Insulated battery pack and thermal management method

Abstract

The present invention discloses a heat-insulated battery pack, which includes a battery module containing a plurality of rows of battery cells and a heat-insulating member. Two heat-insulating layers are provided on the heat-insulating member. The plurality of rows of battery cells are all installed in one heat-insulating layer. The two heat-insulating layers are installed opposite to each other, and a hollow chamber is installed between the two heat-insulating layers. The hollow chamber is filled with gas to form an air layer, which suppresses heat conduction on both opposite sides of the air layer.

Description

Technical Field

[0001] The present invention claims priority based on a Chinese patent application filed with the China National Intellectual Property Administration on December 30, 2022, with an application number of 202211721974.X, and a Chinese patent application filed with the China National Intellectual Property Administration on December 30, 2022, with an application number of 202223608141.0, and incorporates all the contents of the above Chinese patent applications by reference into the present invention. The present invention relates to the field of batteries, and particularly to a heat-insulating battery pack and a thermal management method.

Background Art

[0002] A battery pack is formed by a plurality of battery modules, and a battery management system, an electrical system, etc. are further installed. Battery thermal management is one of the important functions in the battery management system, and mainly aims to always keep the battery modules operating within an appropriate temperature range, which is to maintain the battery modules in an optimal operating state. The thermal management of the battery mainly includes functions such as cooling, heating, and temperature equalization. The cooling and heating functions are mainly adjusted according to the influence that the external environmental temperature can exert on the battery. Temperature equalization is to reduce the temperature difference within the battery modules and prevent rapid degradation due to overheating of some batteries.

[0003] In the conventional battery pack, due to the spatial constraints of the battery box body, it is difficult to take effective heat-insulating measures for the battery pack. When the temperature of the external environment is low, heat is supplied to the battery pack through the battery thermal management of the battery management system, but the problem of rapid heat loss due to the heat-insulating performance of the battery pack occurs.

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to solve at least one drawback existing in the above prior art, the present invention provides a heat-insulating battery pack that solves the problem of rapid heat loss of the conventional battery pack and improves the heat-insulating performance of the battery pack.

Means for Solving the Problems

[0005] In a first aspect, the present invention provides a heat-retaining battery pack. A battery pack containing multiple rows of battery cells, The device includes two heat-insulating layers, each of which is placed on one of the heat-insulating layers, the two heat-insulating layers facing each other, a hollow chamber between the two heat-insulating layers, the hollow chamber being filled with gas to form an air layer, and a heat-insulating member that suppresses heat conduction on both sides of the air layer facing each other.

[0006] In one embodiment, the heat-insulating member is further provided with a plurality of positioning openings. The shape and dimensions of each positioning opening are to match the shape and dimensions of each battery cell. Each battery cell is mounted and fixed inside the positioning opening.

[0007] In one embodiment, a heat-insulating ring is installed on the inner wall of each positioning opening. The heat-insulating ring abuts against the end face of the corresponding battery cell.

[0008] In one embodiment, the heat-retaining battery pack further includes at least one liquid cooling plate. The at least one liquid cooling plate is thermally connected to the battery pack.

[0009] In one embodiment, the multiple liquid cooling plates are all distributed perpendicularly to the heat-insulating member. Each liquid cooling plate is installed between two adjacent rows of battery cells. The multiple liquid cooling plates are connected in parallel by liquid cooling pipes.

[0010] In one embodiment, the battery cell is a cylindrical cell. Multiple rows of the battery cells are arranged alternately. Each of the liquid cooling plates is installed in a corrugated manner so that the peripheral surface of each battery cell is bonded to the liquid cooling plate.

[0011] In one embodiment, the heat-insulating battery pack further includes a pallet. The heat-insulating member is installed on the pallet.

[0012] In one embodiment, the heat-insulating battery pack further includes a battery box. The battery pack, the heat-insulating member, the pallet, and each of the liquid cooling plates are all mounted and fixed inside the battery box.

[0013] In one embodiment, the pallet is provided with a plurality of pressure release ports. Each of the battery cells is installed corresponding to each of the pressure release ports. A pressure release passage is provided between the pallet and the battery box. The inner holes of the heat retention ring, the pressure release ports, and the pressure release passage are sequentially connected to guide the discharge of the hot gas flow generated in the battery cells during thermal runaway to the outside of the battery box.

[0014] In one embodiment, the battery box includes a bottom protective plate and a U-shaped outer frame. A first stage, a second stage, and a third stage are installed on the inner wall of the outer frame. The first stage, the second stage, and the third stage are installed sequentially along the height direction of the outer frame, starting from one large surface of the outer frame. The bottom protective plate is fixed to the first stage. The pallet is fixed to the third stage.

[0015] In one embodiment, the pressure relief passage includes a first pressure relief chamber and a second pressure relief chamber. The first pressure relief chamber is formed between the pallet, the bottom protective plate, and the inner wall of the second tier. The second pressure relief chamber is installed inside the outer frame. The first pressure relief chamber is electrically connected to the second pressure relief chamber.

[0016] In one embodiment, a temperature-controlled battery chamber is formed by the heat-insulating member and the inner wall of the outer frame. The battery pack is located inside the temperature-controlled battery chamber.

