CN212085177U

CN212085177U - Distributed temperature compensation device for battery pack in electric automobile

Info

Publication number: CN212085177U
Application number: CN202021170890.8U
Authority: CN
Inventors: 胡雪婉; 刘姝琦; 徐陈陈; 侯馨云; 乔应; 陈子龙
Original assignee: Xihua University
Current assignee: Sichuan Xihua Automobile Technology Service Co ltd
Priority date: 2020-06-22
Filing date: 2020-06-22
Publication date: 2020-12-04
Anticipated expiration: 2030-06-22

Abstract

The utility model particularly relates to a distributed temperature compensation device for battery pack in electric automobile, the compensation device and the original cooling liquid type heat dissipation system of battery pack are installed on the battery pack bracket of electric automobile together, the compensation device comprises a plurality of Peltier elements arranged between the battery pack and the upper cover, the cold end surface of the Peltier element is contacted with the upper surface of the monomer battery arranged below the Peltier element, and the hot end surface of the Peltier element is clung to the lower surface of the heat conduction frame; after the temperature compensation is carried out by the temperature compensation device, one or more single batteries with too low temperature in the battery pack can be rapidly heated in an auxiliary manner, so that the problem of too high temperature of the single batteries is effectively avoided, and the safety of the battery pack is improved; meanwhile, the heat of the single battery with overhigh temperature can be transferred to the single battery with lower temperature, so that the temperature difference among the single batteries in the battery pack is reduced, and the performance of the battery is improved.

Description

Distributed temperature compensation device for battery pack in electric automobile

Technical Field

The utility model relates to an electric automobile group battery temperature control field, in particular to distributing type temperature compensation device is used to group battery among electric automobile.

Background

Batteries of the new energy automobile are the more key parts of the new energy automobile, the quality of the batteries of the new energy automobile is related to the overall performance of the new energy automobile, once the batteries of the new energy automobile have certain hidden dangers, accidents can be caused, and therefore, corresponding safety design is required to be carried out on some parts of the batteries of the new energy automobile, which may have the hidden dangers.

From the performance point of view, the starting point of the temperature control of the power battery is to keep the power battery in a good working state all the time. Generally, too low battery temperature affects the charge and discharge capacity of the battery, and too high temperature affects the life and safety of the battery. That is, the electric vehicle is expected to ensure that the power battery works in a temperature range of 20-55 ℃ in normal running, charging and discharging and standby states so as to exert the maximum performance of the power battery and prolong the endurance mileage of the electric vehicle as far as possible.

In cold regions or winter, in order to reach the working temperature range of the power battery as soon as possible, an electric heating device is generally arranged on an existing electric vehicle, but the existing heating mode is to heat the whole battery pack, or the battery pack is divided into several modules, an average value obtained after the temperature of a plurality of batteries in the modules is collected is heated, if the temperature rise of the plurality of single batteries in the battery pack after heating is the same, the temperature of the plurality of single batteries can be ensured to be close, but if the temperature of a certain single battery is too low due to faults or other reasons, an electric heating system is difficult to control the temperature of the single battery, or an effective method for performing balanced control on the heat dissipation capacity of the plurality of single batteries does not exist. The temperature rise control of the single battery can not be realized, so that the temperature rise heating effect of the power battery pack is not good, and the use effect is reduced.

Disclosure of Invention

To the problem, the utility model aims at providing a distributed temperature compensation device for group battery among the electric automobile that intensification is balanced, intensification is effectual.

In order to achieve the purpose of the invention, the technical scheme adopted by the utility model is as follows: the distributed temperature compensation device for the battery pack in the electric automobile is arranged on a battery pack bracket of the electric automobile, the battery pack bracket is of a box type framework structure formed by welding or connecting a plurality of steel pipes by bolts, and the battery pack bracket is internally provided with the battery pack formed by a plurality of vertically placed cylindrical single batteries;

the compensation device comprises a plurality of Peltier elements arranged between the battery pack and the upper cover, the number of the Peltier elements is consistent with that of the single batteries, and the cold end face of each Peltier element is in contact with the upper surface of the single battery arranged below the Peltier element and leaves the positive lead of the upper surface of the single battery; the hot end face of the Peltier element is tightly attached to the lower surface of the heat conducting frame in a sticking or buckling connection or clamping manner; the heat conducting frame is a # -shaped flat frame consisting of a plurality of metal heat conducting strips which are arranged in a staggered manner transversely and longitudinally, each Peltier element is positioned right below a # -shaped grid intersection point, and flange flanges arranged on the periphery of the heat conducting frame are connected with the upper cover through bolts;

the power supply lead of the Peltier element is led out from the side surface of the Peltier element and then is connected with the power supply line of the auxiliary battery through the relay switch; a temperature sensor is stuck on the outer side surface or the lower bottom surface of the upper part of the single battery, the signal output end of the temperature sensor is connected with the signal input port of the microcomputer, and the signal control end of the relay switch is connected with the signal output port of the microcomputer; the power cord of the microcomputer is connected with the auxiliary battery, and the auxiliary battery and the microcomputer are installed on the battery pack bracket or the bottom plate through bolts or buckles.

