolytic medium layer 18, the connector 3 is located in the cooling medium layer 17, and the connection between the connector 3 and the core 2 is located at the boundary between the cooling medium layer 17 and the electrolytic medium layer 18. In this way, the core 2 and the connector 3 can be just immersed in the electrolytic medium layer 18 and the cooling medium layer 17, so that the heat dissipation and cooling effect of the core 2 and the connector 3 is better. In another way, the core 2 can be partially higher than the liquid level of the electrolytic medium layer 18 and extend into the cooling medium layer 17, so as to be connected to the connector 3 in the cooling medium layer 17. In addition, part of the connector 3 can also be extended into the electrolytic medium layer 18, thereby connecting to the core 2 in the electrolytic medium layer 18.

[0055] like Figure 1 As shown, in the battery cell provided by this embodiment, when the electrolyte layer 18 is consumed, the liquid level of the cooling medium layer 17 drops, and the cooling medium layer 17 can also assist the winding core 2 in dissipating heat, further meeting the heat dissipation requirements of the battery cell.

[0056] The cooling medium used in this embodiment is non-toxic, non-corrosive, safe to use, and will not damage the battery cell structure. In this embodiment, under 30-minute fast charging and bottom liquid cooling conditions, when using the battery cell provided by this embodiment, the maximum temperature of connector 3 is reduced from 77°C without cooling medium to 52°C, achieving rapid cooling of the connector.

[0057] like Figure 1 As shown, the battery cell provided in this embodiment further includes a pole 5 provided on the cover plate 12; the connector 3 includes a first connecting section 31 connected to the pole 5, a second connecting section 32 bent and connected to one end of the first connecting section 31, and a third connecting section 33 bent and connected to the second connecting section 32 away from one end of the first connecting section 31, and the third connecting section 33 is connected to the winding core 2. For example, in this embodiment, the second connecting section 32 is arranged perpendicular to the first connecting section 31 and the third connecting section 33, and the extension direction of the third connecting section 33 is opposite to the extension direction of the first connecting section 31. Through such an arrangement, the expansion area of the connector 3 in the cooling medium layer 17 is wider, so that the first connecting section 31, the second connecting section 32 and the third connecting section 33 can all be fully cooled by the cooling medium layer 17, so that the heat dissipation performance of the connector 3 is more superior, and the practicality of the battery cell is improved.

[0058] like Figure 1As shown, the battery cell provided in this embodiment further includes a protective film 61 and an encapsulation film 62. The protective film 61 is adapted to cover the outer surfaces of the side walls and bottom of the winding core 2; the encapsulation film 62 is adapted to encapsulate the housing 11. For example, in this embodiment, the protective film 61 is a Mylar film, which separates the housing 11 from the winding core 2. The encapsulation film 62 protects the battery cell, preventing external factors from affecting its performance.

[0059] like Figure 1 As shown, the battery cell provided in this embodiment further includes an explosion-proof valve 7, which is fixedly connected to the cover plate 12. In this embodiment, a heat-conducting layer is further provided in the mounting cavity, and the heat-conducting layer is arranged on the side of the cooling medium layer 17 away from the electrolytic medium layer 18, and is layered with the cooling medium layer 17. The heat-conducting layer undergoes an endothermic reaction and a gas-generating reaction with the cooling medium layer at high temperature. The endothermic reaction can reduce the temperature of the battery cell, thereby avoiding or delaying the thermal runaway process of the battery cell; and the gas-generating reaction increases the internal pressure of the battery cell and accelerates the opening of the explosion-proof valve 7, thereby further accelerating the heat dissipation speed of the battery cell, reducing the risk of explosion, and reducing the heat propagation temperature gradient between the thermal runaway battery cell and the surrounding battery cells.

[0060] In another optional embodiment, in addition to the first injection piece 15, a second injection piece 16 is also provided on the cover plate 12. The second injection piece 16 is spaced apart from the first injection piece 15 and has a second injection channel through which the working cavity 14 communicates with the outside world. The second injection piece 16 is also tubular. During use, the first injection piece 15 is used to add the cooling medium layer 17, and the second injection piece 16 is used to add the electrolytic medium layer 18. Because both the cooling medium layer 17 and the electrolytic medium layer 18 can be added simultaneously, the practicality of the battery cell is improved.

