Battery monomer, battery and electric device

Abstract

The utility model relates to a battery monomer. The battery monomer comprises a shell and a battery core assembly accommodated in the shell, the battery cell assembly comprises a first pole piece, a second pole piece and a diaphragm; the first pole piece, the second pole piece and the diaphragm are laminated and are formed by winding towards one side of the second pole piece; a heat insulation coating is attached to a heat insulation area, close to the tail end, of the first pole piece, and the heat insulation coating is wound along with the first foil and wraps the periphery of the battery cell assembly. Therefore, the heat insulation coating can achieve a heat insulation effect on the battery cell assembly, and the efficiency of conducting external heat to the interior of the battery cell assembly can be effectively reduced. Even if the battery monomer is abused in the use process, the initial temperature rise point in the battery cell assembly can be increased, and the temperature rise rate can be reduced. Therefore, the battery monomer can delay the temperature point of thermal runaway, and the thermal stability of the battery monomer is remarkably improved. In addition, the utility model also provides a battery and an electric device.

Description

TECHNICAL FIELD

[0001] The utility model relates to new energy technology field especially relates to a battery monomer, battery and electric device. BACKGROUND

[0002] Lithium ion battery has been widely used in various fields due to its high energy density, long cycle life and environmental friendliness. With the increasing energy density of lithium ion battery, the charging speed is also getting faster, and the safety problem is becoming more and more prominent. At present, the problem of thermal abuse of battery is inevitable, and the high external temperature will cause the exothermic chemical reaction of the internal material of the battery cell, thereby triggering a series of chain reactions, and ultimately leading to thermal runaway of the battery. SUMMARY

[0003] Therefore, it is necessary to provide a battery monomer, battery and electric device with high thermal stability to solve the above problems.

[0004] A battery monomer comprises a shell and a battery cell assembly accommodated in the shell, the battery cell assembly comprises a first pole piece, a second pole piece and a separator, and the first pole piece, the second pole piece and the separator are laminated and wound into a shape towards one side of the second pole piece; wherein the first pole piece comprises a first foil, the first foil is sequentially formed with an active area close to a leading end and a heat insulation area close to a trailing end along the winding direction, the two sides of the active area are attached with a first active material layer, at least one side of the heat insulation area is attached with a heat insulation coating layer, and the heat insulation coating layer is wound with the first foil and covers the outer periphery of the battery cell assembly.

[0005] In one embodiment, the length of the second pole piece along the winding direction is equal to the length of the active area along the winding direction.

[0006] In one embodiment, the heat insulation coating layer is formed on the opposite sides of the heat insulation area.

[0007] In one embodiment, the heat insulation coating layer is an aerogel layer.

[0008] In one embodiment, the density of the heat insulation coating layer is 0.13 g / cm3, and the average pore size is 25 nm.

[0009] In one embodiment, the heat insulation coating layer is a silica aerogel layer.

[0010] In one embodiment, the battery cell assembly is pressed into a flat shape, and the length of the heat insulation area along the winding direction is equal to four times the width of the battery cell assembly.

[0011] In one of the embodiments, the first electrode tab is a negative electrode tab and the second electrode tab is a positive electrode tab.

[0012] The battery cell, the thermal insulation coating is attached to the thermal insulation area close to the tail end of the first electrode tab, and the thermal insulation coating is wrapped around the outer periphery of the battery cell assembly along with the first foil. Therefore, the thermal insulation coating can play a role in thermal insulation of the battery cell assembly, and can effectively reduce the efficiency of external heat conduction to the inside of the battery cell assembly. Even if the battery cell described above is in the case of thermal abuse during use, the starting temperature point inside the battery cell assembly can be increased and the temperature rising rate can be reduced. It can be seen that the battery cell described above can delay the temperature point of thermal runaway, and the thermal stability is significantly improved.

[0013] A battery comprising a plurality of battery cells as described in any of the preferred embodiments described above.

[0014] An electrical device comprising a battery cell as described in any of the preferred embodiments described above or a battery as described in the embodiments described above. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0016] Figure 1 The structure of the battery cell in one embodiment of the present application is shown in the figure.

[0017] Figure 2 The structure of the battery cell in one embodiment of the present application is shown in the figure. Figure 1 The structure of the battery cell in one embodiment of the present application is shown in the figure.

[0018] Figure 3 The structure of the battery cell in one embodiment of the present application is shown in the figure. Figure 2 The structure of the battery cell in one embodiment of the present application is shown in the figure.

[0019] Figure 4 The figure shows the thermal box test data. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below. In the following description, a lot of specific details are set forth in order to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application, therefore the present application is not limited by the specific embodiments disclosed below.

