Lithium ion battery pack convenient for temperature control

Abstract

The invention discloses a lithium ion battery pack convenient for temperature control. The lithium ion battery pack comprises a lithium ion battery pack body and a temperature control assembly, the lithium ion battery pack body comprises a plurality of battery cell monomers which are arranged in parallel; in the temperature control assembly, a plurality of battery cell mounting grooves and temperature adjusting grooves are longitudinally formed in the upper end of a heat-conducting insulating partition plate; a plurality of battery cell monomers are respectively arranged in the plurality of battery cell mounting grooves; a liquid cooling side plate and an electric heating film are embedded in the temperature adjusting groove; a liquid cooling bottom plate is arranged at the bottom ends of the heat-conducting insulating partition plate and the liquid cooling side plates; a liquid cooling top plate is arranged at the top ends of the liquid cooling side plates; the interiors of the liquid cooling bottom plate, the liquid cooling side plates and the liquid cooling top plate are communicated with one another; a plurality of heat dissipation grooves are formed in the heat-conducting insulating partition plate around each battery cell monomer; a heat insulation plate is arranged in each heat dissipation groove; and a plurality of phase change material layers are arranged in each heat insulation plate. According to the lithium ion battery pack convenient for temperature control provided by the invention, the reasonable and effective temperature control assembly is designed, and the lithium ion battery pack has a high-temperature heat dissipation function and a low-temperature rapid heating and preheating function for batteries.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium-ion batteries, and particularly to a lithium-ion battery pack facilitating temperature control. Background Art

[0002] In recent years, lithium-ion batteries have been widely used as power sources for electric vehicles or electric cars because of their large energy capacity, low self-discharge rate and no memory effect.

[0003] However, the battery packs of electric vehicles or electric cars are usually composed of a large number of single batteries closely arranged. They will continuously generate heat during operation. If these heats cannot be dissipated in time and effectively, the battery temperature will continue to rise, eventually leading to thermal runaway. In the case of no good heat dissipation system, the heat accumulation cannot be released in time, and even there will be risks of fire and explosion.

[0004] Currently, the commonly used cooling methods for lithium-ion battery packs mainly include air cooling, liquid cooling, phase change cooling, heat pipe cooling, etc. Most of the single cooling methods for batteries are difficult to meet the heat dissipation requirements of lithium-ion battery packs in most cases, so they are often used in combination with other systems. However, the existing composite cooling methods for batteries often have complex thermal management systems and are not conducive to maintenance.

[0005] In a low-temperature environment (usually below 0°C), lithium-ion batteries will have problems such as serious capacity loss and shortened cycle life. In a low-temperature environment, the cruising range of electric vehicles and / or electric cars decreases, the charging speed is limited, and even the whole vehicle cannot start, which severely restricts the popularization and use of electric vehicles or electric cars in cold environments.

[0006] Chinese Patent with Publication No. CN 221978051U discloses a liquid cooling plate for a lithium-ion battery pack with a bionic tree-shaped fractal flow channel structure, including a lithium-ion battery pack and a liquid cooling plate group. The liquid cooling plate group is composed of a substrate and a cover plate. A coolant flow channel is designed on the substrate. The coolant flow channel is composed of an inlet main flow channel with one end as a flow channel inlet and an outlet main flow channel with one end as a flow channel outlet, and a plurality of cooling flow channels connected in parallel between the inlet main flow channel and the outlet main flow channel. This patent not only meets the heat dissipation requirements of the lithium-ion battery pack, improves the uniformity of the temperature distribution on the heat transfer surface, and improves the heat dissipation efficiency; but this patent also has the problem that the heat dissipation effect at the bottom end of the lithium-ion battery pack is better than that in other places of the battery pack, the heat dissipation is not uniform enough, and the heat dissipation method is also single.

[0007] The Chinese patent with the publication number CN119764679A discloses a self-heating device for lithium-ion batteries in a low-temperature environment, which includes a protective shell and a lithium-ion battery. A heating film is provided on the outer wall surface of the lithium-ion battery for rapidly heating the lithium-ion battery under low-temperature conditions. Especially in a low-temperature environment, the heating film can rapidly heat up, enabling the lithium-ion battery to quickly reach an appropriate operating temperature. Then the heating film is turned off, and the temperature control component provides subsequent heat preservation. In this patent, each lithium-ion battery is coated with a heating film. There are numerous electric heating films, resulting in complex wiring with the BMS and complex circuit design. The power supply device for numerous electric heating films is not clearly disclosed. Moreover, the electric heating film is directly coated on the outside of the lithium-ion battery, posing a high risk in terms of safety. If the heating film is locally overheated (such as >80 °C), it may cause lithium deposition or thermal runaway of the battery core; the coating process for single battery cores is complex, increasing the cost by about 5-10%.

[0008] It can be seen that the lithium-ion battery pack needs to dissipate heat at high temperatures (in summer) and also needs to be preheated and heated up at low temperatures (in winter) to ensure that the temperature of the battery core is controlled within the optimal operating temperature during the charge and discharge process of the battery pack, thus ensuring the battery life. Therefore, designing a battery temperature control system with a lower cost, reasonable effectiveness, and high safety, which has both a high-temperature heat dissipation function and a low-temperature rapid heating and preheating function for the battery pack, is of great significance. Summary of the Invention

[0009] In view of this, the present invention proposes a lithium-ion battery pack that is convenient for temperature control.

