CN110247130A - A kind of electrokinetic cell system based on cylindrical electrical core - Google Patents

Abstract

The invention discloses a power battery system based on a cylindrical battery cell, comprising a lower tray (100); a plurality of battery modules (200) are placed on the top of the lower tray (100); each battery module (200) includes front and rear Two brackets (5) distributed at intervals; each bracket (5) has multiple rows of cylindrical holes from top to bottom, and each cylindrical hole contained in each row of cylindrical holes is placed with a longitudinally distributed cylindrical electric A core (1); a serpentine tube (4) is arranged between any two adjacent rows of cylindrical holes; the left and right ends of each bracket (5) have vertically distributed, hollow end tubes (3); The left and right ends of each serpentine pipe (4) are respectively connected with an end pipe (3). The invention can reliably and effectively perform reliable heat management on the cylindrical battery system, timely cool and heat the battery cells, control the temperature difference between the battery cells, and ensure the temperature uniformity of the battery system.

Description

A power battery system based on cylindrical cells

technical field

The invention relates to the technical field of power batteries for new energy vehicles, in particular to a power battery system based on cylindrical batteries.

Background technique

At present, from a global perspective, the main energy source of new energy vehicles is batteries, especially lithium batteries. The basic technology of various new electric vehicles is still three-electric technology, especially lithium battery technology, including lithium battery cell technology and battery system technology . The types of batteries are roughly divided into round, square and soft pack batteries.

Compared with the square or pouch battery system, the main difficulty of the cylindrical battery system is that there are a large number of batteries, and the task of intelligent management of the batteries is heavy. In particular, each battery needs thermal management, and the integrated thermal management of each cylindrical battery module is required.

However, there is currently no technology that can reliably and effectively conduct reliable thermal management of cylindrical battery systems, cool and heat battery cells in time, control the temperature difference between battery cells, and ensure the stability of the battery system. temperature uniformity.

Contents of the invention

The purpose of the present invention is to provide a power battery system based on a cylindrical battery cell in view of the technical defects in the prior art.

To this end, the present invention provides a power battery system based on cylindrical cells, including a lower tray;

Multiple battery modules are placed on the top of the lower tray;

Each battery module includes two brackets spaced front and rear;

There are multiple rows of cylindrical holes in each bracket from top to bottom, and a longitudinally distributed cylindrical battery cell is placed in each cylindrical hole contained in each row of cylindrical holes;

A serpentine tube is arranged between any two adjacent rows of cylindrical holes;

The left and right ends of each bracket have vertically distributed and hollow end pipes respectively;

The left and right ends of each serpentine tube are respectively connected with an end tube.

Wherein, the upper part or the lower part of each end pipe is connected with a joint.

Wherein, the left and right ends of each serpentine tube are inserted and welded with an end tube respectively.

Wherein, the connector and the end pipe are interference fit.

Wherein, the end pipe is composed of a main pipe, a main pipe head, a plug and a branch pipe, wherein the plug is welded or bonded with the main pipe, the main pipe is welded with the main pipe, and the pipe branch is welded with the main pipe.

Wherein, the serpentine tube includes a hollow middle branch pipe, and the outside of the middle branch pipe is wrapped with heat-conducting glue.

Wherein, there is a main pipeline on the left and right sides of the support respectively;

A plurality of joints located at the left and right ends of the bracket communicate with adjacent main pipelines correspondingly.

Wherein, the lower tray includes a whole base plate composed of multiple base plates;

The overall rear end edge of the bottom plate is fixed with transversely distributed main pipe beams;

A plurality of longitudinal beams are fixedly arranged on the left and right edges of the bottom plate as a whole;

The whole middle part and the front end of the bottom plate are fixedly provided with beams.

Among them, the side of the main pipe beam located at the rear end of the lower tray is installed with a heat management main joint;

The thermal management main joint is connected with the main pipeline;

The thermal management header has two interfaces.

Among them, the side of the main pipe beam located at the rear end of the lower tray is also installed with high-voltage devices, total positive and negative joints and communication joints;

The high-voltage device is conductively connected with the total positive and negative connectors;

A series row is installed on the top of the battery module;

The outer cover of the plurality of battery modules has an upper cover;

Multiple second lifting lugs are welded at intervals on the longitudinal beam;

The left and right ends of the rear side of the main pipe beam are respectively welded with a first lifting lug.

