Battery and battery pack

Abstract

The present invention is applicable to the technical field of battery heat dissipation, and provides a battery, including a shell and a battery cell assembly arranged in the shell, wherein a preset mass of insulating liquid is injected into the shell, and the liquid level of the preset mass of insulating liquid in the shell is lower than the height of the battery cell assembly, and the preset mass of the insulating liquid is in a predetermined ratio to the difference between the total calorific value of the battery and the heat required for the battery to rise from the initial temperature to the maximum design temperature. The present invention also provides a battery pack, including a tray, a high-voltage distribution box, a battery module and a sealing cover, the sealing cover is provided with a heat dissipation structure, and the battery module includes a plurality of the above-mentioned batteries. A battery and a battery pack provided by the present invention effectively reduce the amount of insulating liquid used, and utilize the phase change heat of the insulating liquid to reduce the temperature difference of the battery, improve the heat exchange capacity, and ensure the temperature uniformity of the battery under working conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery heat dissipation, and in particular relates to a battery and a battery pack. Background Art

[0002] With the increasing popularity of new energy vehicles, the requirements for the use of power batteries in new energy vehicles are becoming higher and higher. In particular, users' requirements for the mileage of new energy vehicles are constantly increasing, so the overall capacity of new energy vehicle battery packs needs to be continuously improved; for example, to increase the capacity of the battery, a large number of batteries are connected in series into battery packs, and then the battery packs are assembled into power battery packs; two adjacent batteries need to be connected by power connectors. Power connectors will increase the internal resistance of the battery, increase the internal consumption and heat generation of the power battery pack during use, and ensure the normal operation of the battery pack, avoid thermal runaway and fire and explosion, and improve safety. It is particularly urgent to study the thermal management technology of the battery pack and its implementation.

[0003] In the prior art, the battery pack is filled with insulating liquid, and the liquid that absorbs heat and heats up in the battery pack is transported to the outside of the battery pack through a pump, and the heat is dissipated through fin air cooling. Since the insulating liquid fills the battery pack shell, a large amount of insulating liquid is used, which is costly. In addition, when fin air cooling is used, the battery pack is large in size and has a non-compact structure. At the same time, under harsh conditions, when the battery generates a lot of heat, the fin air cooling heat exchange capacity is limited, and there may be insufficient heat dissipation capacity. When using insulating liquid cooling sensible heat to dissipate heat from the battery, when the battery pack is large in size, the temperature of the insulating liquid continues to rise as the pump works, and the heat exchange capacity decreases, resulting in a large temperature difference between the batteries. Summary of the invention

[0004] The present invention aims to solve at least one of the above-mentioned technical problems, and provides a battery and a battery pack, which effectively reduces the amount of insulating liquid used, and utilizes the insulating liquid phase change heat to reduce the battery temperature difference, improve the heat exchange capacity, and ensure the temperature uniformity when the battery is in working state.

[0005] The technical solution of the present invention is: a battery, comprising a shell and a battery cell assembly arranged in the shell, a preset mass of insulating liquid is injected into the shell, the liquid level of the preset mass of the insulating liquid in the shell is lower than the height of the battery cell assembly, and the preset mass of the insulating liquid is in a predetermined ratio to the difference between the total calorific value of the battery and the heat required for the battery to rise from an initial temperature to a maximum design temperature.

[0006] Optionally, the preset mass of the insulating liquid is according to the formula: To determine, where A is a predetermined constant, and A ≥ 1, C fluid is the specific heat capacity of the insulating liquid, T fluid-boiling is the boiling point of the insulating liquid, T0 is room temperature, Q batteryis the total heat generated by the battery, Q limit It is the heat required for the battery to rise from its initial temperature to the maximum design temperature.

[0007] Optionally, in the formula: In, 1.3>A≥1.