The material of heat conduction frame be the copper, the Peltier element be the cylinder, the lower bottom surface of cylinder is the cold junction face, cold end face and monomer battery's up end contact, set up first ring channel on the lower bottom surface of cylinder, first ring channel suits with monomer battery's external diameter size, the wire guide of falling L shape is seted up to first ring channel bottom, the other end of wire guide is worn out from the lateral wall of cylinder, the wire penetrates the wire in the wire guide, the wire is worn out from the wire guide and is connected with relay switch, auxiliary battery in proper order.

Drawings

FIG. 1 is a schematic diagram of a Peltier element temperature rise;

FIG. 2 is a schematic diagram of a conventional electrically heated temperature raising system;

FIG. 3 is a schematic view of a battery pack stand;

FIG. 4 is a schematic diagram of the connection of a single cell to a Peltier element;

FIG. 5 is a schematic diagram of a microcomputer control circuit;

FIG. 6 is a diagram of a thermal frame bottom mounting 8x8 Peltier elements;

FIG. 7 is a schematic diagram of a 74HC595 chip expansion control bit circuit;

FIG. 8 is a schematic view of a heat-conducting frame;

FIG. 9 is a flow chart of a method of temperature compensation;

FIG. 10 is a schematic diagram of marking the center node and the first node in step c of the temperature compensation method;

FIG. 11 is a schematic diagram of the method for temperature compensation in step d;

fig. 12 is a schematic diagram illustrating the step e of the temperature compensation method for finding the shortest path from the central node to the destination;

FIG. 13 is a schematic diagram of the third node according to FIG. 12;

FIG. 14 is a diagram illustrating a fourth node labeled in step f of the temperature compensation method.

Detailed Description

As shown in fig. 3-8, the distributed temperature compensation device for the battery pack in the electric vehicle is mounted on the battery pack bracket of the electric vehicle or on the bottom plate of the vehicle chassis;

the battery pack bracket is a hollow box type framework structure formed by welding or bolting a plurality of steel pipes, and can also be formed by splicing a plurality of rectangular steel pipes; the battery pack support is internally provided with a plurality of vertically-arranged cylindrical single batteries, the plurality of single batteries are arranged side by side to form a rectangular, square or polygonal battery pack, the battery pack is arranged on a bottom plate 1, the bottom plate 1 is welded or bolted with a bottom frame of the battery pack support, and the battery pack support is connected with a cross beam or a longitudinal beam of a body framework of an electric automobile through bolts; the upper surface of the bottom plate 1 can be provided with a groove which is adaptive to the shape of the battery pack, the battery pack is clamped in the groove, or the upper surface of the bottom plate 1 is welded or bolted with a plurality of flange plates with flange holes, and the battery pack is placed in the flange plates; or a plurality of single batteries are bound into a row by using metal strips, and the metal strips are connected with corresponding clamping grooves arranged on the upper surface of the bottom plate 1 through buckles, so that the battery pack is fixed on the bottom plate;

the bottom plate 1 is a rectangular or square flat plate with a certain thickness, a box-shaped upper cover 21 with an opening is sleeved above the battery pack, and flange plates are arranged on the periphery of the upper cover 21 and are connected with the battery pack bracket or the bottom plate 1 through bolts; an annular groove is arranged on the lower end face of the upper cover 21, a sealing ring is clamped in the groove, and the lower part of the sealing ring is in contact with a sealing groove arranged at a corresponding position on the bottom plate 1, so that the upper cover 21 and the bottom plate 1 can form a closed space, and the waterproof and dustproof effects are achieved;

the compensation device comprises a plurality of Peltier elements 30 arranged between the battery pack and the upper cover 21, the working principle of the Peltier elements 30 is shown in figure 2, the Peltier elements are generally in a flat plate shape, two surfaces of the Peltier elements are respectively a cold end or a hot end, an N pole/P pole and a connecting lead are arranged in an interlayer in the middle of the flat plate, when the lead is electrified, the cold end absorbs heat, the hot end releases heat, and when current in the lead reversely flows, the positions of the cold end and the hot end are interchanged; the peltier element adopted in the application can be a type TEC1-12712, a type TEC1-12707, a type DA-12-110-01, or other common peltier element types.