It can be seen from the above technical solutions provided by the present invention that, compared with the prior art, the power battery system based on cylindrical batteries provided by the present invention can reliably and effectively perform reliable thermal management on cylindrical battery systems, and timely The battery cells are cooled and heated to control the temperature difference between the battery cells to ensure the temperature uniformity of the battery system, which can form an industrial scale, which is conducive to wide application and has great practical significance in production.

Description of drawings

Fig. 1 is a schematic diagram of the overall structure of a power battery system based on cylindrical cells provided by the present invention;

Fig. 2 is a schematic diagram of the overall structure of a power battery system based on cylindrical cells provided by the present invention when the upper cover is not fastened;

Fig. 3 is a top view of a power battery system based on cylindrical cells provided by the present invention when the upper cover is not fastened;

Fig. 4 is a front view of a battery module located at the front in a cylindrical cell-based power battery system provided by the present invention after assembly;

Fig. 5 is a front view of the assembled battery module in the middle of a power battery system based on cylindrical cells provided by the present invention;

Fig. 6 is a front view after assembly of the rear battery module in a power battery system based on cylindrical cells provided by the present invention;

Fig. 7 is an assembly schematic diagram of a thermal management structure of a battery module in a cylindrical cell-based power battery system provided by the present invention;

Fig. 8 is a front view of an end tube in a cylindrical cell-based power battery system provided by the present invention;

Fig. 9 is a side view of an end tube in a cylindrical cell-based power battery system provided by the present invention;

Fig. 10 is a top view of an end tube in a cylindrical cell-based power battery system provided by the present invention;

Fig. 11 is an enlarged schematic diagram of a serpentine tube in a cylindrical cell-based power battery system provided by the present invention;

Fig. 12 is an assembly schematic diagram of a thermal management structure in a cylindrical cell-based power battery system provided by the present invention;

Fig. 13 is a schematic diagram of the assembly of the lower tray and lifting lugs in a power battery system based on cylindrical cells provided by the present invention.

Detailed ways

In order to enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

Referring to Fig. 1 to Fig. 13, the present invention provides a power battery system based on cylindrical cells, including a lower tray 100;

A plurality of battery modules 200 are placed on the top of the lower tray 100;

Each battery module 200 includes two brackets 5 spaced forward and backward;

There are multiple rows of cylindrical holes in each bracket 5 from top to bottom, and a longitudinally distributed cylindrical battery cell 1 is placed in each cylindrical hole contained in each row of cylindrical holes;

A serpentine tube 4 is arranged between any two adjacent rows of cylindrical holes;

The left and right ends of each bracket 5 respectively have vertically distributed, hollow end pipes 3;

The left and right ends of each serpentine tube 4 are respectively connected with an end tube 3 .

In the present invention, specifically, the upper or lower part of each end pipe 3 is connected with a joint 2 .

It should be noted that, in actual implementation, the left and right ends of each serpentine tube 4 are plugged and welded with one end tube 3 respectively, so as to ensure the sealing reliability between the serpentine tube 4 and the end tube 3 . The joint 2 and the end pipe 3 are fitted in an interference fit to maintain sealing reliability, and a plurality of serpentine pipes 4 are connected in parallel to form a thermal management component of the module as a whole.

In the present invention, in terms of specific implementation, as shown in Figures 4 to 6, the battery module 200 can have the three structures shown in Figures 4 to 6, and of course, other structures including different numbers of batteries are also possible Not limited to the number shown in the figure.

In Fig. 4 to Fig. 6, the battery modules with three structures respectively include 7 strings, 3 strings and 11 strings of cells. In practical applications, they are respectively located at the front, middle and back of the system. Each module is composed of cell 1, connector 2, end tube 3, serpentine tube 4 and bracket 5. Each string is composed of multiple cells connected in parallel. The protection scope is not limited to the number of cells shown in the figure. Each module contains Two connectors 2, two end pipes 3, two brackets 5 and multiple serpentine pipes 4. The number of serpentine pipes 4 depends on the system height space and cell size, not limited to the five serpentine pipes shown in the figure .