[0008] Optionally, a plurality of battery cell assemblies are provided, and two adjacent battery cell assemblies are electrically connected via a connecting structure. A partition is provided between two adjacent battery cell assemblies, and the partition is used to separate and fix the battery cell assemblies, and there is a gap between the partition and the shell.

[0009] Optionally, the shell includes an outer shell having an opening and a cover plate covering the opening, the battery cell assembly is loaded into the outer shell through the opening, and a receiving cavity for storing the insulating liquid is formed between the outer shell and the battery cell assembly.

[0010] Optionally, the cover plate is provided with a liquid injection hole for injecting the insulating liquid into the accommodating cavity.

[0011] Optionally, the liquid injection hole is located above the liquid level of the insulating liquid in the accommodating cavity.

[0012] Optionally, a pressure sensor is provided in the accommodating cavity, and the shell is provided with an explosion-proof structure.

[0013] The present invention also provides a battery pack, including a tray, a high-voltage distribution box, a battery module and a sealing cover, wherein the battery module is installed in the tray, the high-voltage distribution box is electrically connected to the battery module, the sealing cover is sealed on the top of the battery module and is fixed to the tray by a locking member, the sealing cover is provided with a heat dissipation structure, and the battery module includes several of the above-mentioned batteries.

[0014] Optionally, in the battery module, a plurality of the batteries are arranged along a set direction, and along the set direction, a liquid level of the insulating liquid in the battery close to the tray frame is lower than a liquid level of the insulating liquid in the battery close to the center of the tray.

[0015] Optionally, the heat dissipation structure is a liquid cooling plate and / or a fin structure.

[0016] The present invention provides a battery and a battery pack, wherein a preset mass of insulating liquid is injected into the battery shell, and the liquid level of the insulating liquid in the shell is lower than the height of the battery cell assembly, and the preset mass of the insulating liquid is further limited, so that the preset mass of the insulating liquid is in a predetermined ratio with the difference between the total heat generation of the battery and the heat required for the battery to rise from the initial temperature to the maximum design temperature, so as to ensure that the amount of insulating liquid is effectively reduced on the basis of being able to effectively dissipate heat for the battery, thereby reducing the cost of the insulating liquid, and utilizing the phase change heat of the insulating liquid to reduce the temperature difference of the battery; after the above-mentioned battery is made into a battery pack, a heat dissipation structure is provided on the top of the battery assembly, and the heat dissipation structure is utilized to accelerate the heat dissipation. At the same time, the part of the battery module in contact with the sealing cover dissipates heat faster and has a low temperature, and there will be a large heat transfer temperature difference in the vertical direction. The greater the heat transfer amount, the greater the temperature difference, and the faster the speed of the insulating liquid rising and flowing after vaporization, thereby accelerating the heat dissipation efficiency and ensuring the temperature uniformity of the battery pack under working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 is a schematic structural diagram of a battery provided by an embodiment of the present invention;

[0019] Figure 2 is an exploded schematic diagram of a battery provided by an embodiment of the present invention;

[0020] Figure 3 is a cross-sectional schematic diagram of a battery provided by an embodiment of the present invention;

[0021] Figure 4 is an exploded schematic diagram of a battery pack provided by an embodiment of the present invention;

[0022] Figure 5 yes Figure 4 A magnified schematic diagram of center A.

[0023] In the figure, 1-battery, 10-accommodating cavity, 11-first pole, 12-second pole, 13-explosion-proof structure, 2-shell, 21-cover plate, 22-shell, 221-opening, 3-cell assembly, 4-partition, 5-insulating liquid, 6-liquid injection hole, 7-insulating film, 100-tray, 101-high-voltage distribution box, 102-battery module, 103-sealing cover, 104-liquid cooling plate, 105-sealing structure, 106-insulation material. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0025] It should be noted that the terms "setting" and "connecting" should be understood in a broad sense. For example, it can be directly setting, installing, and connecting, or it can be indirectly setting and connecting through a central component or a central structure.