The number of the peltier elements 30 is the same as the number of the single cells, and as shown in fig. 4, the cold end surface of the peltier element 30 contacts the upper surface of the single cell placed therebelow and leaves the positive lead of the upper surface of the single cell; the hot end face of the Peltier element 30 is tightly attached to the lower surface of the heat conducting frame 34 in a sticking or buckling connection or clamping manner;

as shown in fig. 9, the heat conducting frame 34 is a cross-shaped flat frame composed of a plurality of metal heat conducting strips arranged in a staggered manner in the horizontal and vertical directions, each peltier element 30 is located right below the intersection point of the cross-shaped grid, and flange flanges arranged around the heat conducting frame 34 are connected with the upper cover 21 by bolts;

the heat conducting frame 34 is made of a copper plate, a magnesium-copper alloy plate or a magnesium-aluminum alloy plate, the peltier element 30 is a cylinder, the lower bottom surface of the cylinder is a cold end surface, the cold end surface is in contact with the upper end surface of the single battery 12, a first annular groove is formed in the lower bottom surface of the cylinder and is matched with the outer diameter of the single battery 12, an inverted-L-shaped lead hole is formed in the bottom of the first annular groove, the other end of the lead hole penetrates out of the side wall of the cylinder, a lead penetrates into the lead hole, and the lead penetrates out of the lead hole and is sequentially connected with the relay switch and the auxiliary battery 11; the upper end surface of the cylinder is a hot end surface, and the hot end surface is contacted with the bottom surface of the ring groove arranged at the corresponding position on the lower bottom surface of the heat conducting frame 34;

the power supply lead of the peltier element 30 is led out from the side thereof and then connected to the power supply line of the auxiliary battery 11 through the relay switch 31; the auxiliary battery 11 can be independently arranged in the battery pack bracket, or can be formed by directly connecting a plurality of single batteries in the battery pack in series or in parallel; a temperature sensor 32 is stuck on the outer side surface or the lower bottom surface of the upper part of the single battery, the signal output end of the temperature sensor 32 is connected with the signal input port of the microcomputer 33, and the signal control end of the relay switch 31 is connected with the signal output port of the microcomputer 33; the power cord of the microcomputer 33 is connected with the auxiliary battery 11, and the auxiliary battery 11 and the microcomputer 33 are mounted on the battery pack bracket or the base plate 1 through bolts or buckles.

The temperature sensor can be a naked paster PT1000 temperature sensor, an imported paster DS18b20 digital temperature sensor probe, or paster temperature sensors of other types or buckle temperature sensors;

the microcomputer 33 can be STM32F100ZC 112GPIO singlechip or AT89C52 singlechip or other singlechips, or can be PLC industrial control machine of Mitsubishi corporation, or can be other microcomputers with complete control function; when the number of the single batteries is large, a single chip microcomputer with matched number of I/O ports can be used, or a serial-to-parallel mode can be used to increase control pins, as shown in FIG. 7, a groove is arranged on the lower bottom surface of the heat conduction frame, Peltier elements are placed in the groove, 64 Peltier elements with 8x8 in total are arranged, three 74HC595 chips can be used to control corresponding to 64 single batteries, as shown in FIG. 8, three 74HC595 chips are connected in series, serial DATA is input through a DATA pin of U45, a SQH pin of U45 is connected to a DATA pin of U46, a SQH pin of U46 is connected to a DATA pin of U47, so that 24-bit serial DATA is input through U45 and then latched, the 3-byte values can be respectively output through U45, U46 and U47, expansion of the pins is realized, and only a circuit of the single chip microcomputer which can be used when a plurality of Peltier elements are controlled is taken as an example, other common expansion methods can also be used, and the expansion method of the circuit pins is not limited herein.

According to the distributed temperature compensation device for the battery pack in the electric vehicle, the method for performing temperature compensation comprises the following steps: after the battery pack starts to operate, the coolant-type heat dissipation system starts to operate, and the microcomputer 33 performs battery pack temperature compensation according to the following steps:

the first embodiment is as follows: using the heat conducting frame with 8 × 8 peltier elements shown in fig. 7, 64 loose 18650 lithium battery cells are placed in corresponding positions below the heat conducting frame to form a battery pack, and common temperatures of the lithium battery include charging temperature: 0-45 ℃, discharge temperature: -20 ℃ to 60 ℃, temperature protection: 70 +/-5 ℃, the normal working temperature area of the single battery is 20-60 ℃, the normal working temperature area is a low-efficiency working area at 10-20 ℃, the low-efficiency working area at 0-10 ℃, the ultra-low-efficiency working area at-10-0 ℃, and the lowest temperature critical value which can be borne by the battery at-20 ℃.