In terms of specific implementation, the left and right joints 2 are the liquid inlet joint and the liquid outlet joint respectively. The positions of the two joints can be as shown in Figure 4 to Figure 6, or they can be at the diagonal position of the end pipe 3. All the serpentine pipes 4 Inside the module are parallel pipes that enter from left to right or from right to left. The heat exchange liquid flows in the serpentine tube 4 and exchanges heat with the outer cylindrical surface of the battery cell 1 through the tube wall of the serpentine tube 4 . There are two brackets 5 for each battery module, and two bolt holes are reserved at the left and right ends of the bottom of each bracket 5 for fixing the battery module on the beams on both sides of the lower tray 100 .

It should be noted that for the power battery system of the present invention, in terms of specific implementation, three battery modules with different structures can be used, which are respectively located at the front, middle and rear positions of the power battery system. All modules are connected in parallel by liquid pipes. .

In the present invention, as shown in Fig. 8 to Fig. 10, the end pipe 3 is composed of a main pipe 300, a main pipe head 301, a plug 302 and a branch pipe 303, wherein the plug 303 is welded to the main pipe 300 or Bonding together, the main pipe head 301 is welded with the main pipe 300 , and the branch pipe 303 is welded with the main pipe 300 .

In the present invention, in terms of specific implementation, as shown in FIG. 11 , the serpentine tube 4 includes a hollow middle branch pipe 400 , and the outside of the middle branch pipe 100 is wrapped with a heat-conducting glue 401 .

It should be noted that, for the power battery system provided by the present invention, a cylindrical cell and battery modules of three sizes are used. The modules have the same structure and are located at the front, middle, and rear of the system. There is a serpentine tube for the thermal management of the battery cells. The internal thermal management pipelines of all modules are connected in parallel to ensure the rapid, efficient and temperature uniformity of the thermal management of all the battery cells.

In the present invention, in terms of specific implementation, see Fig. 4 to Fig. 6, for the present invention, when the battery module is assembled, the battery cell 1 is positioned in the cylindrical hole of the support 5, and the support 5 is usually made of insulating material (such as engineering Plastic injection molded parts), using the pipe branch 303 shown in Figures 9 to 10 to be plugged into the intermediate branch pipes 401 in Figure 11, and then welded to form an integral part of the thermal management structure of a battery module shown in Figure 7.

The thermal management structure of the battery module shown in Figure 4 is inserted as a whole between the cells 1 shown in Figure 4 and Figure 6, and another bracket 5 is buckled in the perspective direction at the position shown in Figure 1 (hidden in the figure) ), and finally on the outside of the bracket 5, traditional methods such as nickel sheets can be used to connect the cylindrical batteries in series and parallel. In the individual holes on the bracket 5, bolts can be used instead of the batteries to connect the brackets located on the front and rear sides of the battery 1 5. At this point, the assembly of a battery module is completed.

In the present invention, in terms of specific implementation, the left and right sides of the bracket 5 respectively have a main pipe 6;

A plurality of joints 2 located at the left and right ends of the bracket 5 communicate with adjacent main pipelines 6 respectively.

Specifically, the upper and lower pallets 100 include a whole base plate composed of a plurality of base plates 16 (adjacent base plates 16 can be welded together, and the base plate 16 is fixedly connected by welding with the beam and the longitudinal beam respectively);

The overall rear end edge of the bottom plate is fixed (for example welded) with a transversely distributed main pipe beam 7;

A plurality of longitudinal beams 14 are fixedly arranged on the left and right edges of the bottom plate as a whole;

A crossbeam 13 is fixedly arranged at the middle part and the front end of the bottom plate as a whole.

In terms of specific implementation, the side of the main pipe beam 7 located at the rear end of the lower tray 100 is installed with a heat management main joint 8;

The thermal management main joint 8 communicates with the main pipeline 6 .