[0026] In addition, in the embodiments of the present invention, if there are orientations or positional relationships indicated by "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., they are based on the orientations or positional relationships shown in the drawings or the conventional placement state or use state, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the structure, feature, device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In the description of the present invention, unless otherwise specified, the meaning of "multiple" is two or more.

[0027] The various specific technical features and embodiments described in the specific implementation methods can be combined in any suitable manner unless there is any contradiction. For example, different implementation methods can be formed by combining different specific technical features / embodiments. In order to avoid unnecessary repetition, the various possible combinations of the specific technical features / embodiments in the present invention will not be described separately.

[0028] like Figures 1 to 3As shown, a battery 1 provided in an embodiment of the present invention comprises a housing 2 and a cell assembly 3 arranged in the housing 2. The cell assembly 3 in this embodiment is a complete soft-pack battery structure that can be used independently, comprising an aluminum-plastic film shell (or other materials), a positive electrode sheet, a diaphragm, a negative electrode sheet, and an electrolyte, etc. Its specific arrangement and connection relationship are the prior art. In order to improve the heat dissipation capacity of the battery 1, an insulating liquid 5 with a preset mass is injected into the housing 2, wherein the liquid level H1 of the insulating liquid 5 in the housing 2 is lower than the height H2 of the cell assembly 3, and the cell assembly 3 is immersed in the insulating liquid 5. The heat generated by the battery 1 during the charging and discharging process is absorbed by the insulating liquid 5, and the temperature of the insulating liquid 5 increases, so that the temperature of the battery 1 decreases. When the battery 1 generates a large amount of heat, the temperature of the insulating liquid 5 rises rapidly, and when the temperature of the insulating liquid 5 rises to its boiling point, the insulating liquid 5 evaporates and absorbs a large amount of heat to reduce the temperature of the battery 1, preventing the battery 1 from being overheated and easily causing thermal runaway. After the insulating liquid 5 vaporizes, it flows upward and contacts the top of the shell 2 to generate heat exchange. On the one hand, the heat can be discharged out of the shell 2, and at the same time, the insulating liquid 5 vapor condenses back into the insulating liquid 5 and falls back to the bottom of the shell 2. On the other hand, after the insulating liquid 5 vaporizes, it flows upward and transfers the heat to the top of the shell 2 to avoid a large temperature difference in the battery 1. Compared with the solution in the prior art that the battery cell assembly 3 is immersed in the insulating liquid 5 as a whole and the insulating liquid 5 fills the inside of the battery shell, the amount of insulating liquid 5 in the battery 1 provided in this embodiment is small, the cost of the insulating liquid 5 is reduced, and the insulating liquid 5 is used to heat the battery 10 by phase change.