Step a: the peltier elements 30 above each cell 12 are numbered according to their position in the grid of the heat conducting frame 34, and then the respective temperatures of all the cells 12 in the battery are collected in real time by the temperature sensors 32 and are sequentially noted as T1, T2. . . Tn; finding out the maximum value and the minimum value in T1-Tn, and marking as T _ max and T _ min; the microcomputer 33 also stores a temperature upper limit value T _ H and a temperature lower limit value T _ D when the battery normally operates; where T _ H is 75 ℃ and T _ D is-20 ℃, and then the following steps are followed:

step b: the value of T _ min is determined as follows:

if T _ max is within the first temperature range T01, indicating that the battery pack 11 is operating normally, returning to step a; t01 was set here (20 ℃, 60 ℃),

this indicates that the temperature of each single battery in the battery pack is greater than 20 ℃, and the battery pack can be considered to be in a normal state;

if T _ min exceeds the first temperature range T01 and is within the second temperature range T02, go to step c; t02 is set here (10 ℃, 20 ℃)

If T _ min exceeds the second temperature range T02 and is within the third temperature range T03, go to step d; t03 is set here (0 ℃, 10 ℃)

If T _ min exceeds the third temperature range T03 and is less than T _ H, namely is positioned at (-10 ℃, 0 ℃), entering step e;

if T _ min is smaller than T _ D, entering step f;

step c: as shown in fig. 10, as can be seen from the operating temperature range of the loose battery, the temperature of the cell corresponding to T _ min at this time is between (10 ℃, 20 ℃), which indicates that the cell is not sufficiently preheated, so that in addition to the starting of the conventional integral temperature raising device of the electric vehicle, the microcomputer 33 also controls the peltier element 30 at the node position where T _ max is located to be electrically heated, so as to heat the cell 12 corresponding to T _ min, and after a certain time, if T _ max is within the first temperature range T01, that is, greater than 20 ℃, the step a is returned, otherwise, the step d is entered;

step d: as shown in fig. 11, it can be known from the operating temperature interval of the loose battery that the temperature of the unit battery corresponding to T _ min is between (0 ℃, 10 ℃), and a better auxiliary temperature raising measure needs to be performed on the unit battery, a node where the unit battery 12 corresponding to T _ min is located is taken as a central node, a node corresponding to a node whose periphery is directly connected with a central point through a grid in a shape like a Chinese character jing is marked as a first node, a node whose periphery is directly connected with the first node through the grid in a shape like a Chinese character jing is marked as a second node, if the node is marked as the central node or the first node, the second node is not marked, a plurality of peltier elements 30 corresponding to the central node, the first node and the second node are electrified and heated, so that the plurality of peltier elements around T _ min can be started, and the heat generated by the unit battery around T _ min can be quickly concentrated to T _ min, after a certain time, if T _ min is within T02, the temperature rising measure is effective, and the step c is returned, so that the starting number of the Peltier elements can be reduced, and the electric energy can be saved; if the temperature of T _ min is not obviously increased, which indicates that the temperature of the single battery is still too low, and a more powerful cooling measure needs to be taken, entering step e;

step e: as shown in fig. 12 and 13, the node position where the cell 12 with the highest temperature is located in all the remaining unmarked nodes marked in step d is marked as an end point, the temperature of the end point is T _ max in the remaining unmarked nodes, the shortest path from the start point to the end point is calculated with the center node as the start point, then all the unmarked nodes corresponding to the shortest path are marked as a third node, and the peltier elements 30 at the center node, the first node, the second node, the third node and the end point are heated by energization; therefore, when more Peltier elements are controlled to assist in temperature rise, the single batteries with the lowest temperature and the single batteries with higher temperature are used as a temperature rise path, the temperature difference among the single batteries can be adjusted, the temperature of each single battery is closer, the temperature consistency of each single battery in the battery pack can be greatly improved, and the positive influence on the voltage stability, the discharge efficiency of the battery, the cycle life and the like is realized;

if the T _ min is in the third temperature range T03 after a certain time, the temperature rising measure achieves the preset effect, the step d is returned to save energy, if the temperature still exceeds T03, the current temperature rising measure still cannot effectively control the single battery, and the step f is carried out;

step f: as shown in fig. 14, of all the remaining unmarked nodes, all nodes with temperature range of T _ max-T _00, T _ max are found, and the nodes meeting the requirements are marked as auxiliary end point 1 and auxiliary end point 2. . . An auxiliary end point n;