[0021] In the description of the utility model, it is understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model.

[0022] In addition, the terms "first" and "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the utility model, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0023] In the utility model, unless otherwise specifically defined and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship of two elements, unless otherwise specifically limited. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0024] In the utility model, unless otherwise specifically defined and limited, the first feature "on" or "under" the second feature can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0025] It is to be noted that when an element such as a layer, region or substrate is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element or intervening elements can be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element, there are no intervening elements present. It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements can be present. As used herein the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0026] Referring to Figure 1 The utility model provides a kind of battery monomer 10. In addition, the utility model further provides a kind of battery and electric device, above-mentioned electric device includes above-mentioned battery or above-mentioned battery monomer 10, and can be provided with electric energy by above-mentioned battery or above-mentioned battery monomer 10.

[0027] Above-mentioned electric device can be vehicle, mobile phone, portable equipment, notebook computer, ship, spacecraft, electric toy, electric tool, energy storage device, amusement device, elevator and lifting equipment etc. Electric toy includes fixed or mobile electric toy, for example, game machine, electric car toy, electric ship toy or electric aircraft toy etc.;Electric tool includes metal cutting electric tool, grinding electric tool, assembly electric tool and railway electric tool, for example, electric drill, electric grinder, electric wrench, electric screwdriver, electric hammer, impact drill, concrete vibrator and electric planer etc.;Energy storage device can be energy storage wall, base station energy storage, container energy storage etc.;Amusement device can be carousel, jump machine etc.

[0028] Vehicle can be fuel automobile, gas automobile or new energy automobile, and new energy automobile can be pure electric vehicle, hybrid electric vehicle or extended range vehicle etc.;For new energy automobile, above-mentioned battery can be used as driving power supply, to replace fossil fuel to provide driving power.

[0029] Above-mentioned battery includes multiple battery monomers 10, and multiple battery monomers 10 can be connected by series connection, parallel connection or series connection and parallel connection. Above-mentioned battery can be battery pack or battery module. When above-mentioned battery is battery pack, battery pack specifically includes battery management system (BMS) and multiple above-mentioned battery monomers 10. Multiple battery monomers 10 can be connected by series connection, parallel connection or series connection and parallel connection mixed mode, and are connected with battery management system to form battery pack, and above-mentioned battery management system controls and monitors the working state of each battery monomer 10. In addition, multiple battery monomers 10 can be connected by series connection and / or parallel connection first, and form battery module with module management system, and then multiple battery modules are connected by series connection, parallel connection or series connection and parallel connection mixed mode, and are connected with battery management system to form battery pack.

[0030] The aforementioned battery cell 10 can be a lithium-ion battery, sodium-ion battery, etc., and its shape can be cylindrical, square, or other shapes. Specifically, the battery cell 10 in this embodiment is a lithium-ion square-shell battery. In one embodiment of this utility model, the battery cell 10 includes a cell assembly 100 and a casing 200.

[0031] The housing 200 has a hollow structure, with internal space for accommodating the wound battery cell assembly 100, electrolyte, and other components. At least one end of the housing 200 has an opening through which the wound battery cell assembly 100 can be inserted. In this embodiment, the wound battery cell assembly 100 is wound and flat, and one or more wound battery cell assemblies 100 can be accommodated within a single housing 200. Specifically, in this embodiment, the outer contour of the housing 200 is cuboid, and its opening is rectangular. After the battery cell assembly 100 is inserted into the housing 200, its opening can be sealed by a cover plate 300, thereby creating a relatively closed environment inside the housing 200 to isolate the battery cell assembly 100 from the external environment.

[0032] Please refer to the following: Figure 2 In one embodiment of the present invention, the battery cell assembly 100 includes a first electrode 110, a second electrode 120, and a separator 130.

[0033] The separator 130 is located between adjacent first electrode 110 and second electrode 120, and is used to separate the first electrode 110 and second electrode 120 to avoid short circuits. In the fabrication of the wound cell assembly 100, the first electrode 110, second electrode 120, and separator 130 are first stacked, then wound, pressed, and flattened. For the cell assembly 100 suitable for cylindrical batteries, the winding is completed by finishing the winding process, eliminating the need for pressing.

[0034] The relative positions of the first electrode 110, the second electrode 120, and the separator 130 may differ for different models of wound battery cell assemblies 100. For example, in this embodiment, there is only one first electrode 110, one second electrode 120, and one separator 130. The second electrode 120 is located above the first electrode 110, and the separator 130 is sandwiched between the first electrode 110 and the second electrode 120. Specifically, in this embodiment, the first electrode 110 is the negative electrode, and the second electrode 120 is the positive electrode. Obviously, in other embodiments, the first electrode 110 can also be set as the positive electrode, and the second electrode 120 as the negative electrode.