[0029] In order to ensure that the insulating liquid 5 injected into the shell 2 can meet the heat dissipation requirements of the battery 1 without filling the entire shell 2, the purpose of reducing the amount of insulating liquid 5 is achieved. In the present invention, it is further defined that the preset mass of the insulating liquid 5 is in a predetermined ratio with the difference between the total calorific value of the battery 1 and the heat required for the battery 1 to rise from the initial temperature to the maximum design temperature. The total calorific value of the battery 1 refers to the total heat generated by the battery 1 during the process of charging and discharging according to the set current (for example: 0.5C operating condition charging or discharging, 1C operating condition charging or discharging, 2C operating condition charging or discharging, etc.) at normal temperature. The initial temperature refers to the temperature when the battery 1 starts to charge and discharge, generally refers to normal temperature (22℃±5℃). The maximum design temperature refers to the maximum operating temperature that the battery 1 needs to control during normal charging and discharging. According to the working environment requirements, for example, the maximum design temperature can be 32°, 35°, 38°, etc. If the temperature of the battery 1 exceeds the maximum design temperature, it will affect its life, performance, etc. At the same time, if the temperature of the battery 1 continues to rise, it is easy to cause thermal runaway, which poses a safety hazard. Therefore, it is necessary to remove excess heat (Q battery -Q limit ) to prevent the temperature of the battery 1 from exceeding the maximum design temperature during operation. battery is the total heat generated by battery 1, Q limitThe amount of heat required for the battery 1 to rise from the initial temperature to the maximum design temperature. Since the amount of heat absorbed by the insulating liquid 5 is determined by its mass, the amount of heat Q absorbed by the insulating liquid 5 injected into the housing 2 to completely vaporize the preset mass of the insulating liquid 5 is fluid =C fluid ·m fluid ·(T fluid-boiling -T0),m fluid is the mass of insulating liquid 5, C fluid is the specific heat capacity of the insulating liquid 5, T fluid-boiling is the boiling point of the insulating liquid 5, T0 is room temperature, if the material of the insulating liquid 5 has been determined, then C fluid ·(T fluid-boiling -T0) is a known quantity. The preset mass of the insulating liquid 5 Q fluid By (Q battery -Q limit ) to determine, under severe conditions, the amount of heat that the battery needs to dissipate (Q battery -Q limit ) is equal to the heat required to completely vaporize the preset mass of insulating liquid. Therefore, in an ideal state, Q fluid =Q battery -Q limit , Q limit Calculate according to the formula: Q limit =C battery ·M battery ·(T tmax -T0),C battery is the specific heat capacity of battery 1, M battery is the mass of battery 1, T tmax is the maximum design temperature. That is, the final formula is: To calculate the preset mass of the insulating liquid 5.

[0030] However, in order to avoid the insufficient mass of the injected insulating liquid 5 due to weighing error, or the loss of the insulating liquid 5 during evaporation, vaporization and condensation, resulting in insufficient mass of the insulating liquid 5 and inability to effectively dissipate heat, the preset mass of the insulating liquid 5 injected into the housing 2 is further limited to: Wherein, A is a predetermined constant, and A≥1.

[0031] In order to avoid the total heat of the battery Q battery Affected by the volume of shell 2, by further defining: Q battery ≤Q max , Q max Q is the heat required for the complete evaporation of the insulating liquid 5 when the battery 1 housing 2 is filled with the insulating liquid 5. max =C fluid ·mfluid-boiling ·(T fluid-boiling -T0), m fluid-boiling The mass of the insulating liquid 5 filled in the battery 1 shell 2 is ensured in this way to ensure that the design of the shell 2 meets the requirements and prevent the battery 1 heat dissipation requirements from being unable to be met even if the shell 2 is filled with insulating liquid 5 after the battery cell assembly 3 is installed in the shell 2 and the battery cell assembly 3 occupies a large amount of space inside the shell 2.

[0032] In order to ensure that the amount of insulating liquid 5 is reduced while effectively dissipating the heat of the battery, the value of A is further limited to: 1.3>A≥1.

[0033] Optionally, a plurality of battery cell assemblies 3 are provided, and two adjacent battery cell assemblies 3 are electrically connected via a connecting structure (not shown in the figure) to achieve electrical connection between adjacent battery cell assemblies 3. A partition 4 is provided between two adjacent battery cell assemblies 3, and the partition 4 is used to separate and fix the battery cell assemblies 3, so that the battery cell assemblies 3 do not contact each other and remain stationary relative to the shell 2, and there is a gap between the partition 4 and the shell 2, and the insulating liquid 5 can flow in the shell 2, so that the battery cell assemblies 3 are immersed in the insulating liquid 5.

[0034] Specifically, there is a gap between the partition 4 and the side wall of the outer shell 22, and the bottom of the partition 4 is fixedly connected to the bottom surface of the outer shell 22, ensuring the fixing effect of the battery cell assembly 3, preventing the battery cell assembly 3 from shaking in the accommodating cavity 10, and will not affect the circulation of the insulating liquid 5.

[0035] Specifically, the connection structure may be a connecting copper busbar.