It should be noted that the thermal management main joint 8 has two ports, respectively serving as a liquid inlet and a liquid outlet, for flowing in and out of the heat exchange liquid for heating or cooling. The heat exchange liquid can be flame-retardant cooling liquid, or other existing heat exchange liquids used in battery modules.

In terms of specific implementation, the two interfaces of the thermal management main joint 8 can communicate with the liquid outlet and the liquid inlet of a water pump through a hollow connecting pipe respectively. The main pipe 6, the thermal management main joint 8 and the connection The pipes are pre-filled with heat exchange liquid. Among them, the role of the water pump is to provide circulating power for the cooling liquid in the water pipe 1 and the connecting pipe, thereby ensuring that the heat exchange liquid can flow in the main pipe 6, the heat management main joint 8 and the connecting pipe, and can control the flow of the heat exchange liquid flow speed. In terms of specific implementation, the water pump can be an existing commonly used cooling pump, for example, it can be the same as a commonly used cooling pump on a general automobile.

In terms of specific implementation, the side of the main pipe beam 7 located at the rear end of the lower tray 100 is also installed with a high-voltage device 17, a total positive and negative connector (ie, a charging and discharging connector) 9 and a communication connector 10;

The high-voltage device 17 is conductively connected with the total positive and negative joints 9 .

In specific implementation, the top of the battery module 200 is installed with a series row 18 .

Fig. 12 is an assembly diagram of the thermal management structure of the power battery system provided by the present invention. The main pipeline 6 for entering and exiting the cooling liquid or heating liquid of the power battery system is used to connect the liquid management systems of all modules in parallel. The whole system Each serpentine tube 4 is connected in parallel to the main pipe 6 through each joint 2, the main pipe 6 is connected to the main pipe beam 7, the liquid used for heat exchange circulates inside the main pipe beam 7, and there is an intermediate isolation at the main joint 8, the main joint 8 The liquid enters and exits once to realize the heat exchange between the Pack system and the whole vehicle.

Fig. 13 is an assembly diagram of the lower tray and lifting lugs of the power battery system of the present invention. Before installing the module in the system, the lower tray 100 is first assembled. The main load-bearing parts of the system are mainly composed of the main pipe beam 7, the heat management main joint 8, the main positive and main negative joints (that is, the charging and discharging joints) 9, the communication joints 10, the first lifting lug 11 of the C type, and the second lifting lug of the Z type. Hanging lug 12, beam 13, longitudinal beam 14, connecting bolt 15 and base plate 16 constitute.

Fig. 2 and Fig. 3 are the assembly drawing and the top view of the system assembly of the power battery system of the present invention respectively. A high-voltage device 17 is installed at the back end of the system, and a series row 18 is installed above the module. The total positive and negative terminals of the battery are connected to the high-voltage device 17. The car needs to be installed in the back end of the system.

In the present invention, in terms of specific implementation, the exterior of the plurality of battery modules 200 is covered with an upper cover 19 .

In the present invention, in terms of specific implementation, a plurality of second lifting lugs 12 are welded at intervals on the longitudinal beam 14;

The left and right ends of the rear side of the main pipe beam 7 are respectively welded with a first lifting lug 11 .

Fig. 1 is an overall assembly structure diagram of the power battery system mentioned in the present invention. On the basis of Figures 7 and 8, fasten the upper cover 19, the entire battery system is mechanically connected to the chassis frame of the vehicle through the bolts 15 on the lifting lugs, and the thermal management joint 8 is connected to the thermal management system of the new energy vehicle , realize battery thermal management control through liquid heat exchange; the total positive and negative output joint 9 is connected with the motor controller and charger of the new energy vehicle to realize battery discharge and charging; the communication joint 10 is connected with the vehicle controller of the new energy vehicle Connect to realize CAN bus communication control.