[0010] To achieve the above object, the present invention adopts the following technical solutions: A lithium-ion battery pack facilitating temperature control includes a lithium-ion battery pack body and a temperature control component; the lithium-ion battery pack body includes a plurality of cell monomers arranged in parallel; the temperature control component includes a heat-conducting and insulating partition, a liquid-cooled bottom plate, liquid-cooled side plates, a liquid-cooled top plate, an electric heating film, a heat-insulating plate, and a phase change material layer; a plurality of cell installation grooves are longitudinally formed at the upper end of the heat-conducting and insulating partition; a temperature adjustment groove is longitudinally and throughly formed at the upper end of the heat-conducting and insulating partition; a plurality of cell monomers are respectively embedded in the plurality of cell installation grooves; the temperature adjustment groove is composed of a transverse groove and a longitudinal groove that are connected; longitudinal grooves are formed in the middle of the heat-conducting and insulating partition between every two adjacent cell monomers, longitudinal grooves are formed in the middle of the heat-conducting and insulating partition outside the cell monomers at both side ends, and transverse grooves are respectively formed in the middle of the heat-conducting and insulating partition at the front and rear ends of all cell monomers; the liquid-cooled side plates are integrally composed of transverse liquid-cooled side plates and longitudinal liquid-cooled side plates; electric heating films are arranged on the side end faces of the liquid-cooled side plates close to each cell monomer; the liquid-cooled side plates and the electric heating films are embedded in the temperature adjustment groove; the liquid-cooled bottom plate is arranged at the bottom ends of the heat-conducting and insulating partition and the liquid-cooled side plates; the liquid-cooled top plate is arranged at the top ends of the liquid-cooled side plates; the interiors of the liquid-cooled bottom plate, the liquid-cooled side plates, and the liquid-cooled top plate are all hollow structures and are interconnected; the liquid-cooled bottom plate and the liquid-cooled top plate are respectively connected to a coolant inlet pipe and a coolant outlet pipe; a plurality of heat dissipation grooves are formed in the heat-conducting and insulating partition attached to the periphery of each cell monomer; each heat dissipation groove communicates with the cell monomer; a heat-insulating plate is attached to the inner wall of each heat dissipation groove; a plurality of phase change material layers are arranged on the end face of each heat-insulating plate facing the cell monomer; the phase change material layer is attached to the cell monomer.

[0011] Further, a plurality of inner partition plates are arranged in the liquid-cooled side plates from bottom to top, dividing the interior of the liquid-cooled side plates from bottom to top into a plurality of non-communicating flow guiding spaces; a plurality of liquid passing pipes are respectively arranged between every two adjacent inner partition plates along the length direction and the width direction of the plurality of cell monomers; the lower end opening of each liquid passing pipe communicates with the flow guiding space below it, and a coolant outlet is formed through the side wall of each liquid passing pipe; the liquid passing pipes in a plurality of adjacent flow guiding spaces are distributed in a staggered manner.

[0012] Further, the heat-conducting and insulating partition is made of a silicon-based heat-conducting and insulating pad; the cell monomer is square.

[0013] Further, the transverse slot at the front end and the longitudinal slot at one side end are not connected, the transverse slot at the front end and the longitudinal slot at the other side end are connected, and the transverse slot at the front end and all longitudinal slots between the two side ends are not connected; the transverse slot at the rear end is connected to all longitudinal slots; a plurality of ventilation holes are formed in the heat-conducting insulating partition between the transverse slot at the front end and the longitudinal slot at one side end; a first heat dissipation space is left between the outer wall of the liquid-cooling side plate near the ventilation hole and the inner wall of the transverse slot at the front end; a second heat dissipation space is left between the outer wall of the liquid-cooling side plate near the ventilation hole and the inner wall of the longitudinal slot at one side end; the first heat dissipation space and the second heat dissipation space are connected through the ventilation hole.

[0014] Further, the electric heating film is integrally and continuously connected by a plurality of layers of electric heating films and end electric heating films; each layer of electric heating film is integrally connected by a transverse electric heating film, a longitudinal electric heating film, and a U-shaped electric heating film; transverse electric heating films are respectively arranged on the inner sides of the transverse liquid-cooling side plates at the front end and the rear end; longitudinal electric heating films are respectively arranged on the inner sides of the longitudinal liquid-cooling side plates at both side ends; U-shaped electric heating films are arranged on the outer walls of all longitudinal liquid-cooling side plates between the longitudinal liquid-cooling side plates at both side ends.

[0015] Further, the interior of each inner partition board is a hollow structure; a plurality of ventilation pipes are arranged between every two adjacent inner partition boards; the upper end opening of each ventilation pipe is connected to the interior of the inner partition board above it, and the lower end opening of each ventilation pipe is connected to the interior of the inner partition board below it; a plurality of short exhaust pipes are arranged along the circumferential direction of each battery cell monomer on each ventilation pipe, short exhaust pipes are arranged on each ventilation pipe in the direction towards the first heat dissipation space, and short exhaust pipes are arranged on each ventilation pipe in the direction towards the second heat dissipation space; all short exhaust pipes are connected to the interior of the inner partition board, and all short exhaust pipes penetrate through the liquid-cooling side plate and do not extend out of the outer wall of the liquid-cooling side plate; the short exhaust pipes do not contact the electric heating film.

[0016] Further, the heat dissipation slot is T-shaped; a U-shaped slot is formed in the end face of the heat insulation board facing the battery cell monomer; a plurality of phase change material layers are respectively arranged in the U-shaped slot from top to bottom.

[0017] Further, the phase change material layer is made of microcapsule-encapsulated phase change material; the phase change material is a paraffin-based composite phase change material.

[0018] Further, it further includes end plates and steel belts; end plates are arranged at both side ends of the lithium-ion battery pack body; a steel belt is tightly sleeved on the outside of the lithium-ion battery pack body and the end plates. The lithium-ion battery pack body, the end plates, and the steel belts are all arranged in a protective housing; an elastic buffer plate is arranged between the protective housing and the steel belt.