[0017] In a second aspect, the present invention provides a thermal management method for use in a battery pack. In this specific method, the measured temperature value of the observed battery is evaluated by comparing it with a preset temperature, and the battery's operating state and heat exchange state are adjusted. The preset temperature includes a first temperature interval, a second temperature interval, a third temperature interval, a fourth temperature interval, and a fifth temperature interval, ranging from low to high temperatures. In the first state, if the measured temperature value is within the first temperature range, the battery is set to a non-charging and non-discharging state, and the battery's heat exchange state is set to a heating state. In the second state, if the measured temperature value is within the second temperature range, the battery's operating state is set to a charging state, and the battery's heat exchange state is set to a heating state. In the third state, if the measured temperature value is within the third temperature range, the battery's operating state is set to either a charging state or a discharging state, and the battery's heat exchange state is set to a heating state. In the fourth state, if the measured temperature value is within the fourth temperature range, the battery is set to either a charging or discharging state, and the battery's heat exchange state is set to a non-heating and non-cooling state. In the fifth state, if the measured temperature value is within the fifth temperature range, the battery's operating state is set to either a charging state or a discharging state, and the battery's heat exchange state is set to a cooling state.

[0018] In one embodiment, the first temperature range is below -20°C, the second temperature range is between -20°C and 5°C, the third temperature range is between 5°C and 15°C, the fourth temperature range is between 15°C and 37°C, and the fifth temperature range is above 37°C.

[0019] In one embodiment, a first termination temperature value is further set within the second temperature interval, and the first state is terminated when the measured temperature value is higher than the first termination temperature value.

[0020] In one embodiment, a second termination temperature value is further set within the third temperature interval, and the second state is terminated when the measured temperature value is higher than the second termination temperature value.

[0021] In one embodiment, a third end temperature value is further set within the fourth temperature range. When the measured temperature value is higher than the third end temperature value, the third state ends.

[0022] In one embodiment, within the fourth temperature range, a fourth end temperature value is further set. When the measured temperature value is lower than the fourth end temperature value, the fifth state ends.

[0023] Summarizing the above, the heat-insulating battery pack and the heat management method according to the present invention have the following technical effects. An air layer is skillfully installed within the heat-insulating member. Due to the gradual heat conductivity of the gas flow, the amount of heat cannot be rapidly conducted to both sides of the air layer, thus avoiding rapid heat loss, ensuring and significantly improving the heat-insulating performance of the battery pack with the heat-insulating member installed, solving the problem of rapid heat loss in the battery pack of the prior art, ensuring that the battery pack can be used within an optimal temperature range over a long period of time, maintaining the optimal usage state, effectively improving the stability of the battery pack, and further effectively improving the reliability of an electrical device (such as an electric vehicle, etc.) using this battery pack.

Brief Description of the Drawings

[0024] [Figure 1] It is a diagram showing the entire first structure of the heat-insulating battery pack according to the first embodiment of the present invention. [Figure 2] It is an overall assembly diagram of the heat-insulating battery pack according to the first embodiment of the present invention. [Figure 3] It is a partially enlarged view of location A in FIG. 2. [Figure 4] It is a partially enlarged view of location B in FIG. 2. [Figure 5] It is a partially enlarged view of location C in FIG. 2. [Figure 6] It is a diagram showing the entire second structure of the heat-insulating battery pack according to the first embodiment of the present invention.

Modes for Carrying Out the Invention

[0025] In the description of this invention, the directions or positional relationships indicated by terms such as "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," and "outside" are directions or positional relationships shown based on the drawings, and are merely for the purpose of facilitating and simplifying the description of this invention. They should not be understood as limitations on this invention, as the specified devices or elements are configured and operated in specific directions or orientations.

[0026] Example 1 In this embodiment, the power battery (lithium-ion power battery) refers to the battery pack 1 and the battery cell 11. The driving range, charging time, and safety of use of the power battery are all limited by the characteristics of the power battery. Furthermore, the characteristics of the power battery are significantly affected by ambient temperature, and in particular, the attenuation of usable energy and power is large in low-temperature environments. Moreover, prolonged use in low-temperature environments accelerates the degradation of the power battery and shortens its service life.

[0027] Conventional power batteries show a significant decrease in capacity and operating voltage at -10°C, and their performance deteriorates even further at -20°C, with a sharp drop in usable discharge capacity, maintaining only about 30% of their specific capacity at room temperature.

[0028] Furthermore, in low-temperature environments, lithium-ion batteries are difficult to charge, and metallic lithium tends to form on the surface of the negative electrode during charging. The growth of lithium dendrites can create holes in the battery separator, causing internal short circuits and permanent damage to the battery. It can also cause thermal runaway, significantly reducing safety during use.

[0029] To address the problem of heat retention in power batteries, the present invention provides a heat-retaining battery pack. Specifically, Figures 1 and 2 clearly show the assembly relationship between the pallet 4 and the heat-retaining member 2 and the battery box 5, and are cross-sectional views of the battery box 5. This heat-retaining battery pack includes the battery box 5, a battery pack 1 installed inside the battery box 5, a heat-retaining member 2, and a pallet 4. The battery pack 1 includes multiple rows of battery cells 11.