[0036] Alternatively, if Figure 2 As shown, the shell 2 includes an outer shell 22 with an opening 221 and a cover plate 21 covering the opening 221. After a plurality of battery cell assemblies 3 are loaded into the outer shell 22 through the opening 221, a receiving cavity 10 for storing insulating liquid 5 is formed between the outer shell 22 and the battery cell assembly 3. The insulating liquid 5 can flow in the receiving cavity 10, so that each battery cell assembly 3 is immersed in the insulating liquid 5, thereby ensuring the heat dissipation effect of each battery cell assembly 3.

[0037] Specifically, the partition 4 may be an insulating heat-insulating plate to prevent heat from being transferred through the partition 4 and ensure that adjacent battery cell assemblies 3 are independent of each other.

[0038] Alternatively, if Figures 1 to 3 As shown, the cover plate 21 may be provided with a liquid injection hole 5, through which the insulating liquid 5 is injected into the accommodating cavity 10, and then the liquid injection hole 5 is sealed to prevent leakage of the insulating liquid 5. For example, the sealing may be performed by welding or using a rubber plug.

[0039] Furthermore, if Figure 3As shown, the injection hole 5 can be located above the liquid level of the insulating liquid 5 in the accommodating cavity 10, that is, the injection hole 5 is higher than the liquid level of the insulating liquid 5 in the accommodating cavity 10, so as to facilitate the injection of the insulating liquid 5 into the accommodating cavity 10. In practical applications, the injection hole 5 can also be located at other positions of the housing 2, as long as the injection hole 5 is higher than the liquid level of the insulating liquid 5 in the accommodating cavity 10.

[0040] Alternatively, if Figures 1 to 3 As shown, the battery 1 further includes a first pole 11 and a second pole 12. The first pole 11 is disposed on the cover plate 21, and the second pole 12 is disposed on the side of the housing 22 opposite to the cover plate 21. The first pole 11 and the second pole 12 have different polarities. For example, the first pole 11 is a positive pole, and the second pole 12 is a negative pole. In practical applications, the first pole 11 and the second pole 12 are respectively located at opposite ends of the cover plate 21.

[0041] Optionally, a pressure sensor (not shown in the figure) may be provided in the accommodating chamber 10. As the insulating liquid 5 evaporates and vaporizes, a large amount of gas is generated, causing the pressure in the accommodating chamber 10 to increase. The pressure sensor can be used as an early warning of thermal runaway of the battery 1. The shell 2 can be provided with an explosion-proof structure 13 for pressure relief to prevent the pressure in the accommodating chamber 10 from being too high.

[0042] In this embodiment, the explosion-proof structure 13 is disposed on the cover plate 21 , and the explosion-proof structure 13 is an explosion-proof valve.

[0043] Optionally, the insulating liquid 5 may be a non-corrosive substance with a boiling point of 25°C-50°C, which will not corrode the battery cell assembly 3 immersed in the insulating liquid 5 while ensuring the heat dissipation effect, such as fluorinated liquid. In practical applications, other non-toxic and environmentally friendly liquids can also be used as insulating liquids.