In the present invention, in terms of specific implementation, the present invention is a parallel thermal management system, which greatly improves the thermal management efficiency and is beneficial to reduce the temperature difference of the battery core. After simulation, the initial temperature of the battery system is 32°C, charged at a rate of 0.5C, the inlet liquid temperature of each module is 25°C, the flow rate is 0.3m/s, and the inlet diameter is 10mm, that is, the flow rate of the module is 1.4L/min and the system Under the initial condition of the flow rate of 23.8L/min, after 18 minutes of simulation, the battery temperature drops to about 26°C, the temperature difference of the battery cells in the module is controlled within 1°C, and the temperature difference of the whole system is controlled within 3°C. The initial temperature of the simulated battery is 32°C, fast charging at 1C rate, using the same liquid flow rate as above, after 20 minutes, the battery temperature drops to about 26°C, the temperature difference of the battery cells in the module is controlled within 3°C, and the temperature difference of the whole system is controlled within 5°C. within ℃. Both working conditions maintain the consistency of the working environment of the battery cell and prolong the working life of the system.

In order to understand the technical solution of the present invention more clearly, it will be described below in conjunction with specific examples.

As shown in Figures 1, 2 and 3, in this embodiment, 4.5Ah-21700 cylindrical batteries are used, and the whole system uses 23 parallel 135 strings, abbreviated as 23P135S. As shown in Figure 4 to Figure 6, each string in the battery module has 25 cylindrical hole positions, of which 23 cylindrical hole positions are used to connect 23 batteries in parallel, and the other 2 positions are used to install built-in bolts for connecting The brackets 5 between the front and rear sides of the battery module are connected together.

In Figure 1 and Figure 2, three types of battery modules, 23P7S modules (9 pieces), 23P3S modules (2 pieces), and 23P11S modules (6 pieces), are arranged at the front, middle and back of the power battery system. The lower trays are connected by bolts on the left and right sides of the bottom of the bracket 5, and a total of eight bolt fixing holes are reserved for the two brackets on the front and rear sides of each battery module. The battery modules are electrically connected in series through the series row 18, and the main pipes 6 for entering and exiting the heat exchange fluid are respectively located on the left and right sides of the power battery system, and are connected to the joints 2 of each battery module, thus forming a complete system. The thermal management system with parallel pipes in the system, the cooling or heating liquid (that is, the heat exchange liquid) flows through each parallel serpentine tube 4, after the simulation, the whole system is charged at a rate of 0.5C, and the temperature difference is within 3°C, and the charge at a rate of 1C, the temperature difference Within 5°C.

In terms of specific implementation, the nominal voltage of a single cell is 3.65V, the capacity is 4.5Ah, the total nominal voltage of the entire power battery system is 135*3.65=492.75V, the total nominal capacity is 4.5*23=103.5Ah, and the total nominal energy is 492.75* 103.5≈51kWh, the weight of the whole system is 359kg (excluding C-type and Z-type lifting lugs), and the nominal energy density of the whole system is 51000/359=142Wh/kg.

In actual assembly, the bottom plate 16 in FIG. 13 can be welded by profile friction stir welding, and the main pipe girder 7, longitudinal beam 14 and cross beam 13 can be welded by profile to form the main load-bearing structure. First install the battery module, thermal management structure and series row, and then install the high voltage and BMS (battery management system) devices. In this embodiment, the high voltage and MS (battery management system) devices are located at the back end of the system, and the specific interface installation location It can be adjusted according to the external requirements of the system.

As shown in FIG. 1 , the upper cover 19 can be formed by punching aluminum plate or SMC, or using carbon fiber mold to reduce weight, and adopts traditional bolt fixing and IP67 sealing. The first lifting lug 11 of the C-type and the second lifting lug 12 of the Z-type are castings or machined parts, and the battery system can be hoisted under the chassis of the new energy vehicle through the connecting bolts 15 .

For the present invention, the entire power battery system can use 4.5Ah 21700 power cells, combined with the full-module parallel thermal management system, because the thermal management is more efficient, and the temperature difference control of the cells is easier, the space structure of the whole system is relatively regular, The main thermal management pipeline is located on the left and right sides. The actual manufacturing and space utilization are more reasonable, and the heat dissipation in the space is relatively uniform. When the temperature difference of the whole system is charged and discharged at a rate of 0.5C, the temperature difference of the whole system can be controlled within 3°C (generally within 6°C). ), so that all cells work in a more identical environment for a long time, and when the external low temperature is -20°C, the liquid in the parallel branch is rapidly heated to ensure that each cell can quickly work above 0°C. That is, the whole-system parallel thermal management system provided by the present invention prolongs the service life of the battery and ensures the safe operation of the whole vehicle for 10 years or 200,000 kilometers. See Table 1 below.