[0030] The main principle of this proposed technology is as follows: Two heat-insulating layers 21 are installed in the heat-insulating member 2. Multiple rows of battery cells 11 are each installed in one heat-insulating layer 21. The two heat-insulating layers 21 are installed facing each other, and a hollow chamber is installed between the two heat-insulating layers 21. An air layer 22 is formed in the hollow chamber by filling it with gas. This gas may be air or an inert gas. In this case, the air layer 22 forms a sandwich structure with the two heat-insulating layers 21.

[0031] The stagnant gas inside the hollow chamber and outside the heat-insulating member 2 blocks heat conduction. In other words, the gas inside the hollow chamber has excellent low thermal conductivity, which reduces the rate of heat conduction from the heat-rich heat-insulating layer 21 to the heat-insulating layer 21 with less heat, thus achieving the objective of suppressing heat conduction on both opposing sides of the air layer 22. This improves the heat-insulating effect of the heat-insulating member 2 and enhances its heat-insulating performance.

[0032] Furthermore, the heat-insulating material of heat-insulating member 2 is not limited here, and a material with lower thermal conductivity or higher strength may be selected depending on the operating environment of the battery pack and the needs of the electric vehicle. In addition, the heat-insulating material of heat-insulating member 2 may be placed in different areas according to the heat transfer path to obtain the optimal heat-insulating effect.

[0033] Specifically, as shown in Figures 1 and 2, the battery box 5 includes a bottom protective plate 52 and a curved outer frame 51. If one large surface of the outer frame 51 is defined as a horizontal plane, then the direction perpendicular to the horizontal plane of the outer frame 51 is the height direction of the outer frame 51. On the inner wall of the outer frame 51, a first stage 511, a second stage 512, and a third stage 513 are sequentially installed along the height direction from one side of the horizontal plane. Furthermore, the first stage 511, the second stage 512, and the third stage 513 are all uniformly distributed along the inner circumference of the outer frame 51. The bottom protective plate 52 is embedded inside the outer frame 51 and welded to the first stage 511, making the entire battery box 5 flatter and more robust. In addition, it ensures excellent airtightness of the entire battery box 5.

[0034] Furthermore, as shown in Figures 2, 4, and 5, the pallet 4 is fitted inside the outer frame 51 and welded to the third stage 513 for fixation. The heat-insulating member 2 is installed on the pallet 4, that is, supported on the top of the pallet 4. In this case, the heat-insulating member 2 and the inner wall of the outer frame 51 form the temperature-controlled battery chamber 6. When the box lid is placed over the top of the battery box 5, a relatively sealed space is formed inside the temperature-controlled battery chamber 6.

[0035] If the temperature of the external environment around the battery box 5 is lower than the temperature inside the temperature-controlled battery chamber 6, that is, if the amount of heat inside the temperature-controlled battery chamber 6 is greater than the amount of heat in the external environment around the battery box 5, then the amount of heat in each battery cell 11 of the battery pack 1 is also greater than the amount of heat in the external environment around the battery box 5. Furthermore, since each battery cell 11 is installed in the heat-insulating member 2, the heat from each battery cell 11 is directly conducted to the surface of the battery box 5 and diffused, so heat loss is unlikely.

[0036] Furthermore, when the battery pack is in a low-temperature environment for an extended period, the low conductivity of the air layer 22 allows only a small portion of the heat from the battery cells 11 to be conducted to the surface of the battery box 5 for heat dissipation, thereby improving the battery pack's heat dissipation shortcomings. When the battery pack is in a low-temperature environment for an extended period, the battery management system ensures that the battery pack 1 remains within the optimal temperature range by taking optimal thermal management measures within a sufficient time.

[0037] Similarly, if the temperature of the external environment of the battery box 5 is higher than the temperature inside the temperature-controlled battery chamber 6, that is, if the amount of heat inside the temperature-controlled battery chamber 6 is less than the amount of heat in the external environment of the battery box 5, then the amount of heat in each battery cell 11 of the battery pack 1 is also less than the amount of heat in the external environment of the battery box 5. The heat-insulating material 2 prevents the amount of heat from the external environment from being rapidly transferred to each battery cell 11. Alternatively, if the battery pack is in a high-temperature environment for a long period of time, the battery management system takes optimal thermal management measures within a sufficient time so that the battery pack 1 remains within the optimal temperature range.

[0038] In accordance with the thermal management of the battery management system of the battery pack itself, the temperature inside the temperature-controlled battery chamber 6 and the temperature of each battery cell 11 are both kept in a relatively stable state, ensuring that each battery cell 11 can be used within the optimal temperature range even under external low or high temperature conditions.

[0039] Furthermore, as shown in Figure 3, the heat-insulating member 2 is further provided with a plurality of positioning openings 23. The shape and dimensions of each positioning opening 23 match the shape and dimensions of each battery cell 11. Each battery cell 11 is mounted and fixed inside the positioning opening 23. That is, the end of each battery cell 11 is inserted and connected to the corresponding positioning opening 23. It is preferable that the shape and dimensions of the heat-insulating member 2 match the shape and dimensions of the temperature-controlled battery chamber 6. This restrains and fixes the heat-insulating member 2 inside the temperature-controlled battery chamber 6, that is, the large surface of the bottom of the heat-insulating member 2 abuts against the bottom protective plate 52, and the periphery of the heat-insulating member 2 is uniformly distributed around the periphery of the outer frame 51.