[0061] Of course, there is also an embodiment in which a separate second liquid injection member 16 is provided. In this case, when the cooling medium layer 17 and the electrolytic medium layer 18 are injected into the working cavity 14, the density of the cooling medium layer 17 is selected to be lower than that of the electrolytic medium layer 18 and they are not miscible with each other. Therefore, the cooling medium layer 17 will float upward above the electrolytic medium layer 18 and always wrap around the connector 3, ensuring reliability during the heat dissipation process.

[0062] In the battery cell provided in this embodiment, when the battery cell is in use, the connector 3 generates heat, and the cooling medium layer 17 can quickly dissipate the heat from the connector 3 wrapped therearound, thereby reducing heat accumulation on the connector 3 during high-current fast charging, thereby reducing the thermal safety risk of the battery cell caused by high temperature and increasing the practicality of the battery cell.

[0063] Example 2

[0064] The battery cell provided in this embodiment is compared with the battery cell provided in Example 1. Figure 2 As shown, the difference is that it also includes a partition 4, which is arranged in the installation cavity to separate the cooling cavity 13 and the working cavity 14. The cooling cavity 13 accommodates the cooling medium layer 17, and the working cavity 14 accommodates the electrolytic medium layer 18. By providing the partition 4, the installation cavity is divided into the cooling cavity 13 and the working cavity 14, so that the cooling medium layer 17 and the electrolytic medium layer 18 do not contact each other, so that the range of materials for the cooling medium layer 17 and the electrolytic medium layer 18 is expanded. That is, the cooling medium layer 17 and the electrolytic medium layer 18 can be selected to be mutually soluble, or the cooling medium layer 17 and the electrolytic medium layer 18 can be selected to be immiscible; at the same time, there is no limit on the density of the cooling medium layer 17 and the density of the electrolytic medium layer 18, thereby increasing the practicality of the battery cell.

[0065] In this embodiment, the partition 4 is made of an insulating polymer material with a melting point less than 200°C. For example, it can be made of PP material. In other optional embodiments, the partition 4 can also be made of PC material. Of course, the partition 4 can also be made of PVC material.

[0066] like Figure 2 As shown, the device further includes a conductive member embedded in the partition 4, through which the connector 3 is connected to the winding core 2. The conductive member provides an electrical connection between the winding core 2 and the connector 3. The conductive member should be made of a metal with low resistivity. In this embodiment, the conductive member is made of copper. In other alternative embodiments, the conductive member can be made of aluminum.

[0067] like Figure 2 As shown, in the battery cell provided in this embodiment, the cover plate 12 is provided with both a first injection piece 15 and a second injection piece 16. The first injection piece 15 is in communication with the cooling cavity 13, and the second injection piece 16 is in communication with the working cavity 14. During use, the first injection piece 15 is used to add a cooling medium layer 17, and the second injection piece 16 is used to add an electrolytic medium layer 18. This battery cell structure prevents the cooling medium layer 17 and the electrolytic medium layer 18 from contacting each other, thereby expanding the range of materials available for the cooling medium layer 17 and the electrolytic medium layer 18 and increasing the practicality of the battery cell.

[0068] The battery cell provided in this embodiment has a usage environment of low temperature environment, normal temperature environment and high temperature environment.

[0069] When the temperature is at low temperature or normal temperature, the partition 4 separates the working cavity 14 and the cooling cavity 13, so that the cooling medium layer 17 is not in direct contact with the electrolytic medium layer 18, which can ensure that the cooling medium layer 17 always covers the surface of the connector 3. At this time, there is no restriction on the density of the cooling medium layer 17. At this time, a cooling medium layer 17 with a large thermal conductivity coefficient is selected to wrap the connector 3. Since the thermal conductivity is much better than that of gas, the wrapped connector 3 can quickly dissipate heat, reduce heat accumulation during high-current fast charging, and reduce thermal safety risks caused by high temperature.

[0070] When the temperature is in a high temperature environment, the partition 4 is structurally destroyed due to heat, causing the cooling cavity 13 and the working cavity 14 to interpenetrate. Therefore, the cooling medium layer 17 will be mixed with the electrolyte medium layer 18 under the action of gravity. At this time, the cooling medium layer 17 selected needs to have a density less than the density of the electrolyte medium layer 18 when selecting the material. At this time, the heat conductive layer will undergo an endothermic reaction and a gas-generating reaction with the cooling medium layer 17 at high temperature. The endothermic reaction can reduce the temperature of the battery cell, thereby avoiding or delaying the thermal runaway process of the battery cell; and the gas-generating reaction increases the pressure inside the battery cell and accelerates the opening of the explosion-proof valve 7, thereby further speeding up the heat dissipation of the battery cell, reducing the risk of explosion, and reducing the heat propagation temperature gradient between the thermal runaway battery cell and the surrounding battery cells.