[0019] Furthermore, the coolant inlet pipe and the coolant outlet pipe respectively penetrate and extend out of the protective housing; one end of the coolant inlet pipe extending out of the protective housing has two openings, namely a lower opening and a side opening, and the inner pipe walls of both openings are provided with internal threads; one end of the coolant outlet pipe extending out of the protective housing has two openings, namely a lower opening and a side opening, and the inner pipe walls of both openings are provided with internal threads.

[0020] Compared with the existing technology, the beneficial effects of the present invention are as follows: (1) For the temperature-controlled lithium-ion battery pack provided in this solution, the temperature of the coolant is transmitted to the heat-conducting and insulating partition through the liquid-cooled side plate. The heat-conducting and insulating partition has good heat conductivity, enabling good cooling effects around each cell monomer in each lithium-ion battery pack, and the cooling effects achieved by each cell monomer are basically the same; while in the traditional lithium-ion battery pack, the coolant pipes are arranged sequentially along each cell monomer. The cell monomers near the coolant inlet receive better cooling effects and the lowest coolant temperature, while the cell monomers near the coolant outlet receive poorer cooling effects and the coolant temperature has already risen. Therefore, the cooling effects of each cell in each module are inconsistent, which is not conducive to the thermal management of the battery. (2) For the temperature-controlled lithium-ion battery pack provided in this solution, the phase change materials around the cell monomers are all in contact with the cell monomers. When the cell monomers are at a high temperature, the heat dissipated can be absorbed by the phase change material layer, and the phase change material layer is basically only affected by the temperature of the cell monomers. (3) For the temperature-controlled lithium-ion battery pack provided in this solution, an air-cooling cooling method is set around each cell monomer to form a composite cooling solution. Compared with a single cooling solution, the composite cooling solution has a faster cooling rate and a better cooling effect on the lithium-ion battery pack, and is more likely to meet the safety operation requirements of the battery pack. (4) For the temperature-controlled lithium-ion battery pack provided in this solution, when the NTC at the top of the cell monomer in the lithium-ion battery pack detects that the temperature is lower than 0 °C, the BMS controls the electric heating film to start heating. After the lithium-ion battery pack is preheated and warmed up, the lithium-ion battery pack then operates normally. Description of the Drawings

[0021] Figure 1 Is a three-dimensional view of the temperature-controlled lithium-ion battery pack provided by the embodiment of the present invention; Figure 2 Is Figure 1 The enlarged view at A in Figure 3 Is Figure 1 The enlarged view at B in Figure 4 Is Figure 1Another perspective structural schematic diagram; Figure 5 Exploded view of the temperature-controlled lithium-ion battery pack provided by an embodiment of the present invention; Figure 6 Top view of the temperature-controlled lithium-ion battery pack provided by an embodiment of the present invention; Figure 7 For Figure 6 A-A sectional view in Figure 8 For Figure 7 Enlarged view at C in Figure 9 For Figure 6 B-B sectional view in Figure 10 For Figure 9 Enlarged view at D in Figure 11 For Figure 6 C-C sectional view in Figure 12 For Figure 6 D-D sectional view in Figure 13 For Figure 6 E-E sectional view in Figure 14 Stereogram of the heat-conducting and insulating separator provided by an embodiment of the present invention; Figure 15 Stereogram of the liquid-cooling side plate and the electric heating film provided by an embodiment of the present invention; Figure 16 Stereogram of the inner separator, the liquid pipe, and the gas pipe provided by an embodiment of the present invention; Figure 17 Front view of the inner separator, the liquid pipe, and the gas pipe provided by an embodiment of the present invention; Figure 18 Left view of the inner separator, the liquid pipe, and the gas pipe provided by an embodiment of the present invention; Figure 19 Stereogram of the electric heating film provided by an embodiment of the present invention; Figure 20 Top view of the electric heating film provided by an embodiment of the present invention; Figure 21 Left view of the electric heating film provided by an embodiment of the present invention; Figure 22 Front view of the electric heating film provided by an embodiment of the present invention.

[0022] In the figure: 1, single battery cell; 2, heat-conducting insulating partition board; 3, liquid-cooling bottom plate; 4, liquid-cooling side plate; 41, horizontal liquid-cooling side plate; 42, vertical liquid-cooling side plate; 5, liquid-cooling top plate; 6, electric heating film; 61, horizontal electric heating film; 62, vertical electric heating film; 63, U-shaped electric heating film; 64, end electric heating film; 7, heat-insulating board; 8, phase-change material layer; 9, battery cell installation groove; 10, temperature-regulating groove; 101, horizontal groove; 102, vertical groove; 11, heat-dissipating groove; 12, coolant inlet pipe; 13, coolant outlet pipe; 14, inner partition board; 15, diversion space; 16, liquid-passage pipe; 17, coolant outlet; 18, elastic buffer plate; 19, first heat-dissipating space; 20, second heat-dissipating space; 21, ventilation pipe; 22, short air outlet pipe; 23, end plate; 24, steel strip; 25, protective housing. Detailed implementation manners

[0023] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0024] In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more; the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0025] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "connected" and "connected" 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 mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0026] Embodiment: As Figures 1 - 22As shown in the figure, a lithium-ion battery pack convenient for temperature control includes a lithium-ion battery pack body and a temperature control component. The lithium-ion battery pack body includes a plurality of cell monomers 1 arranged in parallel; end plates 23 are provided at both ends of the lithium-ion battery pack body; a steel strip 24 is tightly sleeved on the outer sides of the lithium-ion battery pack body and the end plates 23. The cell monomer 1 is square. The temperature control component includes a heat-conducting and insulating partition 2, a liquid-cooled bottom plate 3, liquid-cooled side plates 4, an inner partition plate 14, a liquid pipe 16, a ventilation pipe 21, a liquid-cooled top plate 5, an electric heating film 6, a heat-insulating plate 7, and a phase change material layer 8.