[0040] By cleverly utilizing the rigidity and structural strength of the heat-insulating layer 21, the periphery of each battery cell 11 is uniformly biased and acts on the side wall of the positioning opening 23. Preferably, if the battery cell 11 is a cylindrical cell and the positioning opening 23 is set as a round hole, the periphery of the positioning opening 23 and the side wall of the battery cell 11 are biased toward the central axis of the battery cell 11, that is, the structure of the positioning opening 23 is compatible with the structural strength of the heat-insulating layer 21, effectively ensuring that each battery cell 11 is fixed to the heat-insulating member 2, and exhibiting the unexpected effect of firmly attaching and fixing the battery pack 1 inside the battery box 5.

[0041] During the insertion and assembly process of the ends of the battery cell 11, the bottom surface of the battery cell 11 comes into contact with the pallet 4, and the entire weight of the battery cell 11 is borne by the pallet 4. However, although the battery cell 11 is in direct contact with the pallet 4, the pallet 4 is fixedly connected to the battery box 5. Therefore, some of the heat from the battery cell 11 is transferred along the pallet 4, and ultimately, the heat is conducted from the pallet 4 to the battery box 5, causing a small amount of heat loss from the battery pack.

[0042] In response to the above problems, the present invention further discloses an improved design. Specifically, as shown in Figure 3, a heat-insulating ring 24 is installed on the inner wall of each positioning opening 23, that is, the inner wall of one end of the positioning opening 23 that is close to the pallet 4 extends into the interior of the positioning opening 23 to form the heat-insulating ring 24. The heat-insulating ring 24 is preferably integrally molded with the heat-insulating member 2 and abuts against the end face of the corresponding battery cell 11. The inner diameter of the heat-insulating ring 24 is determined by the battery design or design requirements.

[0043] Each battery cell 11 is inserted and connected into the corresponding positioning port 23 during the mounting process until the end of the battery cell 11 contacts the heat retention ring 24. This prevents collision between the battery cell 11 and the pallet 4 by allowing each battery cell 11 to directly act on the heat retention ring 24. Furthermore, the heat retention ring 24 separates the battery cell 11 from the pallet 4, preventing the direct transfer of heat from the battery cell 11 to the pallet 4 and effectively solving the problem of heat loss from the battery cell 11 along the pallet 4.

[0044] Furthermore, as shown in Figure 3, multiple pressure release ports 41 are installed on the pallet 4, and each battery cell 11 is installed corresponding to each pressure release port 41. Therefore, if thermal runaway occurs in any of the battery cells 11, the high-temperature, high-pressure gas flow generated in the battery cell 11 flows sequentially from the end of the battery cell 11 through the inner holes of the insulation ring 24 and the pressure release ports 41, and finally flows out from the pressure release ports 41.

[0045] As a supplement, the pressure release port 41 is preferably a through hole. In this case, the pressure release port 41 of the pallet 4 is formed by punching, which simplifies the process and reduces costs. The diameter of the through hole is preferably the same as the inner diameter of the insulation ring 24, but it may be larger than the inner diameter of the insulation ring 24. The pressure release port 41 may also be a counterbore or countersunk hole. The inner diameter of the counterbore or countersunk hole is preferably the same as the inner diameter of the insulation ring 24, but it may be larger than the inner diameter of the insulation ring 24. Naturally, the pressure release port 41 may also be a groove structure with a through hole. The diameter of the through hole is greater than or equal to the inner diameter of the insulation ring 24.

[0046] If the dimensions of the pressure release port 41 are larger than the inner diameter of the insulation ring 24, one side of the insulation ring 24 adjacent to the pressure release port 41 can extend into the interior of the pressure release port 41 along the central axis of the insulation ring 24 to form a projection structure (not shown). The shape and dimensions of the projection structure may match the shape and dimensions of the pressure release port 41, or assembly tolerances may be retained between it and the pressure release port 41.

[0047] Specifically, as shown in Figures 3, 4, and 5, a pressure relief passage is provided between the pallet 4 and the battery box 5. The pressure relief passage includes a first pressure relief chamber 531 formed between the pallet 4, the bottom protective plate 52, and the inner wall of the outer frame 51 (i.e., the first pressure relief chamber 531 formed between the pallet 4, the bottom protective plate 52, and the inner wall of the second stage 512), and a second pressure relief chamber 532 installed inside the outer frame 51. The outer frame 51 is further provided with at least one communication port and at least one exhaust port (not shown). The second pressure relief chamber 532 is connected to the first pressure relief chamber 531 by at least one communication port and to the external environment of the battery box 5 by at least one exhaust port.

[0048] Therefore, when any of the battery cells 11 experience thermal runaway, the high-temperature, high-pressure gas (hot gas flow) released from the battery cell 11 flows sequentially through the inner holes of the heat-insulating ring 24 and the pressure release port 41 of the pallet 1, and out into the first pressure release chamber 531. The high-temperature, high-pressure gas is then guided by the first pressure release chamber 531 to flow into the second pressure release chamber 532 via the communication port, and finally flows in a constant direction along the second pressure release chamber 532 to the exhaust port and is discharged to the outside of the battery box 5. This has the effect of guiding the hot gas flow generated from the battery cell 11 in a thermal runaway state and sequentially discharging it to the outside of the battery box 5.