[0071] The battery cell structure provided in this embodiment uses a partition 4 to separate the cooling cavity 13 and the working cavity 14. In addition to the first liquid injection piece 15 connecting the cooling cavity 13, a second liquid injection piece 16 is provided to connect the working cavity 14. This allows for the timely addition of corresponding cooling medium layers 17 and electrolytic medium layers 18 to both the cooling cavity 13 and the working cavity 14. Furthermore, the range of materials available for the cooling medium layers 17 and the electrolytic medium layers 18 is expanded, increasing the practicality of the battery cell.

[0072] Example 3

[0073] This embodiment provides a battery module, including the battery cell provided in embodiment 1 or embodiment 2.

[0074] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A battery cell, characterized in that: include: a housing (11), wherein the housing (11) has an opening; a cover plate (12), the cover plate (12) being arranged on the opening of the housing (11) and forming a mounting cavity with the housing (11), wherein the mounting cavity has a cooling medium layer (17) and an electrolytic medium layer (18) arranged in layers; A winding core (2), the winding core (2) being arranged in the installation cavity, and the winding core (2) being located in the electrolytic medium layer (18); A connecting member (3), the connecting member (3) being arranged in the installation cavity, with one end connected to the winding core (2), and the other end extending toward the cover plate (12) and connected to the pole (5), the connecting member (3) being located in the cooling medium layer (17), and the connection between the connecting member (3) and the winding core (2) being located at the boundary between the cooling medium layer (17) and the electrolytic medium layer (18); A protective film (61), the protective film (61) covering the outer surface of the side wall of the winding core (2) and the outer surface of the bottom surface of the winding core (2); The cooling medium layer (17) has a density lower than that of the electrolytic medium layer (18), and the cooling medium layer (17) and the electrolytic medium layer (18) are immiscible.

2. The battery cell according to claim 1, characterized in that A heat-conducting layer is also provided in the installation cavity. The heat-conducting layer is provided on a side of the cooling medium layer (17) away from the electrolytic medium layer (18) and is layered with the cooling medium layer (17).

3. The battery cell according to claim 1, characterized in that The electrolytic medium layer (18) is arranged at the bottom of the installation cavity and is far away from the opening, and the cooling medium layer (17) is arranged at the top of the installation cavity and is close to the opening.

4. The battery cell according to any one of claims 1 to 3, characterized in that: The invention also includes a partition (4), wherein the partition (4) is arranged in the installation cavity and separates the space of the installation cavity into a cooling cavity (13) and a working cavity (14), wherein the cooling cavity (13) accommodates the cooling medium layer (17), and the working cavity (14) accommodates the electrolytic medium layer (18).

5. The battery cell according to claim 4, characterized in that: The battery core further comprises a conductive member, which is embedded in the partition (4), and the connecting member (3) is connected to the winding core (2) via the conductive member.

6. The battery cell according to claim 4, characterized in that Also includes: A first liquid injection part (15) is arranged on the cover plate (12), wherein the first liquid injection part (15) has a first liquid injection channel, and the cooling cavity (13) is connected to the outside through the first liquid injection channel; A second liquid injection piece (16) is arranged on the cover plate (12) and is spaced apart from the first liquid injection piece (15). The second liquid injection piece (16) has a second liquid injection channel, and the working cavity (14) is connected to the outside through the second liquid injection channel.

7. The battery cell according to any one of claims 1 to 3, characterized in that: The battery core includes a pole (5) arranged on the cover plate (12); The connecting member (3) comprises a first connecting section (31) connected to the pole (5), a second connecting section (32) bent and connected to one end of the first connecting section (31), and a third connecting section (33) bent and connected to one end of the second connecting section (32) away from the first connecting section (31), wherein the third connecting section (33) is connected to the winding core (2).

8. The battery cell according to claim 7, characterized in that: The second connecting section (32) is arranged perpendicular to the first connecting section (31) and the third connecting section (33), and the extending direction of the third connecting section (33) is opposite to the extending direction of the first connecting section (31).

9. A battery module, characterized in that: The invention comprises the battery cell according to any one of claims 1 to 8.

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