[0027] The heat-conducting and insulating partition 2 is made of the HWF850 series silicon-based heat-conducting and insulating pad of Huimei Thermal Management Technology Co., Ltd., which has good heat conductivity, insulation characteristics, and certain elasticity and mechanical support (the mechanical support performance provides mechanical protection, buffers the expansion force of the battery cells, prevents the shell from cracking, and has excellent tear resistance and puncture resistance). The heat-conducting and insulating partition 2 plays a role in isolating, insulating, and buffering the cell monomers 1, and transfers the heat around the cell monomers 1 to the temperature control component.

[0028] A plurality of cell installation grooves 9 are longitudinally opened at the upper end of the heat-conducting and insulating partition 2; a temperature adjustment groove 10 is longitudinally penetrated and opened at the upper end of the heat-conducting and insulating partition 2. A plurality of cell monomers 1 are respectively embedded in the plurality of cell installation grooves 9.

[0029] The temperature adjustment groove 10 is composed of a transverse groove 101 and a longitudinal groove 102 that are connected. Longitudinal grooves 102 are opened in the middle of the heat-conducting and insulating partition 2 between every two adjacent cell monomers 1, and longitudinal grooves 102 are opened in the middle of the heat-conducting and insulating partition 2 outside the cell monomers 1 at both ends. Transverse grooves 101 are respectively opened in the middle of the heat-conducting and insulating partition 2 at the front and rear ends of all cell monomers 1. The transverse groove 101 at the front end is not connected to the longitudinal groove 102 at one side end, the transverse groove 101 at the front end is connected to the longitudinal groove 102 at the other side end, and the transverse groove 101 at the front end is not connected to all the longitudinal grooves 102 between the two side ends; the transverse groove 101 at the rear end is connected to all the longitudinal grooves 102.

[0030] A plurality of ventilation holes are horizontally opened from bottom to top in the heat-conducting and insulating partition 2 between the transverse groove 101 at the front end and the longitudinal groove 102 at one side end. A first heat dissipation space 19 is left between the outer wall of the liquid-cooled side plate 4 close to the ventilation hole and the inner wall of the transverse groove 101 at the front end; a second heat dissipation space 20 is left between the outer wall of the liquid-cooled side plate 4 close to the ventilation hole and the inner wall of the longitudinal groove 102 at one side end; the first heat dissipation space 19 and the second heat dissipation space 20 are connected through the ventilation holes.

[0031] The liquid-cooled side plate 4 is integrally composed of a transverse liquid-cooled side plate 41 and a longitudinal liquid-cooled side plate 42; an electric heating film 6 is provided on the side end face of the liquid-cooled side plate 4 close to each cell monomer 1; the liquid-cooled side plate 4 and the electric heating film 6 are embedded in the temperature adjustment groove 10.

[0032] The electric heating film 6 is integrally and continuously connected by multiple layers of electric heating films and an end electric heating film 64.

[0033] Each layer of the electric heating film 6 is integrally connected by a transverse electric heating film 61, a longitudinal electric heating film 62, and a U-shaped electric heating film 63. The inner sides of the front and rear transverse liquid cooling side plates 41 are respectively provided with transverse electric heating films 61; the inner sides of the longitudinal liquid cooling side plates 42 at both ends are respectively provided with longitudinal electric heating films 62; U-shaped electric heating films 63 are provided on the outer walls of all the longitudinal liquid cooling side plates 42 between the longitudinal liquid cooling side plates 42 at both ends. As shown by Figures 19 - 22 shown, the transverse electric heating film 61 at the front end, the longitudinal electric heating film 62 at the side end, the transverse electric heating film 61 at the rear end, the U-shaped electric heating film 63, and the longitudinal electric heating film 62 at the side end of each layer are integrally and continuously connected, and the multiple layers of electric heating films and the end electric heating film 64 are integrally and continuously connected, making the electric heating film 6 a complete electric heating film, rather than being composed of multiple electric heating films. The complete electric heating film is also convenient for wiring the electric heating film.

[0034] The basic circuit composition is as follows: the positive pole of the battery module is electrically connected to the fuse, the fuse is electrically connected to the relay, the relay is electrically connected to the electric heating film 6, and the electric heating film 6 is electrically connected to the negative pole of the battery module. Among them, the fuse prevents overcurrent or short circuit from damaging the circuit. The relay is controlled by the battery management system (BMS) to be turned on and off to realize the start and stop of heating.

[0035] The electric heating film is electrically connected to the BMS, and the electric heating film is controlled by the BMS to be turned on and off.

[0036] A thermistor (NTC) is used to monitor the temperature of the electric heating film 6. The NTC is attached to the surface of the electric heating film 6 through heat-conducting glue and is located between the electric heating film 6 and the heat-conducting insulation partition 2 to monitor the temperature of the electric heating film 6. All the NTCs are electrically connected to the BMS.

[0037] At least 3 cell monomers 1 are selected in each module to install NTCs. Generally, the NTCs are installed on the surfaces of the middle cell monomer 1 and the edge cell monomer 1. The NTCs are welded on the FPC and are indirectly in contact with the cell monomer 1 through a silica gel heat-conducting pad. The thickness of the silica gel heat-conducting pad is usually 0.1 - 0.5 mm. The NTCs directly monitor the surface temperature of the cell monomer 1. The alarm is provided with a high-temperature threshold (55 °C) and a low-temperature threshold (0 °C). The silica gel heat-conducting pad ensures good heat conduction, and at the same time can play a certain buffering and protection role to reduce the damage to the NTC caused by vibration, impact, etc.