[0035] Please refer to the following: Figure 3The first tab 110 includes a first foil 111, which is sequentially formed with an active region (not labeled in the figure) near the head end and a thermal insulation region (not labeled in the figure) near the tail end along a winding direction. The head end of the first foil 111 refers to one end inside the battery cell assembly 100, the tail end refers to one end outside the battery cell assembly 100, and the winding direction refers to the extension direction of the first foil 111. Before winding, the head end and the tail end of the first foil 111 refer to the two ends of the length direction thereof.

[0036] Further, the first foil 111 is attached with a first active material layer 112 on both sides of the active region, and is attached with a thermal insulation coating 113 on at least one side of the thermal insulation region. The thermal insulation coating 113 is wound along with the first foil 111 and covers the outer periphery of the battery cell assembly 100.

[0037] For the purpose of the present application, since the first tab 110 is a negative electrode tab, the first foil 111 is usually made of a copper foil, and the first active material layer 112 is a negative electrode active material layer formed of graphite, silicon or the like. The thermal insulation coating 113 is formed of a material with low thermal conductivity, good insulation and high chemical stability, which can play a good thermal insulation role.

[0038] As can be seen, after the battery cell assembly 100 is wound and prepared, the thermal insulation coating 113 can play a thermal insulation role on the battery cell assembly 100, thereby effectively reducing the efficiency of external heat conduction to the inside of the battery cell assembly 100. Even if the above battery monomer 10 has a case of thermal abuse during use, the initial temperature rising point inside the battery cell assembly 100 can be increased and the temperature rising rate can be reduced, thereby delaying the temperature point of thermal runaway and improving the thermal stability.

[0039] In particular, in the present embodiment, the thermal insulation coating 113 is formed on the opposite sides of the thermal insulation region of the first foil 111. On the one hand, the thermal insulation coating 113 is formed on both sides to improve the thermal insulation effect. On the other hand, the thermal insulation coating 113 on both sides can be arranged flush with the first active material layer 112 on both sides, thereby ensuring that the thickness of the first tab 110 is substantially uniform everywhere, and further avoiding uneven stress distribution of the first tab 110 due to inconsistent thickness during winding.

[0040] In addition, in the present embodiment, the length of the thermal insulation region along the winding direction is equal to four times the width of the battery cell assembly 100. The length of the thermal insulation region along the winding direction is the length of the thermal insulation coating 113. For a flat battery cell assembly 100, the length required for the thermal insulation coating 113 to wind one turn is approximately equal to twice the width of the battery cell assembly 100. As can be seen, the thermal insulation coating 113 with a length equal to four times the width of the battery cell assembly 100 can wind two turns around the outer periphery of the battery cell assembly 100, thereby further improving the thermal insulation effect.

[0041] The battery cell 10 of the present application has been tested in a hot box and has shown that its thermal stability has been significantly improved. The specific process of the hot box test is as follows: after the battery cell 10 is fully charged, the temperature box is set to rise to 155℃±2℃ at a rate of 5±2℃ / min, and the temperature is kept for 30min. Under this environment, the battery cell 10 does not catch fire or explode, and the detailed data are shown in Table 1. Figure 4 .

[0042] The inventors have found that adding an additive to the electrolyte to block the chain reaction can also improve the problem of thermal runaway caused by thermal abuse to a certain extent. However, the additive usually brings other side reactions, thereby affecting the cycle, rate, low-temperature charging and discharging and other series of performances of the battery cell assembly 100. Based on the above consideration, the present application solves the problem of thermal runaway caused by thermal abuse by coating the thermal insulation coating 113 on the edge of the first tab 110 close to the tail end. Since no additive is added to the electrolyte, the chemical system is not changed, the structure is simple and easy to realize, and the performance of the battery cell assembly 100 is not weakened.

[0043] In the present embodiment, the thermal insulation coating 113 is provided as an aerogel layer. The aerogel layer has a microporous structure, and the electrolyte can flow smoothly in and out of the battery cell assembly 100 through the microporous structure. When the electrolyte in a specific area of the battery cell assembly 100 evaporates, the electrolyte in other parts can flow to this area through the microporous structure, thereby ensuring that the electrolyte can uniformly wet the battery cell assembly 100, ensuring the normal operation of the battery cell assembly 100 while also inhibiting the spread of thermal runaway.

[0044] Specifically, the density of the thermal insulation coating 113 is 0.13g / cm3, and the average pore size is 25nm. In the present embodiment, the thermal insulation coating 113 is provided as a silica aerogel layer. Silica has a low thermal conductivity, good insulation performance and good heat resistance, and silica is easy to form a film on the first foil 111.