calculating a plurality of ring shortest paths from the central node to all auxiliary end points and end points, marking one ring shortest path with the largest number of unmarked nodes in the plurality of ring shortest paths as an optimal path, and marking all unmarked nodes in the optimal path as fourth nodes; the peltier elements 30 at the center node, the first node, the second node, the third node, and the fourth node are electrically heated;

if the temperature is within the range from T _ min to a third temperature range T03 after a certain time, returning to the step e, otherwise, entering the step g;

step g: the power of a plurality of single batteries corresponding to the central node and the first node is cut off, other single batteries are used for continuing working, the position of the central node is recorded by the microcomputer 33 and an alarm signal is generated, the alarm signal and the position of the central node are displayed by a display screen in communication connection with the microcomputer 33, a driver is reminded of the single batteries with too low temperature in the battery pack, and therefore the overall temperature stability and safety of the battery pack are effectively protected.

After the temperature compensation is carried out by the temperature compensation device, one or more single batteries with over-high temperature in the battery pack can be quickly heated in an auxiliary manner, the problem of over-low temperature of the single batteries is effectively avoided, and the performance and the using effect of the battery pack are improved; meanwhile, the heat of the single battery with overhigh temperature can be transferred to the single battery with lower temperature, so that the temperature difference among the single batteries in the battery pack is reduced, and the performance of the battery is improved.

Example two: as shown in fig. 12, in the step e, if there is more than one shortest path, calculating the average temperature of all the third nodes in each shortest path in the plurality of shortest paths, selecting the path with the lowest average temperature as the shortest path, and heating the peltier elements 30 at all the nodes corresponding to the shortest path by applying electricity; this may achieve a faster cooling effect.

Example three: and when the battery pack has the single batteries isolated by power failure, the remaining single batteries can continue to repeat the steps from the step a to the step g, and when the shortest path is searched in the steps from the step e and the step f, the isolated single batteries are used as obstacles, and a labyrinth treasure searching type calculation mode is carried out from the starting point to the end point to calculate the shortest path, wherein the search can be carried out by adopting an algorithm A, the algorithm A + can also be adopted, and other common two-dimensional plane labyrinth treasure searching type algorithms can also be adopted for calculation.

Claims

1. The distributed temperature compensation device for the battery pack in the electric automobile is arranged on a battery pack bracket of the electric automobile, the battery pack bracket is of a box type framework structure formed by welding or connecting a plurality of steel pipes by bolts, and the battery pack bracket is internally provided with the battery pack formed by a plurality of vertically placed cylindrical single batteries;

the method is characterized in that: the compensation device comprises a plurality of Peltier elements (30) arranged between the battery pack and an upper cover (21), the number of the Peltier elements (30) is the same as that of the single batteries, and the cold end face of each Peltier element (30) is in contact with the upper surface of the single battery arranged below the Peltier element and leaves the upper surface of the single battery from a positive lead; the hot end face of the Peltier element (30) is clung to the lower surface of the heat conduction frame (34) in a sticking or buckling connection or clamping manner; the heat conduction frame (34) is a # -shaped flat frame consisting of a plurality of metal heat conduction strips which are arranged in a staggered mode in the transverse and longitudinal directions, each Peltier element (30) is located right below a # -shaped grid intersection point, and flange flanges arranged on the periphery of the heat conduction frame (34) are connected with the upper cover (21) through bolts;

the power supply lead of the Peltier element (30) is led out from the side surface and then is connected with the power supply line of the auxiliary battery (11) through a relay switch (31); a temperature sensor (32) is stuck on the outer side surface or the lower bottom surface of the upper part of the single battery, the signal output end of the temperature sensor (32) is connected with the signal input port of the microcomputer (33), and the signal control end of the relay switch (31) is connected with the signal output port of the microcomputer (33); a power line of the microcomputer (33) is connected with the auxiliary battery (11), and the auxiliary battery (11) and the microcomputer (33) are installed on the battery pack bracket or the bottom plate (1) through bolts or buckles;

the material of heat conduction frame (34) be the copper, Peltier element (30) be the cylinder, the lower bottom surface of cylinder is the cold junction face, the last terminal surface contact of cold terminal surface and battery cell (12), set up first ring channel on the lower bottom surface of cylinder, the external diameter size of first ring channel and battery cell (12) suits, the wire guide of falling L shape is seted up to first ring channel bottom, the other end of wire guide is worn out from the lateral wall of cylinder, the downthehole wire that penetrates of wire, the wire follow the wire guide wear out after in proper order with relay switch, auxiliary battery (11) are connected.