[0038] When the BMS detects that the temperature of the lithium-ion battery pack is lower than the low-temperature threshold, the relay is activated to turn on the heating circuit. The electric heating film starts to be powered on. After the electric heating film 6 is powered on, the conductive layer material of the electric heating film conducts heat and generates heat. The NTC feeds back to control the temperature, and cooperates with the BMS to achieve precise temperature control.

[0039] The interior of each inner partition plate 14 is a hollow structure; several ventilation pipes 21 are provided between every two adjacent inner partition plates 14; the upper opening of each ventilation pipe 21 communicates with the interior of the upper inner partition plate 14, and the lower opening of each ventilation pipe 21 communicates with the interior of the lower inner partition plate 14; several short exhaust pipes 22 are provided along the circumferential direction of each battery cell 1 for each ventilation pipe 21, the short exhaust pipes 22 are provided in the direction of the first heat dissipation space 19 for each ventilation pipe 21, and the short exhaust pipes 22 are provided in the direction of the second heat dissipation space 20 for each ventilation pipe 21. All the short exhaust pipes 22 communicate with the interior of the inner partition plate 14, and all the short exhaust pipes 22 penetrate through the liquid cooling side plate 4 and do not protrude from the outer wall of the liquid cooling side plate 4; the short exhaust pipes 22 do not contact the electric heating film 6.

[0040] A liquid cooling bottom plate 3 is provided at the bottom ends of the heat-conducting insulating partition plate 2 and the liquid cooling side plate 4; a liquid cooling top plate 5 is provided at the top end of the liquid cooling side plate 4; the interiors of the liquid cooling bottom plate 3, the liquid cooling side plate 4, and the liquid cooling top plate 5 are all hollow structures and are interconnected; the liquid cooling bottom plate 3 and the liquid cooling top plate 5 are respectively connected to the coolant inlet pipe 12 and the coolant outlet pipe 13.

[0041] A plurality of heat dissipation grooves 11 are formed on the heat-conducting insulating partition plate 2 attached to the periphery of each battery cell 1. The heat dissipation grooves 11 are T-shaped, and each heat dissipation groove 11 communicates with the battery cell 1. A heat insulation plate 7 is attached to the inner wall of each heat dissipation groove 11; a U-shaped groove is formed on the end face of the heat insulation plate 7 close to the battery cell 1. A plurality of phase change material layers 8 are respectively provided in the U-shaped groove from top to bottom, and each phase change material layer 8 is attached to the battery cell 1. The direct contact between the phase change material layer 8 and the battery cell 1 can maximize the heat conduction efficiency.

[0042] The phase change material layer 8 is made of microcapsule-encapsulated phase change material. The phase change material is encapsulated by microcapsule technology to prevent leakage and extend the service life; the phase change material is a paraffin-based composite phase change material, such as paraffin / expanded graphite composite phase change material. The phase change material layer 8 made of microcapsule-encapsulated phase change material is spherical, and the particle size of a single phase change material layer 8 is 10 - 50 μm. When subjected to external force, the spherical phase change material layer 8 can better disperse stress and reduce the risk of microcapsule rupture.

[0043] Phase change materials will undergo a phase change when the temperature reaches their phase change points, changing from a solid state to a liquid state. During this process, the phase change materials will absorb a large amount of heat, thereby playing a role in cooling the battery. When the temperature of the lithium-ion battery drops, the phase change materials will change back from a liquid state to a solid state, releasing the heat absorbed before. This cycle has the property of being reusable.

[0044] The paraffin / expanded graphite composite phase change material can effectively inhibit the temperature rise of the battery by absorbing the heat generated during the operation of the lithium-ion battery, improving the safety and lifespan of the lithium-ion battery. The advantages achieved are as follows: no additional energy consumption is required, which is suitable for the lightweight and energy-saving requirements of electric vehicles or electric cars; the high latent heat characteristic of the phase change material can reduce the temperature difference inside the battery pack and avoid local overheating; it can be combined with a liquid cooling active heat dissipation system to form a composite cooling solution to cope with extreme working conditions.

[0045] Inside the liquid cooling side plate 4, several internal partition plates 14 are arranged from bottom to top, dividing the inside of the liquid cooling side plate 4 from bottom to top into several non-connected flow guiding spaces 15; between every two adjacent internal partition plates 14, several liquid passing tubes 16 are respectively arranged along the length direction and width direction of several battery cell monomers 1; the lower end opening of each liquid passing tube 16 is connected to the flow guiding space 15 below it, and the side wall of each liquid passing tube 16 is penetrated with a coolant outlet 17; the several liquid passing tubes 16 in every two adjacent flow guiding spaces 15 are arranged in a staggered manner.

[0046] The lithium-ion battery pack body, end plates 23, and steel strips 24 are all arranged inside a protective housing 25; an elastic buffer plate 18 is arranged between the protective housing 25 and the steel strip 24.

[0047] The coolant inlet pipe 12 and the coolant outlet pipe 13 respectively penetrate and extend out of the protective housing 25. One end of the coolant inlet pipe 12 that penetrates and extends out of the protective housing 25 has two openings, which are respectively a lower end opening and a side end opening, and the inner tube walls of both openings are provided with internal threads; one end of the coolant outlet pipe 13 that penetrates and extends out of the protective housing 25 has two openings, which are respectively a lower end opening and a side end opening, and the inner tube walls of both openings are provided with internal threads.