Table 1: Performance parameter table of the power battery system of the present invention in the embodiment.

Therefore, in summary, compared with the prior art, the present invention provides a power battery system based on cylindrical cells, which can reliably and effectively conduct reliable thermal management of the cylindrical battery system, and timely repair the battery cells Cooling and heating treatment, controlling the temperature difference between battery cells, ensuring the temperature uniformity of the battery system, can form an industrial scale, is conducive to wide application, and has great practical significance in production.

The above is only a preferred embodiment of the present invention, and it should be pointed out that for those of ordinary skill in the art, some improvements and modifications can be made without departing from the principle of the present invention. It should be regarded as the protection scope of the present invention.

Claims (10)

1. A power battery system based on a cylindrical battery cell, characterized in that it includes a lower tray (100); A plurality of battery modules (200) are placed on the top of the lower tray (100); Each battery module (200) includes two brackets (5) spaced forward and backward; There are multiple rows of cylindrical holes in each bracket (5) from top to bottom, and a longitudinally distributed cylindrical battery cell (1) is placed in each cylindrical hole contained in each row of cylindrical holes; A serpentine tube (4) is arranged between any two adjacent rows of cylindrical holes; The left and right ends of each bracket (5) respectively have vertically distributed, hollow end pipes (3); The left and right ends of each serpentine pipe (4) are respectively connected with an end pipe (3). 2. The power battery system based on cylindrical cells according to claim 1, characterized in that, the upper or lower part of each end tube (3) is connected to a joint (2). 3. The power battery system based on cylindrical cells according to claim 1, characterized in that, the left and right ends of each serpentine tube (4) are respectively inserted and welded with an end tube (3). 4. The power battery system based on cylindrical cells according to claim 2, characterized in that the joint (2) is in interference fit with the end tube (3). 5. The power battery system based on cylindrical cells according to claim 1, characterized in that, the end pipe (3) consists of a main pipe (300), a main pipe head (301), a plug (302) and a branch pipe (303) ) form, wherein the plug (303) is welded or glued together with the main pipe (300), the main pipe head (301) is welded with the main pipe (300), and the branch head (303) is welded with the main pipe (300). 6. The power battery system based on cylindrical cells according to claim 1, characterized in that, the serpentine tube (4) includes a hollow middle branch pipe (400), and the outside of the middle branch pipe (100) is wrapped with thermally conductive glue (401 ). 7. The power battery system based on cylindrical cells according to claim 1, characterized in that, the left and right sides of the support (5) respectively have a main pipeline (6); A plurality of joints (2) located at the left and right ends of the support (5) communicate with adjacent main pipelines (6) correspondingly. 8. The power battery system based on cylindrical cells according to claim 7, characterized in that, the lower tray (100) comprises a whole bottom plate composed of a plurality of bottom plates (16); The overall rear end edge of the bottom plate is fixedly provided with a transversely distributed main pipe beam (7); A plurality of longitudinal beams (14) are fixedly arranged on the left and right edges of the bottom plate as a whole; The whole middle part and the front end of the bottom plate are fixedly provided with crossbeams (13). 9. The power battery system based on cylindrical cells according to claim 8, characterized in that, a thermal management main joint (8) is installed on the side of the main pipe beam (7) located at the rear end of the lower tray (100); The thermal management main joint (8) communicates with the main pipeline (6); The thermal management header (8) has two interfaces. 10. The power battery system based on cylindrical cells according to claim 1, characterized in that, on the side of the main pipe beam (7) located at the rear end of the lower tray (100), high voltage devices (17), main positive Total negative connector (9) and communication connector (10); The high-voltage device (17) is conductively connected with the total positive and negative joints (9); A series row (18) is installed on the top of the battery module (200); The outer cover of multiple battery modules (200) has an upper cover (19); A plurality of second lifting lugs (12) are welded at intervals on the longitudinal beam (14); The left and right ends of the rear side of the main pipe beam (7) are respectively welded with a first lug (11).