[0049] Unexpectedly, by combining the heat-insulating ring 24 of the heat-insulating member 2, the pressure release port 41 of the pallet 4, the second pressure release chamber 532 of the outer frame 51, and the first pressure release chamber 531 installed between the bottom protective plate 52 and the pallet 4, the high-temperature, high-pressure gas is directly discharged into the temperature-controlled battery chamber 6 without diffusion, thereby reducing and even avoiding the impact of the high-temperature, high-pressure gas flow on other battery cells 11 of the battery pack 1. This avoids the problem of the hot gas flow generated when any of the battery cells 11 of the battery pack 1 experience thermal runaway diffusing irregularly into the temperature-controlled battery chamber 6 and causing thermal diffusion, thereby reducing the impact of thermal runaway on the battery pack 1 and improving the stability of the battery pack during use.

[0050] If a battery cell 11 or battery pack 1 experiences thermal runaway, or if a battery cell 11 is overcharged or over-discharged, the temperature of the battery cell 11 will rise significantly. Since the battery pack 1 mainly consists of multiple battery cells 11, heat buildup will occur in any of the battery cells 11 unless they immediately dissipate heat when their temperature rises. Furthermore, because the battery pack 1 is installed and fixed inside a relatively sealed temperature-controlled battery chamber 6, it is easy to rapidly raise the temperature of the temperature-controlled battery chamber 6.

[0051] To avoid the impact on the usability of each battery cell 11 due to temperature rise in the battery pack 1 or the temperature-controlled battery chamber 6, the applicant proposes further improvements. Specifically, as shown in Figures 1, 2, and 6, a liquid cooling plate 3 is installed inside the battery box 5, that is, a liquid cooling plate 3 that is thermally connected to the battery pack 1 is installed inside the temperature-controlled battery chamber 6.

[0052] When a heat exchange medium (such as water) is introduced into the liquid cooling plate 3, a temperature difference is created between the heat exchange medium and the temperature-controlled battery chamber 6. In particular, if the battery cells 11 experience thermal runaway, that is, if the temperature of the battery pack 1 is higher than the temperature of the battery cells 11, the heat from the battery pack 1 is transferred to the heat exchange medium in the liquid cooling plate 3 and released from the battery pack along with the flow of the heat exchange medium. As a result, the liquid cooling plate 3 and the battery pack 1 exchange heat, effectively providing immediate, real-time heat dissipation to the battery pack 1 and effectively avoiding the risk of thermal runaway and heat diffusion within the battery pack 1.

[0053] The liquid cooling plate 3 may be installed on the top of the battery pack 1 or on the periphery of the battery cells 11. Here, the liquid cooling plate 3 installed on the top of the battery pack 1 is defined as the first liquid cooling plate 3, and the liquid cooling plate installed on the periphery of the battery cells 11 of the battery pack 1 is defined as the second liquid cooling plate 32. This does not limit the differences in their structures, but is simply to make it easier to distinguish the positions of the liquid cooling plates 3 described later.

[0054] The number of liquid cooling plates 3 may be one. To ensure that each battery cell 11 can exchange heat with the liquid cooling plate 3 and to achieve the objective of dissipating heat and cooling each battery cell 11, as shown in Figure 6, the first liquid cooling plate 31 is installed on top of the battery pack 1, distributed parallel to the heat-insulating member 2, and covers at least each battery cell 11. As a result, the amount of heat released from each battery cell 11 is conducted from the top of the battery cell 11 to the first liquid cooling plate 31. In addition to covering the battery pack 1, the first liquid cooling plate 31 may also further cover the temperature-controlled battery chamber 6. In this way, the amount of heat inside the temperature-controlled battery chamber 6 can be transferred to the first liquid cooling plate 31.

[0055] Preferably, there may be multiple second liquid cooling plates 32. Specifically, as shown in Figures 1 and 2, multiple second liquid cooling plates 32 are all distributed perpendicularly to the heat-insulating member 2 and installed between two adjacent rows of battery cells 11. That is, by having the large surface area of ​​the second liquid cooling plate 32 in contact with the periphery of the battery cells 11, the heat exchange surface between the second liquid cooling plate 32 and the battery cells 11 is increased, effectively ensuring that the amount of heat released from the battery cells 11 can be rapidly conducted to the second liquid cooling plate 32, thereby improving the heat dissipation performance of the battery pack.

[0056] Specifically, as shown in Figures 1 and 2, since multiple second liquid cooling plates 32 are connected in parallel by liquid cooling tubes, when heat exchange medium is supplied to each second liquid cooling plate 32 simultaneously, both rows of battery cells 11 on opposite sides of the second liquid cooling plate 32 can conduct heat to the second liquid cooling plate 32, achieving the objective of simultaneously and evenly dissipating heat from both rows of battery cells 11. In other words, it is possible to maintain the use of each row of battery cells 11 at an optimal ambient temperature. Furthermore, by assembling and fixing the second liquid cooling plate 32 between the two rows of battery cells 11, the overall volume of the battery pack can be effectively reduced. In addition, since the heat exchange medium supplied from the outside is divided by multiple second liquid cooling plates 32, it exhibits the unexpected effect of reducing the flow resistance of the battery's liquid cooling system.

