An immersion liquid-cooled lithium battery thermal management system that combines heat conduction and heat convection

Abstract

The present invention relates to an immersion liquid-cooled lithium battery thermal management system that integrates heat conduction and heat convection, and relates to the technical field of battery thermal management. It includes a lithium battery pack and a control component. The lithium battery pack is provided with a plurality of lithium battery cells, and the lithium battery pack is filled with a coolant insulating medium; the lithium battery pack is provided with a two-way channel structure, and the control component is installed on the two-way channel structure to control the flow direction and flow rate of the coolant. The present invention can not only effectively and quickly remove the temperature of the positive electrode tab, but also quickly remove the heat in the lithium battery pack when the cell needs to be heated.

Description

Technical Field

[0001] The present invention relates to the technical field of battery thermal management, and in particular to an immersion-type liquid-cooled lithium battery thermal management system that combines heat conduction and heat convection. Background Art

[0002] During the operation of lithium batteries, oxidation reactions occur at the positive electrode and reduction reactions occur at the negative electrode. The oxidation reaction at the positive electrode is usually accompanied by more electron transfer and ion migration. These processes may generate more heat, especially at the positive electrode ear of the battery cell, where the current is concentrated and the heat generated is large. The performance, life, and safety of the battery are closely related to temperature. High temperature and uneven temperature distribution will greatly reduce the cycle life and charge and discharge efficiency of the battery. If the temperature continues to rise and reaches the critical temperature of thermal runaway of the battery, it will cause the battery to catch fire or even explode. On the other hand, the internal resistance, heat generation, and energy consumption of lithium-ion batteries will increase in low temperature environments. Therefore, it is very important to control the battery to operate within the optimal temperature range, reduce the maximum temperature difference between batteries, and ensure the temperature uniformity between single cells.

[0003] Cold plate liquid cooling technology, "liquid cooling", uses liquid as a heat exchange medium, but traditional cold plate liquid cooling technology has limitations. Because the heat-generating part of the battery cell is mainly the pole ear, the cooling plate of the plate liquid cooling is at the bottom of the battery cell, so the pole ear cannot be cooled directly. Moreover, it is very difficult to cool the liquid cooling plate against the pole ear, which will affect the measurement and collection of the battery cell temperature and voltage. At present, the cooling plate is also arranged on the side, which still cannot solve the problem of heat dissipation of the pole ear. Summary of the invention

[0004] In order to solve at least one technical problem in the background technology, the present invention provides an immersion liquid-cooled lithium battery thermal management system that combines heat conduction and heat convection, which can not only effectively and quickly remove the temperature of the positive electrode tab, but also quickly remove the heat in the lithium battery pack when the battery cell needs to be heated.

[0005] To achieve the above-mentioned purpose, the present invention provides an immersion liquid-cooled lithium battery thermal management system that combines heat conduction and heat convection, including: a lithium battery pack and a control component, wherein a plurality of lithium battery cells are arranged inside the lithium battery pack, and the lithium battery pack is filled with a coolant insulating medium; the lithium battery pack is provided with a two-way channel structure, and the control component is installed on the two-way channel structure for controlling the flow direction and flow rate of the coolant.

[0006] Furthermore, the bidirectional channel structure includes a top parallel flow channel arranged on the upper side of the lithium battery pack and a bottom parallel flow channel arranged on the lower side of the lithium battery pack.

[0007] Furthermore, the control component includes a control panel, a temperature sensor and a solenoid valve, the solenoid valve is installed in the two-way channel structure, the temperature sensor is attached to the lithium battery cell, and the control panel is communicatively connected to the temperature sensor and the solenoid valve respectively.

[0008] Furthermore, it also includes an oil cooler, which is connected to the top parallel flow channel.

[0009] Furthermore, it also includes a heating device, which is connected to the bottom parallel flow channel.

[0010] The beneficial effects of the present invention are:

[0011] 1) Through the design of top parallel flow channels and bottom parallel flow channels, effective control of the temperature difference of lithium battery cells is achieved.

[0012] 2) The forced flow of coolant insulating medium and the use of oil cooler improve the thermal management efficiency.

[0013] 3) The system can automatically adjust according to the temperature to meet the thermal management requirements under different working conditions.

[0014] 4) Improved the performance, service life and safety of lithium batteries.