[0048] Above the lithium-ion battery pack body is provided with a CCS component. The CCS component can adopt the market-regular CCS component and installation method. The core structure of the regular CCS component includes: a signal acquisition component, a conductive structure, and an insulation and support system. The signal acquisition component, the conductive structure, and the insulation and support system can be connected into a whole through processes such as thermal pressing or riveting to achieve the functions of high-voltage series and parallel connection of battery cells, temperature sampling of the battery, voltage sampling of battery cells, and short-circuit protection function of the sampling line. Among them, the signal acquisition component can adopt a flexible printed circuit board (FPC) to integrate the voltage and temperature acquisition units; the conductive structure can adopt copper-aluminum busbars for laser welding series and parallel connection of battery cells to form a high-voltage connection path to ensure tight and reliable electrical connection between each battery cell monomer 1; the insulation and support system can adopt a plastic suction board to provide mechanical support and insulation protection to ensure that they can still maintain a stable connection state under harsh environments such as vibration and impact. The CCS component is a key component in the battery module responsible for the electrical connection between battery cell monomers 1, which can ensure the smooth flow of current between battery cell monomers 1, thereby realizing the storage and release of electrical energy.

[0049] The upper cover is provided at the upper ends of the protective housing 25 and the CCS component to form a closed external protection structure.

[0050] If a single lithium-ion battery pack is adopted for the lithium-ion battery pack, the lower end opening of the coolant inlet pipe 12 is blocked by a threaded connection plug, the lower end opening of the coolant outlet pipe 13 is blocked by a threaded connection plug, the side end opening of the coolant inlet pipe 12 and the outlet water pipe are connected by a quick connector, and the side end opening of the coolant outlet pipe 13 and the return water pipe are connected by a quick connector.

[0051] The coolant is (ethylene glycol-water mixture). The water pump pressurizes the coolant and pumps it into the hydraulic bottom plate at a certain flow rate. When the coolant flows through the liquid cooling bottom plate 3, liquid cooling side plate 4, and liquid cooling top plate 5 inside the lithium-ion battery pack in sequence, it absorbs heat and warms up, and then enters the heat exchanger through the return water pipe of the (electric vehicle or electric car) cooling system for cooling; in the heat exchanger, the coolant exchanges heat with the refrigerant of the (electric vehicle or electric car) air-conditioning system, and the temperature of the coolant is reduced through the process of refrigerant evaporation and heat absorption; the cooled coolant returns to the water pump through the outlet water pipe of the heat exchanger and is then pumped into the lithium-ion battery pack again, so on and so forth. The water pump can be electrically connected to the BMS.

[0052] If a single lithium-ion battery pack is adopted for the lithium-ion battery pack, a single-chip BMS solution can be adopted. The BMS main control chip is directly welded on the surface of the PCB board, and this PCB board can be fixed on the inner side of the upper cover or the plastic suction board of the CCS component.

[0053] If multiple lithium-ion battery packs are used in a lithium-ion battery pack, the side-end opening of the coolant inlet pipe 12 is sealed by threadedly connecting a plug, the side-end opening of the coolant outlet pipe 13 is sealed by threadedly connecting a plug, the lower-end openings of the respective coolant inlet pipes 12 of the multiple lithium-ion battery packs and the respective outlets on a hollow coolant input plate are connected in communication through quick connectors, and the coolant input plate and the water outlet pipe are connected in communication; the lower-end openings of the respective coolant outlet pipes 13 of the multiple lithium-ion battery packs and the respective inlets on a hollow coolant output plate are connected in communication through quick connectors, and the coolant output plate and the return water pipe are connected in communication. The coolant input plate and the coolant output plate can both be arranged on the battery chassis support frame.

[0054] The circulation process of the coolant is the same: the coolant is (ethylene glycol-water mixture). The water pump pressurizes the coolant and pumps it into the hydraulic bottom plate at a certain flow rate. The coolant absorbs heat and heats up when flowing through the liquid cooling bottom plate 3, liquid cooling side plate 4, and liquid cooling top plate 5 inside the lithium-ion battery pack in sequence, and enters the heat exchanger through the return water pipe of the cooling system for cooling; in the heat exchanger, the coolant exchanges heat with the refrigerant of the air-conditioning system, and the temperature of the coolant is reduced through the process of refrigerant evaporation and heat absorption; the cooled coolant returns to the water pump through the outlet pipe of the heat exchanger and is then pumped into the lithium-ion battery pack again, and so on in a cycle. The water pump can be electrically connected to the BMS.

[0055] If multiple lithium-ion battery packs are used in a lithium-ion battery pack, the PCB board of each lithium-ion battery pack can be fixed on the inner side of its upper cover or on the plastic suction plate of the CCS component, and the main control board BMU can be installed in the center of the battery pack.

[0056] Working principle: When the NTC at the top of the battery cell 1 in the lithium-ion battery pack detects that the temperature is higher than the high-temperature threshold, the battery may undergo thermal runaway, resulting in battery capacity attenuation and performance degradation, and cooling is required.

[0057] The BMS controls the water pump to start working. The coolant enters the liquid cooling bottom plate 3 inside the lithium-ion battery pack through the outlet pipe, and then enters the liquid cooling side plate 4. The coolant in each flow guiding space 15 enters the flow guiding space 15 above it through the liquid passing pipe 16 at its top. After the coolant is horizontally transmitted, it then enters the flow guiding space 15 above through the lower-end opening of the liquid passing pipe 16 at the top of this flow guiding space 15, realizing the longitudinal transmission of the coolant. According to this principle, the coolant reaches the flow guiding space 15 at the topmost upper part. The topmost upper flow guiding space 15 is connected in communication with the liquid cooling top plate 5, and the coolant enters the liquid cooling top plate 5, and then enters the heat exchanger through the return water pipe (inside the electric vehicle or electric car) for cooling; in the heat exchanger, the temperature of the coolant is reduced, and the cooled coolant returns to the water pump through the outlet pipe of the heat exchanger and is then pumped into the lithium-ion battery pack again, and so on in a cycle.