[0057] Furthermore, as shown in Figures 1 and 2, since the battery cells 11 are preferably cylindrical, the side walls of the battery cells 11 are curved. To make the assembly of multiple battery cells 11 more compact, multiple rows of battery cells 11 are arranged alternately. In addition, each second liquid cooling plate 32 is installed in a corrugated shape, and the circumferential surface of each battery cell 11 is bonded to the second liquid cooling plate 32. That is, each second liquid cooling plate 32 has multiple valleys in its curved surface. Each battery cell 11 is bonded in contact with the corresponding valley. Furthermore, by matching the shape and dimensions of each valley with the shape and dimensions of the battery cell 11, the heat exchange area between the battery cell 11 and the second liquid cooling plate 32 is increased, achieving the objective of maximizing the heat exchange efficiency of the battery cells 11 of the battery pack 1 and exhibiting an optimal heat dissipation effect.

[0058] Example 2 The first embodiment described above discloses a heat-insulating battery pack with excellent heat retention performance. Furthermore, since this heat-insulating battery pack can also achieve excellent heat dissipation in conjunction with the liquid cooling plate 3, it solves the problem of the contradiction between heat retention and heat dissipation in conventional battery packs and maintains a relatively balanced relationship between heat retention and heat dissipation. This ensures that the heat-insulating battery pack is in an optimal operating state and improves the stability and reliability of the heat-insulating battery pack and the electrical device using this battery pack.

[0059] Based on the heat-retaining battery pack disclosed in the first embodiment, the present invention further discloses a thermal management method which evaluates the measured temperature value of a monitored battery by comparing it with a preset temperature and adjusts the battery's usage state and heat exchange state. The preset temperature includes a first temperature interval, a second temperature interval, a third temperature interval, a fourth temperature interval, and a fifth temperature interval, ranging from low temperature values ​​to high temperature values. In the first state, if the measured temperature is within the first temperature range, the battery is set to a non-charging and non-discharging state, and the battery's heat exchange state is set to a heating state. In the second state, if the measured temperature is within the second temperature range, the battery's usage state is set to the charging state, and the battery's heat exchange state is set to the heating state. In the third state, if the measured temperature is within the third temperature range, the battery's operating state is set to either a charging state or a discharging state, and the battery's heat exchange state is set to a heating state. In the fourth state, if the measured temperature is within the fourth temperature range, the battery's operating state is set to either a charging or discharging state, and the battery's heat exchange state is set to a non-heating and non-cooling state. In the fifth state, if the measured temperature is within the fifth temperature range, the battery's operating state is set to either a charging or discharging state, and the battery's heat exchange state is set to a cooling state.

[0060] The measured temperature value of the monitored battery here may be the temperature of the monitored battery cell 11, the temperature of the monitored battery pack 1, or the temperature of the monitored battery box 5, but of course, it may be any combination of both or all three.

[0061] In this embodiment, if the first temperature range is within the lowest temperature range, considering that the performance of the power battery deteriorates rapidly when the temperature is below -20°C, it is preferable that the first temperature range be below -20°C. Within this temperature range, in order to achieve the objective of optimally protecting the battery, the battery cells 11 are in a state where charging and discharging are stopped, and the heat exchange medium after heating is controlled to be sent to the liquid cooling plate 3 in accordance with the thermal management of the battery management system. This allows the amount of heat from the heat exchange medium to be effectively transferred to each battery cell 11, achieving the objective of preheating and thawing the battery cells 11. Furthermore, the heat retention member 2 effectively avoids the problem of heat being conducted to the battery box 5 and resulting in loss, and also allows for rapid adjustment to return the battery pack to the optimal temperature range.

[0062] Through long-term research and development and experimentation in the battery field, it has been found that power batteries achieve optimal power input / output, maximum available energy, and longest cycle life when operating within the 15°C to 35°C (or 15°C to 37°C) range. Therefore, appropriate charging of the battery may be initiated when the battery temperature returns from below -20°C to above -20°C.

[0063] According to the plot of the relationship between battery performance and temperature, after the battery is preheated and thawed to -20°C, the battery performance gradually improves as the temperature rises. Preferably, 5°C is taken as the midpoint of the temperature range of -20°C to 15°C, and the temperature range of -20°C to 15°C is divided into a second temperature range of -20°C to 5°C and a third temperature range of 5°C to 15°C, and the battery is charged within the second temperature range.

[0064] When the temperature enters the third temperature range, the user can appropriately select the battery usage state according to the battery pack's usage environment. In order to ensure that the battery is within the optimal temperature range, achieves optimal battery performance, and maximizes the battery's lifespan, the thermal management of the battery management system continuously controls the heating of the heat exchange medium to send it to the liquid cooling plate 3 within the second and third temperature ranges, thereby continuously supplying heat to the battery pack 1.

[0065] The temperature range is -20°C to 15°C, but it is not limited to 5°C; it can also be 0°C, and the temperature range of -20°C to 15°C can be divided relatively evenly into two temperature ranges.

[0066] Preferably, the fourth temperature range may be set to 15°C to 37°C, that is, the first temperature range is within the optimal temperature range. In this case, the battery does not need to actively continue supplying heat; that is, by stopping the heating of the battery cell 11 and utilizing only the heat generated in the battery cell 11 during use and the heat stored in the heat exchange medium inside the liquid cooling plate 3, the battery can be kept in a relatively stable temperature range, that is, the battery can be kept at optimal performance.