[0044] The present invention also provides a battery pack, such as Figure 4 and Figure 5As shown, it includes a tray 100, a high-voltage distribution box 101, a battery module 102 and a sealing cover 103. The battery module 102 is installed in the tray 100. For example, the bottom surface of the battery module 102 is fixedly connected to the tray 100 by structural adhesive, and screws can also be used to fix the battery module 102 to the tray 100. The high-voltage distribution box 101 is electrically connected to the battery module 102. The output port of the high-voltage distribution box 101 protrudes out of the tray 100. The sealing cover 103 is sealed on the top of the battery module 102 and fixed to the tray 100 by a locking member to ensure the stability of the installation of the battery module 102. The sealing cover 103 is provided with a heat dissipation structure. The battery module 102 includes a plurality of the above-mentioned batteries 1. The amount of insulating liquid 5 in the battery pack is reduced, and the production cost is effectively reduced. In the battery pack, by combining the insulating liquid 5 in the battery 1 and the heat dissipation structure on the top of the battery module 102, the heat dissipation efficiency is accelerated and the safety of the battery pack is improved. When the battery pack is working, the temperature of each battery 1 increases. According to the second law of thermodynamics, heat is transferred from the battery cell assembly 3 to the low-temperature insulating liquid 5, and the temperature of the insulating liquid 5 gradually increases. When the temperature of the insulating liquid 5 is higher than its boiling point, the insulating liquid 5 evaporates and vaporizes to form gas. The gas flows upward to the top of the shell 2 under the action of buoyancy. The heat carried by the gas is transferred to the sealing cover 103 to dissipate heat outward, and then the gas condenses back into the insulating liquid 5, and falls back to the bottom of the shell 2 under the action of gravity, absorbing heat and evaporating again, forming a cycle. Since the sealing cover 103 is provided with a heat dissipation structure, the heat dissipation is accelerated, so that there is a large heat transfer temperature difference in the vertical direction. When the heat transfer amount is greater, the temperature difference is greater, and the gas formed by the evaporation of the insulating liquid 5 flows faster in the vertical direction, thereby accelerating the heat dissipation efficiency, making the temperature difference of the battery module 102 smaller, and improving the temperature uniformity under the working state.

[0045] Optionally, the battery module 102 is obtained by arranging a plurality of batteries 1 along a set direction, where the set direction specifically refers to the length direction or width direction of the tray 100. Under the same charge and discharge conditions, the heat dissipation capabilities of the batteries 1 at different positions are different. For example, the heat dissipation of the battery 1 near the frame of the tray is stronger, while the heat dissipation capability of the battery 1 at the middle position is poorer, that is, the heat of two adjacent batteries 1 will interfere with each other, resulting in the heat dissipation capability of the battery 1 in the middle of the tray 100 being poorer. Therefore, in the battery module 102, the liquid level of the insulating liquid 5 in the battery 1 near the frame of the tray 100 along the set direction is lower than the liquid level of the insulating liquid 5 in the battery 1 near the center of the tray 11, that is, the mass of the insulating liquid 5 in the battery 1 near the center of the tray 11 is greater. In this way, along the set direction, the liquid level height H1 values ​​of the batteries 1 at different positions are different. Specifically, the farther the battery 1 in the battery module 102 is from the frame of the tray 100, the higher the liquid level of the internal insulating liquid 5. Through this differentiated design, the temperature difference of the battery pack can be further reduced and the uniformity of the battery pack temperature can be improved.

[0046] Alternatively, if Figure 2 As shown, the shell 2 of each battery 1 may be covered with an insulating film 7. By providing the insulating film 7, it is ensured that each battery 1 is independent of each other and does not interfere with each other.

[0047] Specifically, the insulating film 7 can be made of materials such as polyimide, polyethylene, polyvinylidene fluoride, and polytetrafluoroethylene. Furthermore, in order to protect the battery 1 and prevent external forces from damaging the battery 1 housing 2, the insulating film 7 can adopt a multi-layer composite film structure, for example, the inner layer is used as an insulating layer, the middle layer is used as a waterproof layer, and the outer layer is used as a protective layer. The inner layer includes a plastic material, for example, the inner layer can be made of a material that has less reactivity with the electrolyte in the isolation membrane and has insulating properties, such as polyethylene. The middle layer includes a metal material that can prevent water vapor from penetrating the outside of the battery 1. It is preferred to use aluminum foil, stainless steel foil, copper foil, etc. Considering the molding performance, light weight and cost, it is best to use aluminum foil. As the material of the aluminum foil, pure aluminum-based or aluminum-iron-based alloy materials are preferably used; the outer layer is a protective layer, and high-melting-point mantle or nylon materials are mostly used, which have strong mechanical properties, prevent external forces from damaging the battery 1, and play a role in protecting the battery 1.