[0058] In the present temperature control assembly, the arrangement methods of the liquid-cooled bottom plate 3, the liquid-cooled side plates 4, the inner partition plates 14, the liquid conduction pipes 16 and the liquid-cooled top plate 5 enable the coolant in the liquid-cooled bottom plate 3 to enter the liquid-cooled side plates 4 around each battery cell 1 simultaneously. The coolant undergoes lateral and longitudinal transmissions inside the liquid-cooled side plates 4, and the coolant around each battery cell 1 enters the liquid-cooled top plate 5 simultaneously. The coolant undergoes multiple lateral and longitudinal transmissions in each flow guiding space 15, and the transmission path is longer, so that the cooling effect received by the periphery of each battery cell 1 is better. The temperature of the coolant is transferred to the heat-conducting insulating partition plate 2 through the liquid-cooled side plates 4. The heat-conducting insulating partition plate 2 has good heat conductivity, so that good cooling effects can be achieved around each battery cell 1 in each lithium-ion battery pack, and the cooling effects achieved by each battery cell 1 are basically the same.

[0059] In the present temperature control assembly, the arrangement methods of the heat dissipation grooves 11, the heat insulating plates 7 and the phase change material layer 8, the heat insulating plates 7 prevent the temperature of the heat-conducting insulating partition plate 2 from being transferred to the phase change material layer 8, and the phase change materials around the battery cells 1 are all in contact with the battery cells 1. When the battery cells 1 are at a high temperature, the heat dissipated can be absorbed by the phase change material layer 8.

[0060] In the present temperature control assembly, the arrangement methods of the inner partition plates 14, the air conduction pipes 21 and the short air outlet pipes 22 enable the high-temperature gas inside the lithium-ion battery pack to enter the interiors of the inner partition plates 14 through the short air outlet pipes 22. Since the inner partition plates 14 are immersed in the coolant of the liquid-cooled side plates 4, the high-temperature gas in each inner partition plate 14 also exchanges heat with the coolant, and the cooled gas is then discharged through the short air outlet pipes 22 on each inner partition plate 14 to perform air cooling on the heat-conducting insulating partition plate 2 around each battery cell 1, forming a composite cooling scheme. The short air outlet pipes 22 distributed outside the heat-conducting insulating partition plate 2 around each battery cell 1 are all communicated with the first heat dissipation space 19 and the second heat dissipation space 20.

[0061] Compared with a single cooling scheme, the composite cooling scheme has a faster cooling rate and a better cooling effect on the lithium-ion battery pack, and it is easier to meet the requirements for the safe operation of the battery pack.

[0062] When the NTC at the top of the battery cell 1 in the lithium-ion battery pack detects that the temperature is lower than the low temperature threshold, it is necessary to preheat and raise the temperature of the battery.

[0063] The BMS controls the electric heating film 6 to start heating. When the NTC at the top of the cell unit 1 in the lithium-ion battery pack detects that the temperature is higher than 10 °C, the BMS controls the electric heating film 6 to stop heating, and the preheating of the lithium-ion battery pack is completed. The heat conductivity of this heat-conducting and insulating separator 2 is good. When the electric heating film is heated, the heat is transferred to the heat-conducting and insulating separator 2, and then transferred to each cell unit 1 through the heat-conducting and insulating separator 2. Since the electric heating film 6 is arranged around each cell unit 1 in each lithium-ion battery pack, a good heating and temperature-rising effect can be achieved around each cell unit 1 in each lithium-ion battery pack, and the temperature-rising effect achieved by each cell unit 1 is basically the same.

[0064] During the preheating and temperature-rising process of the lithium-ion battery pack, the heat insulation board 7 prevents the temperature of the heat-conducting and insulating separator 2 from being transferred to the phase change material layer 8, and the phase change material layer 8 is basically only affected by the temperature of the cell unit 1.

[0065] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A lithium-ion battery pack facilitating temperature control, comprising a lithium-ion battery pack body and a temperature control component; the lithium-ion battery pack body includes a plurality of cell monomers arranged in parallel; characterized in that, The temperature control component includes a thermally conductive and insulating partition, a liquid-cooled bottom plate, liquid-cooled side plates, a liquid-cooled top plate, an electric heating film, a heat insulation plate, and a phase change material layer; a plurality of battery cell installation grooves are longitudinally formed at the upper end of the thermally conductive and insulating partition; a temperature adjustment groove is longitudinally formed through the upper end of the thermally conductive and insulating partition; a plurality of battery cell monomers are respectively embedded in the plurality of battery cell installation grooves; the temperature adjustment groove is composed of a transverse groove and a longitudinal groove that are communicated with each other. A longitudinal groove is formed in the middle of the thermally conductive and insulating partition between every two adjacent battery cell monomers, and a longitudinal groove is formed in the middle of the thermally conductive and insulating partition outside the battery cell monomers at both ends. Transverse grooves are respectively formed in the middle of the thermally conductive and insulating partition at the front end and the rear end of all the battery cell monomers; the liquid-cooled side plate is integrally formed by a transverse liquid-cooled side plate and a longitudinal liquid-cooled side plate; an electric heating film is provided on the side end face of the liquid-cooled side plate close to each battery cell monomer; the liquid-cooled side plate and the electric heating film are embedded in the temperature adjustment groove; the liquid-cooled bottom plate is provided at the bottom ends of the thermally conductive and insulating partition and the liquid-cooled side plate; the liquid-cooled top plate is provided at the top end of the liquid-cooled side plate; the interiors of the liquid-cooled bottom plate, the liquid-cooled side plates, and the liquid-cooled top plate are all hollow structures and are communicated with each other; the liquid-cooled bottom plate and the liquid-cooled top plate are respectively connected to a coolant inlet pipe and a coolant outlet pipe; a plurality of heat dissipation grooves are formed in the thermally conductive and insulating partition that is in contact with the periphery of each battery cell monomer; each heat dissipation groove is communicated with the battery cell monomer; a heat insulation plate is adhesively provided on the inner wall of each heat dissipation groove; a plurality of phase change material layers are provided on the end face of each heat insulation plate facing the battery cell monomer; the phase change material layer is in contact with the battery cell monomer.