[0015] 5) It can be effectively applied to the reuse of second-life batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a three-dimensional structural schematic diagram of the present invention;

[0017] Figure 2 It is a schematic diagram of the internal structure of the present invention;

[0018] Figure 3 is a flow diagram of the coolant insulating medium in the first case of the embodiment of the present invention;

[0019] Figure 4 is a flow diagram of the coolant insulating medium in the second case of the embodiment of the present invention;

[0020] Figure 5 3 is a flow diagram of the coolant insulating medium in the third case in the embodiment of the present invention.

[0021] Among them, in the figure:

[0022] 1-lithium battery pack; 2-lithium battery cell; 3-top parallel flow channel; 4-bottom parallel flow channel; 5-coolant insulating medium. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0025] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0026] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0027] In addition, the terms "installed", "set", "provided with", "connected", "connected", and "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0028] The present invention aims to solve the following technical problems: 1) How to effectively reduce the high temperature problem at the positive electrode tab position of the lithium battery cell during the charging and discharging process; 2) How to reduce the temperature difference between the positive and negative electrodes of the lithium battery cell to improve the overall performance and safety of the battery; 3) How to achieve automatic adjustment of the lithium battery thermal management system to adapt to the thermal management requirements under different ambient temperatures.

[0029] The purpose of the present invention is to effectively solve the temperature difference problem of lithium battery cells during use, as well as the temperature problem of the positive and negative pole tabs, and improve the thermal management efficiency and safety of the battery. Figure 1-2 As shown, the present invention provides an immersion liquid-cooled lithium battery thermal management system that combines heat conduction and heat convection, including: a lithium battery pack 1 and a control component, wherein the lithium battery pack 1 is provided with a plurality of lithium battery cells 2, and the lithium battery pack 1 is filled with a coolant insulating medium 5; the lithium battery pack 1 is provided with a two-way channel structure, and the control component is installed on the two-way channel structure to control the flow direction and flow rate of the coolant. The coolant insulating medium 5 adopts a silicon-based coolant insulating medium. The present invention can be effectively applied to cascade batteries, and well solves the problems of reliability and life of cascade batteries. It helps to maintain the battery within the optimal operating temperature range, thereby extending the service life of the battery.

[0030] The bidirectional channel structure includes a top parallel flow channel 3 arranged on the upper side of the lithium battery pack 1 and a bottom parallel flow channel 4 arranged on the lower side of the lithium battery pack 1. The top parallel flow channel 3 is used to force the coolant insulating medium 5 to flow when the battery cell is in normal use, so as to quickly take away the temperature of the pole ear. The battery cell can be a heat conductor, and the temperature in the entire lithium battery pack 1 can be effectively kept consistent through the temperature-uniform insulating medium; the bottom parallel flow channel 4 is used for heating treatment at extremely low temperatures, mainly to solve the problem of uniform temperature of the coolant insulating medium 5 inside the lithium battery pack 1 at low temperatures. The design of the top parallel flow channel 3 and the bottom parallel flow channel 4 is optimized to achieve uniform flow of the coolant at the battery cell pole ear position and improve the heat exchange efficiency.

[0031] The control component includes a control panel, a temperature sensor and a solenoid valve. The solenoid valve is installed in the bidirectional channel structure. The temperature sensor is attached to the lithium battery cell 2. The control panel is communicated with the temperature sensor and the solenoid valve respectively, and is used to adapt and open the top parallel flow channel 3 or the bottom parallel flow channel 4 according to the temperature to control the flow direction and flow rate of the coolant insulating medium 5.

[0032] The present invention further comprises an oil cooler, which is connected to the top parallel flow channel 3 and is used for cooling the coolant flowing in the top parallel flow channel 3 .

[0033] The present invention further comprises a heating device, which is connected to the bottom parallel flow channel 4 .

[0034] The design of the top parallel flow channel and the bottom parallel flow channel of the present invention can effectively control the temperature difference of the lithium battery cell to 2-3° C. Due to the temperature uniformity of the coolant, the battery is placed in a temperature environment more suitable for working.

[0035] The present invention realizes effective control of the temperature difference of lithium battery cells through the design of top parallel flow channels and bottom parallel flow channels. The forced flow of coolant insulating medium and the use of oil cooler improve the thermal management efficiency. The system can automatically adjust according to the temperature to meet the thermal management requirements under different working conditions. The performance, service life and safety of lithium batteries are improved. It can be effectively applied to the reuse of cascade batteries.