[0067] Furthermore, when the battery temperature exceeds 37°C, that is, when the fifth temperature range exceeds 37°C, the fifth temperature range is within a high temperature range. In this case, the battery performance is affected by the high temperature in stages, that is, after the battery enters the fifth temperature range, the battery performance gradually decreases as the temperature rises. For this reason, after the battery enters the fifth temperature range, it is necessary to cool it down during use, and in accordance with the thermal management of the battery management system, the system controls the delivery of a low-temperature heat exchange medium to the liquid cooling plate 3. As a result, the heat from each battery cell 11 is transferred to the heat exchange medium, and finally, as the heat exchange medium is discharged from the battery pack, the liquid cooling plate 3 exhibits an efficient heat dissipation effect on the battery.

[0068] Furthermore, the heat-insulating member 2 effectively prevents heat from the outside of the battery box 5 from being easily or not being conducted at all to the battery pack 1 inside the battery box 5. This allows the battery pack 1 to be quickly returned to the optimal temperature range, and ensures that the battery pack maintains optimal battery performance for a long period of time.

[0069] Furthermore, a first termination temperature value is set within the second temperature interval. If the measured temperature value is higher than the first termination temperature value, the first state is terminated. Preferably, the measured temperature value is set to -15°C or -10°C. Because the battery performance drops sharply to -10°C, when the measured temperature value returns to above -10°C, the battery performance almost recovers, and the first state is terminated.

[0070] Furthermore, a second termination temperature value is set within the third temperature interval. If the measured temperature value is higher than the second termination temperature value, the second state is terminated. Preferably, the measured temperature value is set to 10°C. A third termination temperature value is set within the fourth temperature interval. If the measured temperature value is higher than the third termination temperature value, the third state is terminated. Preferably, the measured temperature value is set to 20°C.

[0071] In other words, the thermal management of the battery management system ensures that the battery temperature remains within the fourth temperature range of 15°C to 37°C by continuously controlling the supply of the heated heat exchange medium to the liquid cooling plate 3 until the measured temperature reaches 20°C, thereby maintaining a dynamic balance within the fourth temperature range. This avoids the problem of the battery temperature dropping below 15°C and the battery performance being outside the optimal range by stopping the heat supply after the battery temperature reaches 15°C, and effectively improves the stability of the battery pack.

[0072] Furthermore, a fourth termination temperature value is set within the fourth temperature interval. If the measured temperature value is lower than the fourth termination temperature value, the fifth state is terminated. Preferably, the fourth termination temperature value is higher than the third termination temperature value, and the measured temperature value is set to 33°C. That is, the thermal management of the battery management system continues to control the delivery of the cooled heat exchange medium to the liquid cooling plate 3 until the measured temperature value reaches 33°C, ensuring that the battery temperature is within the fourth temperature interval of 15°C to 37°C and that the battery is kept in a dynamic balance within the fourth temperature interval. This avoids the problem of the battery temperature rising above 37°C and the battery performance being outside the optimal range by stopping cooling after the battery temperature reaches 37°C, and more effectively improves the stability of the battery pack.

[0073] In summary, the temperatures mentioned above are divided into multiple temperature intervals based on the optimal temperature value for battery performance and the low-temperature mutation value for battery performance. This makes the controllable range of temperature for battery thermal management more rational, and the first, second, third, and fourth termination temperature values ​​effectively avoid the problem of frequently switching the thermal management of the battery management system on and off.

[0074] Most importantly, by using the thermal management method in combination with the heat-insulating material 2 and the liquid-cooling plate 3, the heat retention and heat dissipation performance of the battery pack can be improved very effectively. Furthermore, it is possible to maintain the battery pack and electrical equipment (e.g., electric vehicles) in a state of optimal performance by balancing heat supply and heat dissipation, thereby significantly improving the stability and reliability of the battery pack and electrical equipment. [Explanation of Symbols]

[0075] 1 battery pack 11 battery cells 2. Insulation material 21 Heat insulation layer 22 Air layer 23 Positioning port 24 Insulation Rings 3. Liquid cooling plate 31. First liquid cooling plate 32. Second liquid cooling plate 4 pallets 41 Pressure release port 5 Battery box 51 Outer frame 511 First Section 512 Section 2 513 Third Section 52 Bottom protection plate 531 First pressure release chamber 532 Second pressure release chamber 6 Temperature-controlled battery room

Claims

1. It is a heat-retaining battery pack, A battery pack (1) including multiple rows of battery cells (11), The device includes two heat-insulating layers (21), multiple rows of the battery cells (11) each placed on one of the heat-insulating layers (21), the outer surface of one of the heat-insulating layers (21) on which the multiple rows of the battery cells (11) are placed and the outer surface of the multiple rows of the battery cells (11) are bonded together, the two heat-insulating layers (21) are placed facing each other, a hollow chamber is placed between the two heat-insulating layers (21), the hollow chamber is filled with gas to form an air layer (22), and a heat-insulating member (2) is provided to suppress heat conduction on both opposing sides of the air layer (22). The heat-insulating member (2) is further provided with a plurality of positioning openings (23), The shape and dimensions of each positioning opening (23) are consistent with the shape and dimensions of each battery cell (11). Each of the aforementioned battery cells (11) is mounted and fixed inside the positioning opening (23). A heat-insulating ring (24) is installed on the inner wall of each of the positioning openings (23). The heat-retaining battery pack is characterized in that the heat-retaining ring (24) abuts against the end face of the corresponding battery cell (11).