[0045] More specifically, the thermal insulation coating 113 can be formed by the following process: first, tetraethyl orthosilicate is dissolved in solvent methanol, and NaOH aqueous solution is added to adjust the pH to about 6 for hydrolysis and polycondensation reaction and to form sol. The molar ratio of tetraethyl orthosilicate:methanol:deionized water is 1:8:4. Then, the sol is coated on the thermal insulation region of the first foil 111 by gravure coating or the like. Before that, the coating of the first active material layer 112 can also be performed. Of course, the first active material layer 112 can also be coated after the sol is coated. Then, the coated first tab 110 is placed in an oven at about 50℃ for drying, and after aging, the sol forms a gel. Finally, the temperature of the oven is adjusted to about 700℃, and the drying time is set to 90s, so that a silica aerogel layer with a density of 0.13g / cm3 and an average pore size of 25nm is formed.

[0046] Please refer to Figure 2 The second tab 120 includes a second foil 121 and a second active material layer 122 attached to opposite sides of the second foil 121. Compared with the first tab 110, the surface of the second foil 121 is an active area, and no thermal insulation area is arranged. For the purpose of the present application, since the second tab 110 is a positive electrode tab, the second foil 121 is usually an aluminum foil, and the second active material layer 122 is a positive electrode active material layer formed by lithium manganate, lithium cobaltate, lithium iron phosphate, etc.

[0047] Further, in the present embodiment, the length of the second tab 120 along the winding direction is equal to the length of the active area along the winding direction. It can be seen that the total length of the second tab 120 is less than the total length of the first tab 110, thereby helping to reduce the thickness of the battery cell assembly 100. Moreover, since the thermal insulation area of the first tab 110 does not have active material, it cannot exchange particles with the second tab 120 to generate electrical energy, so shortening the total length of the second tab 120 will not cause the energy density of the battery cell assembly 100 to be lost.

[0048] The above-mentioned battery cell 10, the thermal insulation coating 113 is attached to the thermal insulation area close to the tail end of the first tab 110, and the thermal insulation coating 113 is wound with the first foil 111 and wrapped around the outer periphery of the battery cell assembly 100. Therefore, the thermal insulation coating 113 can play a thermal insulation role for the battery cell assembly 100, and can effectively reduce the efficiency of external heat conduction to the inside of the battery cell assembly 100. Even if the above-mentioned battery cell 10 has a case of thermal abuse during use, the initial temperature rise point inside the battery cell assembly 100 can be increased and the temperature rise rate can be reduced. It can be seen that the above-mentioned battery cell 10 can delay the temperature point of thermal runaway, and the thermal stability is significantly improved.

[0049] The technical features of the above-mentioned embodiments can be combined in any way. In order to make the description simple, not all possible combinations of the technical features in the above-mentioned embodiments are described, but as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present application.

[0050] The above-mentioned embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which belong to the protection scope of the present application. Therefore, the protection scope of the present application patent should be subject to the appended claims.

Claims

1. A battery cell comprising a housing and an electrode assembly housed in the housing, the electrode assembly comprising a first electrode tab, a second electrode tab, and a separator, characterized in that, The first pole piece, the second pole piece and the diaphragm are laminated and wound into shape towards one side of the second pole piece; wherein the first pole piece comprises a first foil, the first foil sequentially forms an active area close to a head end and a heat insulation area close to a tail end along a winding direction, first active material layers are attached to both sides of the active area, a heat insulation coating is attached to at least one side of the heat insulation area, and the heat insulation coating is wound along with the first foil and covers the outer periphery of the battery cell assembly.

2. The battery cell of claim 1, wherein, The length of the second pole piece along the winding direction is equal to the length of the active area along the winding direction.

3. The battery cell of claim 1, wherein, The opposite sides of the heat insulation area are both formed with the heat insulation coating.

4. The battery cell of claim 1, wherein, The heat insulation coating is provided as an aerogel layer.

5. The battery cell of claim 4, wherein, The density of the heat insulation coating is 0.13 g / cm3, and the average pore size is 25 nm.

6. The battery cell of claim 4, wherein, The heat insulation coating is provided as a silica aerogel layer.

7. The battery cell of claim 1, wherein, The battery cell assembly is pressed into a flat shape, and the length of the heat insulation area along the winding direction is equal to four times the width of the battery cell assembly.

8. The battery cell of any one of claims 1 to 7, wherein, The first pole piece is a negative pole piece, and the second pole piece is a positive pole piece.

9. A battery, characterized by A plurality of battery cells as claimed in any one of claims 1 to 8.

10. An electrical device, characterized by A battery as claimed in claim 9.

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