[0036] Example

[0037] The present invention uses a two-way channel structure to respectively manage heat under different working conditions. The top and bottom parallel flow channels directly absorb the heat at the battery cell tabs through the forced circulation of the coolant, and dissipate the heat through the oil cooler. The bottom parallel flow channel heats the coolant through a heating device in a low-temperature environment, thereby providing a suitable working temperature for the battery; the control surface automatically adjusts the opening and closing of the top parallel flow channel and the bottom parallel flow channel according to the real-time monitored battery temperature. The top parallel flow channel is opened in normal application, and the bottom parallel flow channel is opened when low-temperature heating is required. The two channels can also be opened at the same time, and high and low staggered flow channels can also be opened.

[0038] The first case: reference Figure 3 The top parallel flow channel can quickly take away the temperature of the positive pole ear, and the heat dissipation effect is good. It cannot solve the situation where the lithium battery pack needs to be heated, especially when the outdoor temperature is around minus 30℃, the temperature distribution of the coolant in the lithium battery pack is high at the top and low at the bottom, the oil temperature difference is as high as 40℃, and the battery temperature difference is also relatively large. The structure is simple.

[0039] The second case: Reference Figure 4 The parallel flow channel at the bottom can quickly remove the temperature of the lithium battery pack when heating is required, and the heating effect is good. It cannot effectively solve the temperature of the positive electrode ear.

[0040] The third case: reference Figure 5, with high and low staggered flow channels, the cold liquid at the bottom enters the lithium battery pack, and the hot liquid at the top flows out of the lithium battery pack. This is a relatively balanced thermal management method that achieves a good balance between heat dissipation and heating.

[0041] The fourth case: reference Figure 2 The dual-channel simultaneous opening mode can achieve both top cooling and bottom cooling, and can quickly achieve temperature balance of the lithium battery pack.

[0042] The invented system uses the battery cell as a heat transfer conductor, the coolant insulation medium as a temperature equalizer, and the flow of the top parallel flow channel quickly takes away the heat. This is an organic combination of heat conduction and heat convection. Whether it is the top parallel flow channel or the bottom parallel flow channel, or the organic combination of the two, it provides an optimal operating temperature condition for lithium batteries.

[0043] The present invention integrates the principles of heat conduction and heat convection to design a new type of immersion liquid-cooled lithium battery thermal management system. The system has a simple structure and high efficiency, can effectively solve the temperature difference problem of lithium batteries during use, and improve the thermal management performance and safety of batteries. The implementation of the present invention will help promote the development of new energy vehicles and energy storage industries, and contribute to the realization of dual carbon goals.

[0044] The above description is only a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any slight modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An immersion liquid-cooled lithium battery thermal management system that combines heat conduction and heat convection, characterized in that: include: A lithium battery pack and a control component, wherein the lithium battery pack has a plurality of lithium battery cells inside and is filled with a coolant insulating medium; the lithium battery pack is provided with a two-way channel structure, and the control component is mounted on the two-way channel structure to control the flow direction and flow rate of the coolant.

2. The immersion-type liquid-cooled lithium battery thermal management system integrating heat conduction and heat convection as claimed in claim 1, characterized in that: The bidirectional channel structure includes a top parallel flow channel arranged on the upper side of the lithium battery pack and a bottom parallel flow channel arranged on the lower side of the lithium battery pack.

3. The immersion type liquid-cooled lithium battery thermal management system integrating heat conduction and heat convection as claimed in claim 2, characterized in that: The control component includes a control panel, a temperature sensor and a solenoid valve. The solenoid valve is installed in the two-way channel structure. The temperature sensor is attached to the lithium battery cell. The control panel is respectively connected to the temperature sensor and the solenoid valve for communication.

4. The immersion-type liquid-cooled lithium battery thermal management system integrating heat conduction and heat convection as claimed in claim 3, characterized in that: It also includes an oil cooler, which is connected to the top parallel flow channel.

5. The immersion-type liquid-cooled lithium battery thermal management system integrating heat conduction and heat convection as claimed in claim 4, characterized in that: It also includes a heating device, which is connected to the bottom parallel flow channel.

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