2. It further includes at least one liquid cooling plate (3), The heat-retaining battery pack according to claim 1, characterized in that at least one of the liquid cooling plates (3) is thermally connected to the battery pack (1).

3. The multiple liquid cooling plates (3) are all distributed perpendicularly to the heat-insulating member (2), Each of the liquid cooling plates (3) is installed between two adjacent rows of the battery cells (11), The heat-retaining battery pack according to claim 2, characterized in that the plurality of liquid-cooling plates (3) are connected in parallel by liquid-cooling tubes.

4. The aforementioned battery cell (11) is a cylindrical cell, The battery cells (11) in multiple rows are arranged and distributed alternately. The heat-retaining battery pack according to claim 3, characterized in that each of the liquid cooling plates (3) is installed in a corrugated shape so that the peripheral surfaces of each of the battery cells (11) are bonded to the liquid cooling plates (3).

5. Further including palette (4), The heat-insulating battery pack according to claim 2, characterized in that the heat-insulating member (2) is installed on the pallet (4).

6. Further including a battery box (5), The heat-insulating battery pack according to claim 5, characterized in that the battery pack (1), the heat-insulating member (2), the pallet (4), and each of the liquid cooling plates (3) are all mounted and fixed inside the battery box (5).

7. The pallet (4) is equipped with multiple pressure release ports (41), Each of the aforementioned battery cells (11) is installed corresponding to each of the aforementioned pressure release ports (41), A pressure release passage is provided between the pallet (4) and the battery box (5). The heat-insulating battery pack according to claim 6, characterized in that the inner bore of the heat-insulating ring (24), the pressure release port (41), and the pressure release passage are sequentially connected to guide the discharge of the hot gas flow generated in the battery cell (11) during a thermal runaway state to the outside of the battery box (5).

8. The battery box (5) includes a bottom protective plate (52) and a curved outer frame (51), The inner wall of the outer frame (51) is provided with a first stage (511), a second stage (512), and a third stage (513). The first stage (511), the second stage (512), and the third stage (513) are installed sequentially along the height direction of the outer frame (51) from one large surface of the outer frame (51). The bottom protective plate (52) is fixed to the first step (511), The heat-retaining battery pack according to claim 7, characterized in that the pallet (4) is fixed to the third tier (513).

9. The pressure release passage includes a first pressure release chamber (531) and a second pressure release chamber (532), Between the pallet (4), the bottom protective plate (42), and the inner wall of the second step (512), the first pressure release chamber (531) is formed. The second pressure release chamber (532) is installed inside the outer frame (51), The heat-retaining battery pack according to claim 8, characterized in that the first pressure release chamber (531) is electrically connected to the second pressure release chamber (532).

10. The heat-insulating member (2) and the inner wall of the outer frame (51) form a temperature-regulating battery chamber (6). The heat-retaining battery pack according to claim 8, characterized in that the battery pack (1) is located inside the temperature-regulating battery chamber (6).

11. A thermal management method used in the thermal battery pack described in Claim 1, This includes evaluating the measured temperature of the monitored battery by comparing it with a preset temperature, and adjusting the battery's operating state and heat exchange state. The pre-set temperatures include a first temperature interval, a second temperature interval, a third temperature interval, a fourth temperature interval, and a fifth temperature interval, ranging from low to high temperatures. In the first state, when the measured temperature value is within the first temperature range, the battery's operating state is set to a non-charging and non-discharging state, and the battery's heat exchange state is set to a heating state. In the second state, if the measured temperature value is within the second temperature range, the battery's operating state is set to a charging state, and the battery's heat exchange state is set to a heating state. In the third state, if the measured temperature value is within the third temperature range, the battery's operating state is set to a charging state or a discharging state, and the battery's heat exchange state is set to a heating state. In the fourth state, if the measured temperature value is within the fourth temperature range, the battery's operating state is set to a charging state or a discharging state, and the battery's heat exchange state is set to a non-heating and non-cooling state. In the fifth state, if the measured temperature value is within the fifth temperature range, the battery's operating state is set to either a charging state or a discharging state, and the battery's heat exchange state is set to a cooling state. A thermal management method characterized by the following.

12. The first temperature interval is below -20°C. The aforementioned second temperature range is -20°C to 5°C. The third temperature range is 5°C to 15°C. The fourth temperature range is 15°C to 37°C. The thermal management method according to claim 11, characterized in that the fifth temperature interval is greater than 37°C.

13. A first termination temperature value is further set within the second temperature interval, The thermal management method according to claim 11 or 12, characterized in that the first state is terminated when the measured temperature value is higher than the first termination temperature value.

14. A second termination temperature value is further set within the third temperature interval, The thermal management method according to claim 11 or 12, characterized in that the second state is terminated when the measured temperature value is higher than the second termination temperature value.

15. A third termination temperature value is further set within the fourth temperature interval, The thermal management method according to claim 11 or 12, characterized in that the third state is terminated when the measured temperature value is higher than the third termination temperature value.

16. Within the aforementioned fourth temperature interval, a fourth termination temperature value is further set. The thermal management method according to claim 15, characterized in that the fifth state is terminated when the measured temperature value is lower than the fourth termination temperature value.

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