[0048] Alternatively, if Figure 4 As shown, the heat dissipation structure may be a liquid cooling plate 104 or / and a fin structure. Specifically, the specific type of heat dissipation structure may be selected according to actual conditions. For example, for a battery pack without high heating conditions, the heat dissipation structure may be a fin structure formed on the surface of the sealing cover 103, and the heat absorbed by the evaporation of the insulating liquid 5 is dissipated by air cooling (natural cooling or forced air cooling), which not only ensures the heat dissipation effect but also reduces the heat dissipation cost; for a battery pack with high heating conditions, the heat dissipation structure may be a liquid cooling plate 104 integrated in the sealing cover 103, and the heat generated by the battery 1 and the heat absorbed by the evaporation of the insulating liquid 5 are released through the liquid cooling plate 104; for a battery pack with ultra-high heating conditions, the heat dissipation structure includes a liquid cooling plate 104 integrated in the sealing cover 103 and a fin structure formed on the surface of the sealing cover 103.

[0049] Furthermore, in the battery pack of the present invention, the heat dissipation structure is a liquid cooling plate 104 integrated in the sealing cover 103. In this way, the battery pack has two modes of passive heat exchange and active heat exchange. Under low-heat working conditions, the battery pack is cooled by passive heat exchange, that is, the temperature of the battery 1 is controlled and the temperature difference is reduced by the heating and evaporation of the insulating liquid 5. Specifically, the cell assembly 3 of the battery 1 generates heat, and the generated heat is absorbed by the insulating liquid 5, and the temperature of the battery 1 decreases. As the temperature of the insulating liquid 5 gradually increases, when the temperature of the insulating liquid 5 is higher than its boiling point, the insulating liquid 5 evaporates to form gas and flows upward under the action of buoyancy. After the gas formed by the evaporation of the insulating liquid 5 reaches the top of the shell 2, it transfers the heat to the liquid cooling plate 104, and then the gas formed by the evaporation of the insulating liquid 5 releases heat and condenses, turning back into the insulating liquid 5 and falling back to the bottom of the shell 2 under the action of gravity, absorbing heat and evaporating again, forming a cycle. Under high-heat conditions, the liquid cooling plate 104 actively dissipates heat, and coolant flows in the liquid cooling plate 104 to accelerate heat dissipation. Specifically, part of the heat generated by the battery 1 is directly transferred to the liquid cooling plate 104 through its own heat conduction, and the other part of the heat is absorbed by the insulating liquid 5, and the heat is transferred to the liquid cooling plate 104 through the phase change of the insulating liquid 5. The battery pack of the present invention can choose to adopt different thermal management strategies according to different heating conditions of the battery pack, that is, to determine whether the liquid cooling plate 104 needs to work, effectively reducing energy consumption.

[0050] Alternatively, if Figure 4 As shown, a sealing structure 105 may be provided between the sealing cover 103 and the tray 100, and the sealing cover 103 is fixedly connected to the tray 100 by bolts or screws. The sealing structure 105 may be a sealing rubber pad.

[0051] Alternatively, if Figure 4 As shown, the sealing cover 103 may be covered with a heat-insulating material 106 . By providing the heat-insulating material 106 , such as heat-insulating foam, the liquid cooling plate 104 may be prevented from exchanging heat with the environment, thereby reducing the heat dissipation capacity of the liquid cooling plate 104 for the battery module 102 .

[0052] Optionally, a heat-conducting material (not shown in the figure), such as a heat-conducting structural adhesive, is provided between the sealing cover 103 and the top of the battery module 102. The heat-conducting structural adhesive connects and fixes the sealing cover 103 to the top of the battery module 102. The heat-conducting structural adhesive also facilitates heat transfer, thereby further improving heat dissipation efficiency.