2. The lithium-ion battery pack convenient for temperature control according to claim 1, wherein, A plurality of inner partition plates are provided in the liquid-cooled side plate from bottom to top, dividing the interior of the liquid-cooled side plate from bottom to top into a plurality of non-communicating flow guiding spaces; a plurality of liquid passing pipes are respectively provided between every two adjacent inner partition plates along the length direction and the width direction of the plurality of battery cell monomers; the lower end opening of each liquid passing pipe is communicated with the flow guiding space below it, and a coolant outlet is formed through the side wall of each liquid passing pipe; the plurality of liquid passing pipes in every two adjacent flow guiding spaces are distributed in a staggered manner.

3. The lithium-ion battery pack convenient for temperature control according to claim 1, wherein The thermally conductive and insulating partition is made of a silicon-based thermally conductive and insulating pad; The battery cell monomer is square.

4. A lithium-ion battery pack facilitating temperature control according to claim 2, characterized in that, The transverse groove at the front end is not communicated with the longitudinal groove at one side end, the transverse groove at the front end is communicated with the longitudinal groove at the other side end, and the transverse groove at the front end is not communicated with all the longitudinal grooves between the two side ends; the transverse groove at the rear end is communicated with all the longitudinal grooves; A plurality of ventilation holes are formed in the thermally conductive and insulating partition between the transverse groove at the front end and the longitudinal groove at one side end; a first heat dissipation space is left between the outer wall of the liquid-cooled side plate close to the ventilation hole and the inner wall of the transverse groove at the front end; a second heat dissipation space is left between the outer wall of the liquid-cooled side plate close to the ventilation hole and the inner wall of the longitudinal groove at one side end; the first heat dissipation space and the second heat dissipation space are communicated through the ventilation hole.

5. The lithium-ion battery pack convenient for temperature control according to claim 4, wherein The electric heating film is integrally and continuously connected by a plurality of layers of electric heating films and end electric heating films; Each layer of the electric heating film is integrally connected by a transverse electric heating film, a longitudinal electric heating film and a U-shaped electric heating film; the transverse electric heating films are respectively arranged on the inner sides of the transverse liquid cooling side plates at the front end and the rear end; the longitudinal electric heating films are respectively arranged on the inner sides of the longitudinal liquid cooling side plates at both ends; the U-shaped electric heating films are arranged on the outer walls of all the longitudinal liquid cooling side plates between the longitudinal liquid cooling side plates at both ends.

6. The lithium-ion battery pack facilitating temperature control according to claim 5, wherein The interior of each inner partition plate is a hollow structure; a plurality of ventilation pipes are arranged between every two adjacent inner partition plates; the upper end opening of each ventilation pipe is communicated with the interior of the inner partition plate above it, and the lower end opening of each ventilation pipe is communicated with the interior of the inner partition plate below it; a plurality of short exhaust pipes are arranged along the circumferential direction of each battery cell around each ventilation pipe, a short exhaust pipe is arranged in the direction of the first heat dissipation space for each ventilation pipe, and a short exhaust pipe is arranged in the direction of the second heat dissipation space for each ventilation pipe. All the short exhaust pipes are communicated with the interior of the inner partition plate, and all the short exhaust pipes penetrate through the liquid cooling side plate and do not extend out of the outer wall of the liquid cooling side plate; the short exhaust pipes are not in contact with the electric heating film.

7. A lithium-ion battery pack facilitating temperature control according to claim 1, characterized in that, The heat dissipation groove is T-shaped; a U-shaped groove is formed in the end face of the heat insulation plate facing the battery cell; a plurality of phase change material layers are respectively arranged in the U-shaped groove from top to bottom.

8. A lithium-ion battery pack facilitating temperature control according to claim 7, characterized in that, The phase change material layer is made of microcapsule encapsulated phase change material; the phase change material is paraffin-based composite phase change material.

9. The lithium-ion battery pack convenient for temperature control according to claim 1, characterized in that, It further includes end plates and steel strips; end plates are arranged at both ends of the lithium-ion battery pack body; a steel strip is tightly sleeved on the outside of the lithium-ion battery pack body and the end plates. The lithium-ion battery pack body, the end plates and the steel strips are all arranged in a protective housing; an elastic buffer plate is arranged between the protective housing and the steel strip.

10. A lithium-ion battery pack convenient for temperature control according to claim 9, characterized in that, The coolant inlet pipe and the coolant outlet pipe respectively penetrate and extend out of the protective housing. One end of the coolant inlet pipe penetrating and extending out of the protective housing has two openings, which are a lower end opening and a side end opening respectively, and internal threads are provided on the inner pipe walls of the two openings. One end of the coolant outlet pipe penetrating and extending out of the protective housing has two openings, which are a lower end opening and a side end opening respectively, and internal threads are provided on the inner pipe walls of the two openings.

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