[0053] In a battery 1 and a battery pack provided by an embodiment of the present invention, a preset mass of insulating liquid 5 is injected into a shell 2 of the battery 1, and a liquid level height H1 of the insulating liquid 5 in the shell 2 is lower than a height H2 of a cell assembly 3, and the preset mass of the insulating liquid 5 is further limited, so that the preset mass of the insulating liquid 5 is in a predetermined ratio to the difference between the total heat generation of the battery 1 and the heat required for the battery 1 to rise from an initial temperature to a maximum design temperature, so as to effectively reduce the amount of the insulating liquid 5 on the basis of ensuring effective heat dissipation of the battery 1, thereby reducing the cost of the insulating liquid 5, and utilizing the insulating liquid 5. Phase change heat is transferred to reduce the temperature difference of the battery 1; after the above-mentioned battery 1 is made into a battery pack, a heat dissipation structure is set on the top of the battery 1 component to accelerate the heat dissipation. At the same time, the part of the battery module 102 that contacts the sealing cover 103 dissipates heat faster and has a low temperature. There will be a large heat transfer temperature difference in the vertical direction. The greater the heat transfer amount, the greater the temperature difference, and the faster the insulating liquid 5 rises and flows after vaporization, thereby accelerating the heat dissipation efficiency, making the temperature difference of the battery module 102 smaller, ensuring the temperature uniformity of the battery pack under working conditions, and ensuring the life, performance and safety of the battery pack.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A battery, comprising a housing and a cell assembly disposed in the housing, characterized in that: A preset mass of insulating liquid is injected into the shell, the liquid level of the preset mass of insulating liquid in the shell is lower than the height of the battery cell assembly, and the preset mass of the insulating liquid is in a predetermined ratio to the difference between the total calorific value of the battery and the heat required for the battery to rise from an initial temperature to a maximum design temperature; The preset mass of the insulating liquid is according to the formula: To determine, where A is a predetermined constant, and A ≥ 1, is the specific heat capacity of the insulating liquid, is the boiling point of the insulating liquid, For normal temperature, is the total heat generated by the battery, The heat required for the battery to rise from its initial temperature to its maximum design temperature; In the formula: In, 1.3>A≥1.

2. A battery as claimed in claim 1, characterized in that: There are several battery cell assemblies, and two adjacent battery cell assemblies are electrically connected via a connecting structure. A partition is provided between two adjacent battery cell assemblies, and the partition is used to separate and fix the battery cell assemblies, and there is a gap between the partition and the shell.

3. A battery as claimed in claim 1, characterized in that: The shell comprises an outer shell with an opening and a cover plate covering the opening. The battery cell assembly is loaded into the outer shell through the opening. A receiving cavity for storing the insulating liquid is formed between the outer shell and the battery cell assembly.

4. A battery as claimed in claim 3, characterized in that: The cover plate is provided with a liquid injection hole for injecting the insulating liquid into the accommodating cavity.

5. A battery as claimed in claim 4, characterized in that: The liquid injection hole is located above the liquid level of the insulating liquid in the accommodating cavity.

6. A battery as claimed in claim 3, characterized in that: A pressure sensor is arranged in the accommodating cavity, and an explosion-proof structure is arranged in the shell.

7. A battery pack, comprising a tray, a high-voltage distribution box, a battery module and a sealing cover, wherein the battery module is installed in the tray, the high-voltage distribution box is electrically connected to the battery module, the sealing cover is sealed on the top of the battery module and fixed to the tray by a locking member, characterized in that: The sealing cover is provided with a heat dissipation structure, and the battery module comprises a plurality of batteries as described in any one of claims 1 to 6.

8. A battery pack as claimed in claim 7, characterized in that: In the battery module, a plurality of the batteries are arranged along a set direction, and along the set direction, the liquid level of the insulating liquid in the battery close to the tray frame is lower than the liquid level of the insulating liquid in the battery close to the center of the tray.

9. A battery pack according to claim 6 or 7, characterized in that: The heat dissipation structure is a liquid cooling plate and / or a fin structure.

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